VTX 1300 Carburetor Adjustment

[Scar]

You may have just purchased a new exhaust and/or air intake and are wondering how you should "tune" the carburetor. First off if you just "fire the bike up" with the new parts installed, THE BIKE WILL RUN. Depending on how "free flowing" the aftermarket parts are that you installed the bike will run anywhere from "pretty good" to "pretty lean and very nervous", but it will run. So now the bike has to be TUNED. The easiest, least expensive, quickest, most predictable and fool proof method of rapidly tuning it would be to ADJUST the stock parts that are already in the carb. Some people venturing into the "mods" game want to do them all at the same time... this has OFTEN been proven to cause problems for the neuvo MC "wrench". DO NOT remove the PAIR system during the same session that you are tuning the carb. :nono: , it is common while working with the PAIR removal to "miss" something in the process and have an open vacuum line or "other" air leak. Many who have done both of these mods simultaneously have ended up fiddling with their carb for days/weeks on end chasing their tails looking for what went wrong with the carb tuning while all the time it was an error in the PAIR system removal. There have been some war stories spread about how difficult it is to tune a carburetor.. bull hocky! The most difficult part of tuning a carb on a VTX 1300 is removing the fuel tank for the first time and figuring out how to disconnect the electrical connectors under the tank.

So, what comes first eh? REMOVE THE FUEL TANK. Follow the directions in the service manual.. everyone should have a service manual.. the money you save in THIS carb tuning process alone will pay for a service manual. The money you save doing your first valve adjust using the service manual would buy a nice set of tools that can be used in OTHER money savings projects... EVERYONE needs a service manual..

Next REMOVE the air filter and backing plate. I won't "get into" hooking and unhooking the hoses attached behind the backing plate, they are pretty straight forward and will become part of your "learning process" of the easiest ways to rapidly navigate through assembly/disassembly.

NOW the carburetor is EXPOSED. Sitting on top of the carb you will see the vacuum chamber cover. Remove the cover and then remove the compression spring under the cover. Now gently grab the diaphragm/piston rubber and pull it out.. the Vacuum piston (slider piston is what most old timers call it) is attached to the diaphram and the whole package will come out with it. YOU ARE ALMOST DONE AND READY TO PUT THINGS BACK TOGETHER.. see, I told you.. removing the tank was the most difficult part of the process... unscrewing the 4 vacuum chamber cover screws was no big deal, right?
Look at the slider piston and you will see a tappered "needle" sticking out the bottom of it, that is the jet needle. Look inside the slider piston and you will see the Jet needle holder. The jet needle holder is next to be removed.. you will see in the center of the holder it will accept a Phillips head screwdriver which can be used to "unscrew" the cam locks, BUT the "best" method is to use a small socket and fit over the head of the "cap" and unscrew the cap... I'm thinking it's an 8mm.. difficult to recall those things sometimes at my age, but you'll discover the correct size. Twist the cap counter clockwise just as tho you were unscrewing any "standard" nut or bolt and you will feel a "pop" after making a very small motion.. that was the cams unlocking.. the cap can now be removed, it is "unlocked".

Under the needle holder cap there is a small spring "screwed" onto a plastic "tit" protruding from the bottom of the cap... well actually the "tit" has no threads, so the spring is not "screwed" on, but consider it so... instead of "pulling" the spring off and distorting it's shape, give a "light force" pull on the spring while unscrewing it from the "tit" and set the spring aside. The "tit" does not protrude very far, but it must be "trimmed" for "heavy breather" mods, so go ahead and trim it now even if you are doing a "light breather" tune... Take some TOENAIL clippers (those are the large ones, not to be confused with fingernail clippers) and "snip" the "tit" in half.. that should be enough for heightened needle raising and still provides enough remaining "tit" for the small spring to be screwed back onto... set the needle holder cap aside.

Remove the needle from the slider piston.. place your shims into the needle "point" and make sure they slide all the way to the needle head with the washer/shim hole big enough so free movement along the needle is achieved. Hold the slider piston in your left hand and turn it at an upwards angle and insert the needle INTO the slider piston hole, passing through the CENTER hole in the slider piston (this process will not work for "left handers", you will have to purchase a Yamaha carburetor). Face the slider piston DOWN and the needle should be hanging from the bottom of the slider piston and sitting "on" the shims/washers INSIDE the piston.

Take the SMALL spring that was unscrewed from the underside of the needle holder cap and screw it back onto the shortened "tit" under the needle holder. Put the needle holder cap into the slider piston with the small needle spring tensioner sitting on top of the needle head. (If the 8mm socket is placed onto the top of the needle holder cap "nut" the tension is enough to hold the cap.. the needle cap holder can be easily inserted into the slider piston with this method utilizing a socket extender). Twist the needle holder cap clockwise (even the left handers) as tho "tightening" and you will feel the cams lock into place... that's it, the needle holder is locked. If enough of the "tit" was trimmed, this should be a relatively easy "twist"... Hold the slider piston with one hand and "wiggle" the needle with the fingers on the other hand... the needle should "wiggle" (movement), this assures true alignment into the emulsion tube :) . If the needle is "stiff" and won't "wiggle", then the "tit" was not trimmed enough :nono: ... go back and trim more from the tit until free needle movement is achieved. (If you are using a DJ needle, the tit must also be trimmed for the same reasons)

Replace the diaphragm spring onto the needle holder cap and replace the vacuum chamber cover.. NOTE: There is an irregular "shape" in the cap that must be matched to it's mating surface when remounting, this is what the manual calls the "tab and air passages"... "Snug" the vacuum cap screws and continue reassembly.

Under the carb is the A/F screw (see manual), the stock screw head requires a "D" type tool for adjustment. If you slightly dent the end of an empty .22 shell casing, this will fit into the hole and can be used to unscrew the "D" screw. Take the "D" screw completely OUT. On the top of the "D" screw head will be a spring followed by a washer and then an "O" ring.. save these parts and reassemble in the same order when putting the A/F screw back in.

While the A/F screw is OUT, use a hacksaw blade or some similar device to cut a thin channel into the head of the top of the "D" screw.. this slot or channel should be wide enough for a flathead screwdriver blade to fit into for A/F adjustment. Once the slot has be cut into the screw/needle head and the screwdriver blade fits, replace the spring/washer and "O" ring and replace the A/F needle into the needle jet hole and screw IN. Take your screw driver and screw in the needle until it LIGHTLY seats or stops turning ;) ... don't get anal about this and over tighten or damage could be caused to the needle/jet mating surfaces :( . If you error on "seating", error on the LOOSE side, final tuning will not be affected by a minute discrepancy of "seating" at this stage of tuning. Turn the A/F screw OUT 2 1/2 turns with the screwdriver.

Reassemble the airbox and fuel tank.

Before firing the engine, look at the CHOKE KNOB and push it in all the way... any flexing of the carb while working on it will flex the choke cable and pull the choke out... it will not run properly with the choke pulled out AT ALL and final tuning cannot be achieved.

Shim heights:
"Open" style airbox and aftermarket "free flow" pipes... usually about 2or 3 shims.
Airbox flowing more air than stock design, but not in the "heavy breathing" class and/or pipes either free flow or somewhat restricted... usually about 1or 2 shims
Stock airbox (K&N filter in stock box is still "stock") and after market pipes... usually 0 or 1 shims
Stock airbox and stock pipes... tune the A/F screw for maximum performance...

A/F settings:
While determining proper main jet circuit settings the A/F screw should be set at 2 1/2 turns and NO adjustments made to it until the high speed circuit has been properly tuned -- Turning the screw IN leans the mixture... turning the screw OUT richens the mixture -- Fine tuning the A/F screw should be done in no more than 1/8 turn increments... very fine tuning will be even less... it is highly recommended to "slot" the "D" screw and tune the A/F screw with a screw driver... a 90 degree drive is useful if you have one... improvise.

SLIDER PISTON SPRING:
That's what I call the big spring directly under the vacuum cap and sitting on the needle holder cap. -- Most tuners that have springs of the type found in the VTX carb shorten the spring for faster throttle response... this is not necessary for the bike to operate, but you will shorten the response time if you shorten it... I would not recommend shortening it past 5 1/16"... that is the lenght of the shorter DJ kit supplied spring and is a proven entity... The Keihin spring is of slightly larger diameter wire so a "safe" fudge factor is built in if you cut it to 5 1/16", most do... you can cut it less than that if you are nervous, but you shouldn't have any problems with 5 1/16"... place the cut end DOWN into the slider piston and resting on the needle cap... uncut end UP against the vacuum cover.. that is the "common" practice (and no bannanas on boats either).

Most any needle design or jet design will work with the Keihin carb as long as they are set to the proper height and have the correct diameter... It has been my findings that the stock Keihin needle and jet work more "smoothly" if properly shimmed than some other designs because of the needle design and large diameter jet size... The Keihin design is just more forgiving and not as "touchy" as some other designs and need I say you are not required to remove the float bowl cover to change main jet sizes?... The Keihin 195 main jet suits most all purposes... if you require more than that you are past the "beginning" tuner stages and in that case you might think about a Keihin 200 or 205 (DJ equivalents of 213 and 218)... I don't think more than a 205(/218) would be required by anyone unless cam, piston, valve and porting changes have been made... in which case I would like to communicate with you on your engine mods and findings... you most likely won't require any "advice", but I would like to hear about extensive engine mods... mine will retain the stock configuration... I have a 1200cc street fighter for speed.

Have fun and if I am "not around" to answer any possible questions (I have a somewhat irregular schedule at times), I would recommend asking Retro Rich.. He has a mechanical mind and a healthy grasp on the tuning philosophy.

Radio Shack Shims:
Radio Shack Part # 64-3022
Package of 100
Steel Flat Washers
20 each: #2, #4, #6, #8, #10

They are in the Hardware section of the store -- In the plastic pull out trays that are divided into sections.. Plastic bag... Looking at the bag I would say we are using the #4 washers.. anyway it is the second from the smallest... we "miched" em several years ago and can't recall, they are like 0.019 or 0.020 or pretty close to that neighborhood.. they work! -- Oh yea, they now cost $1.99/pkg -- inflation.

Any "washer/shim" of similar thickness (0.020") with a hole big enough for the needle to comfortably slide through and small enough for the needle head to sit on will work just fine.

I could write another entire page on "tuning techniques", but it has already been done in what I consider a comprehensive and accurate manner... use it as your tuning Bible -- Factory Pro http://www.factorypro.com/tech/carbtun.html

Don -- AKA "Scars" :cheers:

[BigDog]

Thanks for the detailed write up, very impressive & thanks for taking the time to write this up.

[islandcycle]

i have a 2005 1300r in the shop and i can't figure it out. It idles fine, even revs up fine. when i put it in gear and throttle up it falls on its face. the bike has a hypercharger and v&h longshots. i called kury akyn and jetted to their specs.any help would be appriciated.
scott

[DillDawg]

i have a 2005 1300r in the shop and i can't figure it out. It idles fine, even revs up fine. when i put it in gear and throttle up it falls on its face. the bike has a hypercharger and v&h longshots. i called kury akyn and jetted to their specs.any help would be appriciated.
scott
Forget the Kuryakyn jets...they're all wrong.
You'd be better off with stock carb parts. Just set the A/F at 2-1/2 out, and stick a couple (2-3) shims under the needle. Very easy.
Stock slow - 55
Stock main - 195
Stock needle

If you want to get fancy - you can experiment with larger Keihin jets....but that setup will be a much better starting point.

[islandcycle]

i'll see what happens. i think thats where i am. this thing is making me nuts

[Orville]

i have a 2005 1300r in the shop and i can't figure it out. It idles fine, even revs up fine. when i put it in gear and throttle up it falls on its face. the bike has a hypercharger and v&h longshots. i called kury akyn and jetted to their specs.any help would be appriciated.
scott Howdy
Kuryaken to prevent being sued seems to jet every thing fat. We could not get over 40 MPH and found out that we did not have the seal on the slider installed correctly. then it did all kinds of weird stuff but would ran better. So off to the Honda shop and found out that the choke was stuck in the closed position. I assume that my partner jamed the cable when he took it off or put it on. Got that fixed, leaned the jetting ( we are at 6000 ft above sea level) runs like an ape about to get raped.

[BigPapaVTX]

I had already had the dealer put a dynojet stage 1 in the bike with my pipes. After putting on the Hypercharger I figured it was a simple a/f adjustment. Nope and the dealer swapped out the pilot to a 62, told me to pick it up and it ran great. I hit the throttle and all sorts of hesitation and it fell over on its face at wide open throttle. To avoid more charges I decided to use the garage and thousands of dollars of tools where I store it, at my buddies.

I now understand and have no fear. I actually put back in a 185 at 2 1/2 turns and clip 4 with one shim and it runs excellent. It does feel like it has a slight flat spot. I am going to a stage 3 kit but wanted to have a base to be able to go back to if I ran into trouble.

[Retro Rich]

If you have the stock main and pilot, I'd put those back in. Smoother fuel delivery, easier to tune. But, this writeup is pretty famous out there and very good. Has helped a lot of people (including me when I started tearing into mine).

[BigPapaVTX]

If you have the stock main and pilot, I'd put those back in. Smoother fuel delivery, easier to tune. But, this writeup is pretty famous out there and very good. Has helped a lot of people (including me when I started tearing into mine).Thanks, going to go read it in entirety. I am actually thinking of going to a stage 3 (220 jet) as the pipes are wide open and a buddy said his runs very well. Any thoughts on that?

[Retro Rich]

DJ or Keihin style main jet? The Keihin style 195 equates out to a DJ 208. So, technically, a DJ 210 isn't much bigger. What air intake system are you running?

[BigPapaVTX]

DJ or Keihin style main jet? The Keihin style 195 equates out to a DJ 208. So, technically, a DJ 210 isn't much bigger. What air intake system are you running?Actually it is a factorypro.com jet kit.

I currently have the Cobra lowboy exhaust with big city thunder baffles and the hypercharger pro.

[Retro Rich]

Hhhhmmmm; try a Factory Pro/Keihin Style 200 (I think they have that size) with no shims and see what it does. If it's still having some flat spots, go up one size or shim the main on the next size up from what you've got with 1 shim, progressively work your way up to 3 shims. If you have to go to 3 shims and still having flat spots, go up to the next size main jet with no shims, etc., etc. Shimming on your main jet delivers more fuel, more quickly on the main circuit if you follow me (I'm sure you do).

[BigPapaVTX]

Hhhhmmmm; try a Factory Pro/Keihin Style 200 (I think they have that size) with no shims and see what it does. If it's still having some flat spots, go up one size or shim the main on the next size up from what you've got with 1 shim, progressively work your way up to 3 shims. If you have to go to 3 shims and still having flat spots, go up to the next size main jet with no shims, etc., etc. Shimming on your main jet delivers more fuel, more quickly on the main circuit if you follow me (I'm sure you do).Ok, here is the question. I ordered a Dynojet stage 1 kit and the dealer put it in. When I pulled the jet it says 195. Now, is there a way to tell if they truly did anything as i hear that the vtx comes with a 195 anyway,

[Retro Rich]

The DJ 195 and Keihin 195, although they share the same "number" are not the same size. The DJ 195 is smaller than the Keihin 195 (a Keihin 195 actually interpolates out to a DJ 208); so, the way to tell if they did anything is if you're running the DJ needle (needle with a clip). If you are, they did put in the stage 1 kit with a DJ 195 (the DJ needle and Keihin jet styles don't work well together at all, due to different design; and if I remember correctly, the DJ jets do have a "DJ" stamped on them somewhere near the numbering/size). Thus, you're running a smaller main jet than what the carb came with from the factory.

Make sense?

[BigPapaVTX]

Yep, makes total sense. The needle does have the clips on it so I am now positive they just put the DJ 195 in. I am getting the Factory Pro kit which is supposed to be good. I will post up what I find when I am done. Thanks for all the insight!!

[Scar]

barttoday put some pics with the post... cool :)

http://www.vtxcafe.com/showthread.php?t=3079

[barttoday]

Hope you didn't mind Scar.... Your write-up helped me out a lot. I thought I could just contribute a little, and with Big-x's help get the pics posted to go along with it.

[RockyVTX]

This is a great article. Thanks for posting. Would like to ask a more specific question though. I live at 9500 and work at 6500 feet. I purchased an air box cover with a nice "V" cutout to provide more air. Since I ride at such high altitudes, would I be able to compensate with just an A/F admustment?

[Scar]

This is a great article. Thanks for posting. Would like to ask a more specific question though. I live at 9500 and work at 6500 feet. I purchased an air box cover with a nice "V" cutout to provide more air. Since I ride at such high altitudes, would I be able to compensate with just an A/F admustment?

If you have stock pipes, then you will probably only have a minor A/F adjustment to make for "perfect" tune... at those elevations, depending on how it is set now you may require nothing... look at the plugs.. tune by response.

If you do have to make an A/F adjustment.. you might want to cut the spring down while you are working on the carb.. will give you faster response time.. not necessary to make the bike run tho. :cheers:

[RockyVTX]

Thanks again, Scar. I was hopin it might be that simple. Just seems to lag a little when goosed but quickly catches up.

After reading the article I was particularly interested in cutting down that spring to improve response.

What would you think of using a tach to monitor the final adjustment of the A/F while idling? I was thinking that maybe finding the spot where the rpms are highest while gently tweaking?

[Scar]

Thanks again, Scar. I was hopin it might be that simple. Just seems to lag a little when goosed but quickly catches up.

After reading the article I was particularly interested in cutting down that spring to improve response.

What would you think of using a tach to monitor the final adjustment of the A/F while idling? I was thinking that maybe finding the spot where the rpms are highest while gently tweaking?

Yea, that's pretty "old school" for getting them running... but for "riding" I've found that tuning for response is more satisfying.. that's what the "big boys" do also (racers)... you don't really need to utilize the method that you mentioned and it would be a real crap shoot if it came out "right" performance wise.

[Ian]

Hey Scar.
I've attached a hyper charger and it works great when your on the throttle.
I would like to change the main jet as it bogs out at the low end. It idles fine, it just dies out a bit when i give it a little gas. Do I have to take the carb off to change the main jet? Do you have a quick way of doing so? I will be riding in the mountains in a couple weeks and may have to change the jet again.
Thanks in advance for any help.
Ian

[CUZMOTEEFOOSWA]

Take the four screws out of the bottom of the carb that holds the float bowl.Once this is removed you will see the head of the main jet with the slots cut into it for a flathead screwdriver.Remove the jet and replace with new.

[Scar]

Hey Scar.
I've attached a hyper charger and it works great when your on the throttle.
I would like to change the main jet as it bogs out at the low end. It idles fine, it just dies out a bit when i give it a little gas. Do I have to take the carb off to change the main jet? Do you have a quick way of doing so? I will be riding in the mountains in a couple weeks and may have to change the jet again.
Thanks in advance for any help.
Ian

Ian: Whatever you do, you do NOT have to remove the carb... If you are only running the hyper and stock pipes then a simple A/F adjustment should suffice (or possibly ONE shim under the needle head, no more).. If you are running "free flowing" pipes then you will have to shim under the stock needle with the stock mainjet two or three shims depending on your pipes... that would be approx. 0.040" to 0.060" under the needle head... read the beginning of this thread carefully and you should have no problems.

If the bike is "tuned" for the elevation that you live, then riding to a higher elevation will make it run a little richer... no problem, it will still run... if you do this a LOT then you could run 89 or higher octane at your "home" elevation and switch to 87 Octane fuel when you "head for the hills"... this will lean it out a little.. don't worry about it tho.. a little on the "fat" side is ok...

Have fun on the ride.

Don

[Ammodude83]

Scar, Retro,
I have a 2006 VTX 1300R and have serious carb problems now. I performed Clayton Mod putting 5 holes in each pipe- bike ran fine. Installed K&N air filter-bike ran fine. Purchased and installed Brown county X-Flame air box cover and bike ran rough...would run better with choke pulled quarter way out. Talked with Honda dealer and he recommended Cobra stage 1 rejet kit to be installed, so I had that performed and the bike was stuggish on initial throtting and run like a bat out of hell once RPM were higher. But, by the time I got my bike half way home from the honda shop which is about 10 miles away the bike didn't even want to run. It kept choking out all through mid-range and the only way to keep it running was to have the throttle quarter way open. Mechanic called Cobra and they recommended putting my stock air filter and breather back on since they didn't know how much air the K&N filter/new air cover was letting in along with the Clayton Mod...this defeats my whole intention of letting the bike breathe. I hate to think I just wasted $200. in parts and labor. Please help. Thanks Tom O'Fallon, Illinois.

[Retro Rich]

Ok Tom, first off...your dealer's service department is obviously full of people that don't know what the heck they are doing. The Cobra jet kit...well, it is a waste of money and sorry to break the news to you. Your stock Main Jet (I hope they gave it back to you or you can get it back from them ASAP) is a Keihin 195; this equates out to a DJ 208. If you can get your dealer to explain why if you are taking in more air that you want to decrease the amount of fuel the carb is pumping through---then I've obviously got something to learn here. There isn't a main jet that is even close (they are DynoJet or DJ numbers on those jets) to a DJ 208 or 210 in that stage 1 jet kit.

Get the stock Keihin main back in there with the stock Keihin Needle (scrap that DJ needle IMHO or put it back in with the jet kit and try to sell the thing to the idiots at your dealership), I'd shim with the "Scar" method and use 2-3 shims. Just follow the instructions in his post. A/F should start at 2&1/2 turns. Stock Keihin pilot (which is a Keihin 55).

Your bike isn't running well since you have increased the amount of air, and decreased the amount of fuel. It runs better with the choke pulled a little because the "choke" on this bike is basically an enricher that dumps raw fuel in there into the carb. With the choke pulled a little, you're giving it the fuel it wants to get a more regular and adequate mixture of air/fuel.

Hope this helps.

RR

[VTX-Man]

Thanks for the info Scar.

[OrangeVTX12]

I just performed the "Scar" method on my '06 VTX C this morning and my hat is off to ya Scar!! Last week my pipes and Kury Pro-R showed up in the mail and I was anxious to put them on over my 4th vacation only to be let down by the fact that after installing both on my bike...it ran rich.:( After precisely doing everything in the above order ( including putting the stock jets back in the carb and throwing the ones that came with the Kury back into the container they came in) that Scar recommended, my machine runs like a dream. Before performing the "scar", you could pick black boogers after riding my bike with the Kury jets installed! ( I might be exaggerating a bit!) But now it is a whole different machine!!! Words can not describe how proud I am of how it is running now. I stumbled on to this web site bummed out looking for a resolution to my problem and if you are reading this for the first time and are thinking of doing anything else beside the "scar" method...FORGET IT. Do the "scar" and you will be thanking him as I am!!
Signed... ONE PROUD VTX OWNER - THANKS SCAR!:patriot:

[Scar]

Orange: Now that you have found this place, "stick around"... The people on this forum have a good time and there are plenty of "bike tips" to be had.

Glad the tuning process went well for you. :cheers:

[Subbie]

I dont know if anyone looks in this area anymore or not but here goes...... HELP!!! This is kinda weird. I have the biddy box mod and the kiwi mod. (pretty free flowing) I have 2 shims and the A/F is at 2 turns. My plugs are the problem. The right front plug looks like its running rich. The right rear is close to perfect. The left rear is (now get this) half perfect and half rich. The front left one looks good too. What to do?

[Scar]

I dont know if anyone looks in this area anymore or not but here goes...... HELP!!! This is kinda weird. I have the biddy box mod and the kiwi mod. (pretty free flowing) I have 2 shims and the A/F is at 2 turns. My plugs are the problem. The right front plug looks like its running rich. The right rear is close to perfect. The left rear is (now get this) half perfect and half rich. The front left one looks good too. What to do?

The various plugs througout the bike will look different.. so how is the bike running? That is the main thing, tune by performance... if you have a bunch of snowwhite plugs, then you have something to think about (lean).. but if there is some soot on the plugs then don't sweat it.. if there is some tan on the plugs.. don't sweat it... tune for performance.. most of the big boys (bigger engine builders) run around a 12:1 a/f ratio and most on these boards would think that is too rich... it just depends on which "school" you are coming from and what type of performance you expect and in what part of the power band.

Here's a dyno run that many would think is too rich, but the bike runs fairly good for a street bike http://www.maximum-suzuki.com/forums/index.php?action=dlattach;topic=61263.0;attach=264 3;image

[cubancowboy]

Scar .. you the man !!! After two different rejets(one when the pipes were done and one when my hypercharger was put on) my bike was running ok but always felt like it was missing something. After doing some research here on the site I decided to take the plunge and put everything back to stock and apply Scars technique. My bike which has a Kury Hypercharger Pro S and Hard Chrome pipes has never felt better. Very responsive through all the gears and just feels like whatever if was missing is now there. Scar .. hats off to you brother. You the man !!!!

[Subbie]

The various plugs througout the bike will look different.. so how is the bike running? That is the main thing, tune by performance... if you have a bunch of snowwhite plugs, then you have something to think about (lean).. but if there is some soot on the plugs then don't sweat it.. if there is some tan on the plugs.. don't sweat it... tune for performance.. most of the big boys (bigger engine builders) run around a 12:1 a/f ratio and most on these boards would think that is too rich... it just depends on which "school" you are coming from and what type of performance you expect and in what part of the power band.

Here's a dyno run that many would think is too rich, but the bike runs fairly good for a street bike http://www.maximum-suzuki.com/forums/index.php?action=dlattach;topic=61263.0;attach=264 3;image

The bike runs good but I had read that you should keep an eye on the plugs as well. Is that only true if they are white? (Lean) I had probably questioned too soon anyway because the plugs are all darker the two front ones are sooty and the back ones are dark brown after putting 200 more miles on the bike. Should I just let it ride if the bike is running well? :hmm2: BTW thanks for the wright up and the help here.

[Scar]

Subbie: Sounds fine the way you are describing things... go out and have some fune.

Cubancowboy: You are welcome.. glad things worked out for you.

[kurt_kemp]

ok, I have done a few things this week to the bike. First I removed the pair system per this sites suggestions and the bike ran fine. I then made a new air cleaner (biddy box) using a cone air cleaner I found at autozone an matching breather. I am also running Samson Warlords with baffles in them. Last night I did this carb mod with 3 shims since I am considering this a "heavy breather". The only thing I did not do yet is adjust the A/F screw. The bike runs like crap as it sits right now. Driveable but ugly actin'. Anyway, this A/F screw, I have big hands and I can't seem to get to this thing. Looking for some suggestions on this. I have tried the .22 casing and the bullet connector but I cannot get my hand in there to put enough force to loosen it. Any suggestions? Am I going to have to spring for the "real" honda tool for this?

Last question, how far off is this a/f screw with the stock setting? Just curious what it may be at now. Must be way off judging by the way it runs. I have verified I have no vacum leaks or kinked hoses, etc. I think it is all in the adjustment since I cannot get my paws in there. Is 3 shims ok or should I have done only two?

Thanks for any help as I am sure these questions are something youo all have heard a 100 times!

Kurt

[jlorange]

Hi All.... I'm new to the forum, not cycles though. question for anybody, is the carb tuning useful for all stock bike? got an '03 1300S, runs like crap when cold, if i pull the choke, it won't stay on, immediatly starts creeping back in. wondered if Scar's carb procedure will help?

[Scar]

ok, I have done a few things this week to the bike. First I removed the pair system per this sites suggestions and the bike ran fine. I then made a new air cleaner (biddy box) using a cone air cleaner I found at autozone an matching breather. I am also running Samson Warlords with baffles in them. Last night I did this carb mod with 3 shims since I am considering this a "heavy breather". The only thing I did not do yet is adjust the A/F screw. The bike runs like crap as it sits right now. Driveable but ugly actin'. Anyway, this A/F screw, I have big hands and I can't seem to get to this thing. Looking for some suggestions on this. I have tried the .22 casing and the bullet connector but I cannot get my hand in there to put enough force to loosen it. Any suggestions? Am I going to have to spring for the "real" honda tool for this?

Last question, how far off is this a/f screw with the stock setting? Just curious what it may be at now. Must be way off judging by the way it runs. I have verified I have no vacum leaks or kinked hoses, etc. I think it is all in the adjustment since I cannot get my paws in there. Is 3 shims ok or should I have done only two?

Thanks for any help as I am sure these questions are something youo all have heard a 100 times!

Kurt

With 3 shims in there, be sure that you have trimmed the tit under the needle holder cap.. that will cause problems if the needle does not have free movement.

If you find something that will fit into the hole of the "D" screw, then it must be "dented" a little and rotated until the dent slips in where the "D" is and then unscrew the needle.. now you know why (one of the reasons) that I recommend removing the needle the first time that you go in there and putting a notch in the head so it can be adjusted with a flat bladed screwdriver. -- Car radio antennas have also been used... also those "blue" wire/crimp connectors seem to fit over the "D" screw and work for a lot of people.

To make things easier to work on, loosen the hose clamps on the rubber intake manifold so the carb can be rotated slightly and it will make it easier to work on the A/F screw -- DON'T FORGET TO PUSH THE CHOKE KNOB IN after you have finished working... it will be pulled out a little from moving the carb body around.. it will give you headaches if you forget and the bike will run like crap (check it now in fact if you haven't before).

[Scar]

Hi All.... I'm new to the forum, not cycles though. question for anybody, is the carb tuning useful for all stock bike? got an '03 1300S, runs like crap when cold, if i pull the choke, it won't stay on, immediatly starts creeping back in. wondered if Scar's carb procedure will help?

Using the choke on this engine is a bad idea.. loads up the plugs really fast.. you might want to clean them up and start over again.

Your bike doesn't want to run when cold.. lean.. turn the A/F screw out maybe 1/8th turn.. not too much at a time... just a little does a lot.

When you start the bike, do not use the choke, but instead use the throttle to keep revs up to idle speed or a little above... it will eliminate a lot of problems... the choke really is a bad deal.

[jlorange]

Thanks Scar, i'll see if I can get to that A/F screw.

[kurt_kemp]

With 3 shims in there, be sure that you have trimmed the tit under the needle holder cap.. that will cause problems if the needle does not have free movement.

If you find something that will fit into the hole of the "D" screw, then it must be "dented" a little and rotated until the dent slips in where the "D" is and then unscrew the needle.. now you know why (one of the reasons) that I recommend removing the needle the first time that you go in there and putting a notch in the head so it can be adjusted with a flat bladed screwdriver. -- Car radio antennas have also been used... also those "blue" wire/crimp connectors seem to fit over the "D" screw and work for a lot of people.

To make things easier to work on, loosen the hose clamps on the rubber intake manifold so the carb can be rotated slightly and it will make it easier to work on the A/F screw -- DON'T FORGET TO PUSH THE CHOKE KNOB IN after you have finished working... it will be pulled out a little from moving the carb body around.. it will give you headaches if you forget and the bike will run like crap (check it now in fact if you haven't before).
Finally got the screw. Sheesh, those engineers obviously never had to take one out. Anyway, had to improvise. Small flathead screwdriver jammed into about a 8 inch piece of 1/8" clear gas line. I was able to thread the gas line screwdriver in the and twist the thing out. Once out I carefully modified the end of it with a "permanent" extension so I can just reach my hand in the and turn it. With all that put back together I will start fiddling with the actual adjustment tomorrow.

I did make sure the tit was trimmed far enough to let the main needle wiggle and I will check the choke tomorrow though I did not really move the carb around any. I'll post my anticiapted "success" story.

Thanks for the help!
Kurt

[Robin_Hood3570]

You may have just purchased a new exhaust and/or air intake and are wondering how you should "tune" the carburetor. First off if you just "fire the bike up" with the new parts installed, THE BIKE WILL RUN. Depending on how "free flowing" the aftermarket parts are that you installed the bike will run anywhere from "pretty good" to "pretty lean and very nervous", but it will run. So now the bike has to be TUNED. The easiest, least expensive, quickest, most predictable and fool proof method of rapidly tuning it would be to ADJUST the stock parts that are already in the carb. Some people venturing into the "mods" game want to do them all at the same time... this has OFTEN been proven to cause problems for the neuvo MC "wrench". DO NOT remove the PAIR system during the same session that you are tuning the carb. :nono: , it is common while working with the PAIR removal to "miss" something in the process and have an open vacuum line or "other" air leak. Many who have done both of these mods simultaneously have ended up fiddling with their carb for days/weeks on end chasing their tails looking for what went wrong with the carb tuning while all the time it was an error in the PAIR system removal. There have been some war stories spread about how difficult it is to tune a carburetor.. bull hocky! The most difficult part of tuning a carb on a VTX 1300 is removing the fuel tank for the first time and figuring out how to dissconnect the electrical connectors under the tank.

So, what comes first eh? REMOVE THE FUEL TANK. Follow the directions in the service manual.. everyone should have a service manual.. the money you save in THIS carb tuning process alone will pay for a service manual. The money you save doing your first valve adjust using the service manual would buy a nice set of tools that can be used in OTHER money savings projects... EVERYONE needs a service manual..

Next REMOVE the air filter and backing plate. I won't "get into" hooking and unhooking the hoses attached behind the backing plate, they are pretty straight forward and will become part of your "learning process" of the easiest ways to rapidly navigate through assembly/disassembly.

NOW the carburetor is EXPOSED. Sitting on top of the carb you will see the vacuum chamber cover. Remove the cover and then remove the compression spring under the cover. Now gently grab the diaphram/piston rubber and pull it out.. the Vacuum piston (slider piston is what most old timers call it) is attached to the diaphram and the whole package will come out with it. YOU ARE ALMOST DONE AND READY TO PUT THINGS BACK TOGETHER.. see, I told you.. removing the tank was the most difficult part of the process... unscrewing the 4 vacuum chamber cover screws was no big deal, right?
Look at the slider piston and you will see a tappered "needle" sticking out the bottom of it, that is the jet needle. Look inside the slider piston and you will see the Jet needle holder. The jet needle holder is next to be removed.. you will see in the center of the holder it will accept a Phillips head screwdriver which can be used to "unscrew" the cam locks, BUT the "best" method is to use a small socket and fit over the head of the "cap" and unscrew the cap... I'm thinking it's an 8mm.. difficult to recall those things sometimes at my age, but you'll discover the correct size. Twist the cap counter clockwise just as tho you were unscrewing any "standard" nut or bolt and you will feel a "pop" after making a very small motion.. that was the cams unlocking.. the cap can now be removed, it is "unlocked".

Under the needle holder cap there is a small spring "screwed" onto a plastic "tit" protruding from the bottom of the cap... well actually the "tit" has no threads, so the spring is not "screwed" on, but consider it so... instead of "pulling" the spring off and distorting it's shape, give a "light force" pull on the spring while unscrewing it from the "tit" and set the spring aside. The "tit" does not protrude very far, but it must be "trimmed" for "heavy breather" mods, so go ahead and trim it now even if you are doing a "light breather" tune... Take some TOENAIL clippers (those are the large ones, not to be confused with fingernail clippers) and "snip" the "tit" in half.. that should be enough for heightened needle raising and still provides enough remaining "tit" for the small spring to be screwed back onto... set the needle holder cap aside.

Remove the needle from the slider piston.. place your shims into the needle "point" and make sure they slide all the way to the needle head with the washer/shim hole big enough so free movement along the needle is achieved. Hold the slider piston in your left hand and turn it at an upwards angle and insert the needle INTO the slider piston hole, passing through the CENTER hole in the slider piston (this process will not work for "left handers", you will have to purchase a Yamaha carburetor). Face the slider piston DOWN and the needle should be hanging from the bottom of the slider piston and sitting "on" the shims/washers INSIDE the piston.

Take the SMALL spring that was unscrewed from the underside of the needle holder cap and screw it back onto the shortened "tit" under the needle holder. Put the needle holder cap into the slider piston with the small needle spring tensioner sitting on top of the needle head. (If the 8mm socket is placed onto the top of the needle holder cap "nut" the tension is enough to hold the cap.. the needle cap holder can be easily inserted into the slider piston with this method utilizing a socket extender). Twist the needle holder cap clockwise (even the left handers) as tho "tightening" and you will feel the cams lock into place... that's it, the needle holder is locked. If enough of the "tit" was trimed, this should be a relatively easy "twist"... Hold the slider piston with one hand and "wiggle" the needle with the fingers on the other hand... the needle should "wiggle" (movement), this assures true alignment into the emulsion tube :) . If the needle is "stiff" and won't "wiggle", then the "tit" was not trimed enough :nono: ... go back and trim more from the tit until free needle movement is achieved. (If you are using a DJ needle, the tit must also be trimmed for the same reasons)

Replace the diaphram spring onto the needle holder cap and replace the vacuum chamber cover.. NOTE: There is an irregular "shape" in the cap that must be matched to it's mating surface when remounting, this is what the manual calls the "tab and air passages"... "Snug" the vacuum cap screws and continue reassembly.

Under the carb is the A/F screw (see manual), the stock screw head requires a "D" type tool for adjustment. If you slightly dent the end of an empty .22 shell casing, this will fit into the hole and can be used to unscrew the "D" screw. Take the "D" screw completely OUT. On the top of the "D" screw head will be a spring followed by a washer and then an "O" ring.. save these parts and reasemble in the same order when putting the A/F screw back in.

While the A/F screw is OUT, use a hacksaw blade or some simular device to cut a thin channel into the head of the top of the "D" screw.. this slot or channel should be wide enough for a flathead screwdriver blade to fit into for A/F adjustment. Once the slot has be cut into the screw/needle head and the screwdriver blade fits, replace the spring/washer and "O" ring and replace the A/F needle into the needle jet hole and screw IN. Take your screw driver and screw in the needle until it LIGHTLY seats or stops turning ;) ... don't get anal about this and over tighten or damage could be caused to the needle/jet mating surfaces :( . If you error on "seating", error on the LOOSE side, final tuning will not be affected by a minute discrepancy of "seating" at this stage of tuning. Turn the A/F screw OUT 2 1/2 turns with the screwdriver.

Reassemble the airbox and fuel tank.

Before firing the engine, look at the CHOKE KNOB and push it in all the way... any flexing of the carb while working on it will flex the choke cable and pull the choke out... it will not run properly with the choke pulled out AT ALL and final tuning cannot be achieved.

Shim heights:
"Open" style airbox and aftermarket "free flow" pipes... usually about 2or 3 shims.
Airbox flowing more air than stock design, but not in the "heavy breathing" class and/or pipes either free flow or somewhat restricted... usually about 1or 2 shims
Stock airbox (K&N filter in stock box is still "stock") and after market pipes... usually 0 or 1 shims
Stock airbox and stock pipes... tune the A/F screw for maximum performance...

A/F settings:
While determining proper main jet circuit settings the A/F screw should be set at 2 1/2 turns and NO adjustments made to it until the high speed circuit has been properly tuned -- Turning the screw IN leans the mixture... turning the screw OUT richens the mixture -- Fine tuning the A/F screw should be done in no more than 1/8 turn increments... very fine tuning will be even less... it is highly recommended to "slot" the "D" screw and tune the A/F screw with a screw driver... a 90 degree drive is useful if you have one... improvise.

SLIDER PISTON SPRING:
That's what I call the big spring directly under the vacuum cap and sitting on the needle holder cap. -- Most tuners that have springs of the type found in the VTX carb shorten the spring for faster throttle response... this is not necessary for the bike to operate, but you will shorten the response time if you shorten it... I would not recommend shortening it past 5 1/16"... that is the lenght of the shorter DJ kit supplied spring and is a proven entity... The Keihin spring is of slightly larger diameter wire so a "safe" fudge factor is built in if you cut it to 5 1/16", most do... you can cut it less than that if you are nervous, but you shouldn't have any problems with 5 1/16"... place the cut end DOWN into the slider piston and resting on the needle cap... uncut end UP against the vacuum cover.. that is the "common" practice (and no bannanas on boats either).

Most any needle design or jet design will work with the Keihin carb as long as they are set to the proper height and have the correct diameter... It has been my findings that the stock Keihin needle and jet work more "smoothly" if properly shimmed than some other designs because of the needle design and large diameter jet size... The Keihin design is just more forgiving and not as "touchy" as some other designs and need I say you are not required to remove the float bowl cover to change main jet sizes?... The Keihin 195 main jet suits most all purposes... if you require more than that you are past the "beginning" tuner stages and in that case you might think about a Keihin 200 or 205 (DJ equivalents of 213 and 218)... I don't think more than a 205(/218) would be required by anyone unless cam, piston, valve and porting changes have been made... in which case I would like to communicate with you on your engine mods and findings... you most likely won't require any "advice", but I would like to hear about extensive engine mods... mine will retain the stock configuration... I have a 1200cc street fighter for speed.

Have fun and if I am "not around" to answer any possible questions (I have a somewhat irregular schedule at times), I would recommend asking Retro Rich.. He has a mechanical mind and a healthy grasp on the tuning philosophy.

Radio Shack Shims:
Radio Shack Part # 64-3022
Package of 100
Steel Flat Washers
20 each: #2, #4, #6, #8, #10

They are in the Hardware section of the store -- In the plastic pull out trays that are divided into sections.. Plastic bag... Looking at the bag I would say we are using the #4 washers.. anyway it is the second from the smallest... we "miched" em several years ago and can't recall, they are like 0.019 or 0.020 or pretty close to that neighborhood.. they work! -- Oh yea, they now cost $1.99/pkg -- inflation.

Any "washer/shim" of similar thickness (0.020") with a hole big enough for the needle to comfortably slide through and small enough for the needle head to sit on will work just fine.

I could write another entire page on "tuning techiques", but it has already been done in what I consider a comprehensive and accurate manner... use it as your tuning Bible -- Factory Pro http://www.factorypro.com/tech/carbtun.html

Don -- AKA "Scars" :cheers:
Scar..need help on my carb 38MM cv Honda VTX 1300R...have installed vance and hines curizer pipes and bought a Kurankyn pro series hypercharger....and a Dynojet kit for the pipes...here is the problem...DJ tells me to install a Dj #185 on the groove #5 and 3.5 turns on the A/F screw, with the stock spring reinstalled..(K) people tell me change the following Pilot jet to #65, Main jet #185, shim the stock needle with a 0.8 shim included in their kit...so what do I do here to get this bike up and running....what parts do I use and at what settings? ..I do really need some help here and in detail please.

[Scar]

Scar..need help on my carb 38MM cv Honda VTX 1300R...have installed vance and hines curizer pipes and bought a Kurankyn pro series hypercharger....and a Dynojet kit for the pipes...here is the problem...DJ tells me to install a Dj #185 on the groove #5 and 3.5 turns on the A/F screw, with the stock spring reinstalled..(K) people tell me change the following Pilot jet to #65, Main jet #185, shim the stock needle with a 0.8 shim included in their kit...so what do I do here to get this bike up and running....what parts do I use and at what settings? ..I do really need some help here and in detail please.

If you follow the Kury instructions you will be hating life.. ask others that have traveled that route.

Install 2 radio shack shims under the stock Keihin needle.. trim the tit under the needle cap holder.. it's all in the instructions above.. A/F screw 2 1/2 turns out.. your choice on cutting down the diaphragm spring.. if you cut it to about 5 1/16" then the throttle response will be quicker.. worst case scenerio is you use 3 radio shack shims.. depending on elevation and other minor variables..

Ask those on the main board about using the Kury kit and if anyone has had "luck" with this technique.. just follow the directions.

:cheers: :cheers: :cheers:

[OrangeVTX12]

Take Scar's advise Robin_Hood. I installed the pro R on mine with the Kury kit and it wouldn't run at all and barely would even idle. Read about the Scar method on this website as a last resort and followed it to the T and have been runnin proud since. You can learn a lot of great things out here. The nicest thing about it, is it's full of people who have been right where you are and the info. you get is accurate. You will have to make slight adjustments that cater to your bike like the adjustment on the AF. Mine was 1/8 turn in do to running a little rich but now it's perfect. This method does nothing but work!

[Dream VTX]

I have been looking for this post so i can bow down and worship at the alter of SCAR..... my first purchase was the hyper charger pro and with the longshots the bike was already running way rich and when i installed the hyper it didnt want to run at all , a horrible most deffinatly non VTX like performance..... a little bit of patience wrenc time and several grease coveredcopies of the scar method later , my bike runs fantastic and doesnt foul out the plugs every 3 weeks as before. I cannot thank you enough ....
I have a question though , the performance is alot better than when i originally gor the bike , im pulling 14.2 in quarter mile ( 250lb rider) so im
very please but would like to know if that number is comparible to what any one else is seeing with similar mods? thanks again for all the help
Dave

[Scar]

I have been looking for this post so i can bow down and worship at the alter of SCAR..... my first purchase was the hyper charger pro and with the longshots the bike was already running way rich and when i installed the hyper it didnt want to run at all , a horrible most deffinatly non VTX like performance..... a little bit of patience wrenc time and several grease coveredcopies of the scar method later , my bike runs fantastic and doesnt foul out the plugs every 3 weeks as before. I cannot thank you enough ....
I have a question though , the performance is alot better than when i originally gor the bike , im pulling 14.2 in quarter mile ( 250lb rider) so im
very please but would like to know if that number is comparible to what any one else is seeing with similar mods? thanks again for all the help
Dave

From the time slips that I've seen posted I would say you are "in the ballpark".. especially at 250... some of the slips I've seen were from guys that the wind would blow away :) -- I've never ran the "X" in the quarter myself.. strictly a cruiser for me.. well, except for blowing away $25K HD's that are trying to show off, but that really doesn't count.. I do have an inline 4 street fighter that is pretty fast tho :cheers:

[EFSandberg]

I just bought this very nice 07 VTX1300 with a set of Cobra pipes on it and noticed that it had this flat spot in the mid range, and stumbled during certain phases of acceleration. With a bit of web searching I found the SCAR method. I took out the cobra jet kit, put the stock jet back in along with the stock needle with 2 shims under it (they measured .018 thick each) and dialed out the AF needle to 2 and 1/2 turns from its full closed position. I took all the plugs out and cleaned them up in the blaster since the bike was running so rich that they were covered with carbon deposits.
This seemed to have done the trick, no more flat spots and the bike no longer stumbles during all phases of acceleration.
One thing I did find is that getting the bowl off the bottom of the carb is much easier if you loosen the carb from the manifold so you can tilt it out a bit and be able to get to the philips head screws.
Other than that is was about a one hour turn around for this job based on scar's will documented instructions.

[Scar]

I just bought this very nice 07 VTX1300 with a set of Cobra pipes on it and noticed that it had this flat spot in the mid range, and stumbled during certain phases of acceleration. With a bit of web searching I found the SCAR method. I took out the cobra jet kit, put the stock jet back in along with the stock needle with 2 shims under it (they measured .018 thick each) and dialed out the AF needle to 2 and 1/2 turns from its full closed position. I took all the plugs out and cleaned them up in the blaster since the bike was running so rich that they were covered with carbon deposits.
This seemed to have done the trick, no more flat spots and the bike no longer stumbles during all phases of acceleration.
One thing I did find is that getting the bowl off the bottom of the carb is much easier if you loosen the carb from the manifold so you can tilt it out a bit and be able to get to the philips head screws.
Other than that is was about a one hour turn around for this job based on scar's will documented instructions.

:cheers: :cheers: :cheers:

[baumgardner]

Hey Scar,

I Have just installed the Cobra Speedster Shorts ( no baffs ) , and have the Kury Pro-R sitting in the garage , just wondering if you could tell me or if anyone else has the same set up and new what exactly was needed as far as shims and tuning , i understand that every bike will be different and location matters too but just to get me started , i just need a little help!

[tireman43]

Hey Scar,

I Have just installed the Cobra Speedster Shorts ( no baffs ) , and have the Kury Pro-R sitting in the garage , just wondering if you could tell me or if anyone else has the same set up and new what exactly was needed as far as shims and tuning , i understand that every bike will be different and location matters too but just to get me started , i just need a little help!


In one of the above posts(about 4 up) Scar recommended 2 shims. It was a similar situation with pipes and a Kury. That would be the start point. Good luck.

[Scar]

Hey Scar,

I Have just installed the Cobra Speedster Shorts ( no baffs ) , and have the Kury Pro-R sitting in the garage , just wondering if you could tell me or if anyone else has the same set up and new what exactly was needed as far as shims and tuning , i understand that every bike will be different and location matters too but just to get me started , i just need a little help!

"Most" with your setup end up running three shims under the needle head.. You can either start with three or with two.. two "may" be lean and for begining tuners it is easier to recognize a lean condition rather than a "fat" (rich) condition and then work your way to fatter (one more shim).. The choice is yours and like you said, "it varies slightly from bike to bike and from area (elevation/humidity/temperature) to area... -- Don't forget to trim the tit under the needle holder cap and all should be good... whether you start with 2 shims or 3 shims and 2 1/2 turns on the A/F screw the bike will run better than it has before.. it's just a matter of "fine tuning" after that.. if you want to quicken the throttle response time you can also cut the carb slider piston spring down also (diaphram spring... called different things in different tuning groups)..

Have fun -- Don

[Scar]

In one of the above posts(about 4 up) Scar recommended 2 shims. It was a similar situation with pipes and a Kury. That would be the start point. Good luck.

Thanks Tireman... that is the general "formula"... some may end up with three shims, but I like starting new tuners at 2 shims (and sometimes the conditions for that area end up being 2 shims) because it is so much easier to diagnose a lean condition if the bike is not "totally" on when first beginning the tuning process... it is true that a seasoned tuner can also readily identify a fat condition, but almost anyone can identify a lean condition (a "nervous" state of tune) as opposed to the "fat"/lethargic "blubber"...

[baumgardner]

thanks a lot i plan to start tomarrow so i may be back for some more questioning , i appreciate the help im very new to workin on bikes and stuff !

[jdr2dr]

Thanks Tireman... that is the general "formula"... some may end up with three shims, but I like starting new tuners at 2 shims (and sometimes the conditions for that area end up being 2 shims) because it is so much easier to diagnose a lean condition if the bike is not "totally" on when first beginning the tuning process... it is true that a seasoned tuner can also readily identify a fat condition, but almost anyone can identify a lean condition (a "nervous" state of tune) as opposed to the "fat"/lethargic "blubber"...

Scar
I have been reading this WHOLE section, I just purchased and put on Sidebuners for my 05 VTX 1300C --- I have a stock air box and plan for the time being keeping it... Washers on the Airbox to open it up?

I assume the bike is running lean after the pipes added, runs ok, (seems like your outline describes my bike to a tee now) but not like the stock pipes... I plan to start with 2 shims on the needle and 2.5 turn out on the AF screw (is that the pilot screw - my manuel speaks about) as for cutting the tit should I cut it about half as you state in your mod outline? Is cutting the tit proportional to number of shims that you use?

Been turning wrenches all my life, have to admit this is the first time inside the carb, so I am a bit skeptial as to how it will come out...

Thanks for your write up and will post as to the outcome of this mod for me...

Jim:hmm2:

[Scar]

Scar
I have been reading this WHOLE section, I just purchased and put on Sidebuners for my 05 VTX 1300C --- I have a stock air box and plan for the time being keeping it... Washers on the Airbox to open it up?

I assume the bike is running lean after the pipes added, runs ok, (seems like your outline describes my bike to a tee now) but not like the stock pipes... I plan to start with 2 shims on the needle and 2.5 turn out on the AF screw (is that the pilot screw - my manuel speaks about) as for cutting the tit should I cut it about half as you state in your mod outline? Is cutting the tit proportional to number of shims that you use?

Been turning wrenches all my life, have to admit this is the first time inside the carb, so I am a bit skeptial as to how it will come out...

Thanks for your write up and will post as to the outcome of this mod for me...

Jim:hmm2:

Jim: Cut the "tit" about in half.. yes.. leave enough so the spring will not slide off of it -- after the needle is installed in the black plastic piston and the needle holder cap is twisted (locked) into place you should be able to wiggle the needle a little from side to side.. that is all that is required/free movement.

With a stock airbox you will only need 1 shim or no shims.. 2 shims should make the bike too rich, even at sea level. -- Yes, the pilot screw is the A/F screw.

Have fun.

[jdr2dr]

Jim: Cut the "tit" about in half.. yes.. leave enough so the spring will not slide off of it -- after the needle is installed in the black plastic piston and the needle holder cap is twisted (locked) into place you should be able to wiggle the needle a little from side to side.. that is all that is required/free movement.

With a stock airbox you will only need 1 shim or no shims.. 2 shims should make the bike too rich, even at sea level. -- Yes, the pilot screw is the A/F screw.

Have fun.

Got her Done! Really not a bad process. The hardest part for me was cutting the top of the AF screw - it seem to be fighting me. Then re-connecting the hoses on the airbox was the second hardest part. (hands too big I guess) Had the tank off before when I installed a tach that was a piece of cake...

Needle has good movement - I used 1 shim - 2.5 turns on the AF screw... the bike runs better than when I bought it...

Now I am gearing up for the popping sound in the pipes with a removal of the PAIR system... Going to do that when the cover blanks get in - ordered them today...

Really appreciate your effort in all this, bike is sounding GOOD and running better... thanks...:choppersm

[Scar]

bike is sounding GOOD and running better... thanks...:choppersm

:cheers::cheers::cheers:

[miclea0317]

I am serching for some expert advice. I have cobra speedster shorts, pair valve removed, APC filter biddy box, and Scar method. The bike seams to run fine except I get a low tone backfire (souds like a loud potato gun) on decel from about 55 mph and above. It usually just one backfire on each decel. I have 3 shims and about 3 1/2 turns on A/F. If anything the bike seems a little rich. The air temp in North Carolina has been between 40 - 65 degrees. Warmer air seams to help alot. I didnt want to re- jet because I am hoping when it gets hot and humid soon this problem will go away. Just wondering if this sounds like I need to change the pilot jet and should I do it even though it will be hot soon? Thanks guys

[boog]

Gentlemen,
First let me say thank you for all the good info on this website I enjoy reading all the posts and tricks you all have.
I already did the Scar method and when i started the bike today I reved it and still had a little black smoke coming from the exhaust. I have the stock box with k&n with cobra dragsters. I am wondering if that is normal or is the a/f scre still need some tuning? I know it is going to be better when i ride it but just freeks me out to see the hint of black smoke still. I appreciate the help.
Semper Fidelis
Boog

[Scar]

I am serching for some expert advice. I have cobra speedster shorts, pair valve removed, APC filter biddy box, and Scar method. The bike seams to run fine except I get a low tone backfire (souds like a loud potato gun) on decel from about 55 mph and above. It usually just one backfire on each decel. I have 3 shims and about 3 1/2 turns on A/F. If anything the bike seems a little rich. The air temp in North Carolina has been between 40 - 65 degrees. Warmer air seams to help alot. I didnt want to re- jet because I am hoping when it gets hot and humid soon this problem will go away. Just wondering if this sounds like I need to change the pilot jet and should I do it even though it will be hot soon? Thanks guys

Yes, the system is lean. A factory pro series 393 #205 or 210 mainjet would most likely help a lot... the biddy box sucks in a lot of air.. as much as a bak system.. and the cobras will get ride of everything demanded of them.

The reason that you have less backfiring when it warms up is because cold air is denser than warm air and therefore when it is cooler you intake is supplying more air per cu. in. to the combustion chamber.. I would go ahead and "jet up" a little if it is bothering you.. check the plugs and see what you think.. -- btw 3 1/2 turns on the A/F screw is way too much.. this is an indicator that you REALLY need a larger main jet... you could also order a series 21 #58 pilot jet at the same time as ordering the main jets and save on shipping... main jets are about $3 apiece and pilot jet about $5 apiece.. you may not require the 58 pilot jet and I would not install it right away... just turn the A/F screw back to 2 1/2 turns and install the 205 main jet and 3 shims and see how you like it.

[Scar]

Gentlemen,
First let me say thank you for all the good info on this website I enjoy reading all the posts and tricks you all have.
I already did the Scar method and when i started the bike today I reved it and still had a little black smoke coming from the exhaust. I have the stock box with k&n with cobra dragsters. I am wondering if that is normal or is the a/f scre still need some tuning? I know it is going to be better when i ride it but just freeks me out to see the hint of black smoke still. I appreciate the help.
Semper Fidelis
Boog

With the stock box and K&N and cobras you should be using about 0.02" shim (one radio shack shim) and about 2 1/2 turns on the A/F screw.. that will get you pretty close... You have to run the bike for at least 15 miles on the highway to get it up to a reasonable "operating temp" and then make your judgements about how the bike is running and what fine tuning may then be needed... when you get it to pull good on the top end after running like that and the bottom end seems fine, then you are tuned.. don't worry about the black smoke at ignition time..

Semper Fi

[boog]

Thank you Scar I will give it a try. I had it out today just down the street and back total about four miles and i noticed a little backfire but maybe just me trying to find something wrong. I appreciate the reply.

[EddieTN]

I have a 2007 1300 Retro. I put the Vance and Hines Big Shots on my bike with Jet Kit, after putting jet kit in it wouldn't run well at all. But after reading Scar's article, I put the Original Jet Kit back in and turned the A/F 2 1/2 turns and it runs perfect. Thanks for the advise.....

[philallemang]

Got some jetting questions? I have HK 2.5 classic straights on my 1300 with a stock air box. I bought the bike this way so I had no idea what is in it for jets. The bike is currently running good which is set at 4 on the clip, no shims under but there was one shim on top! Also has a aftermarket shorted spring.

So whats the deal? Did some just put the extra shim on top so they didn't lose it? What do you expert carb techno's think i should be running? There also could be a different needle cause of the shorted spring and can a guy tell if its not a stock needle?

Thanks again guys:)

[Scar]

Got some jetting questions? I have HK 2.5 classic straights on my 1300 with a stock air box. I bought the bike this way so I had no idea what is in it for jets. The bike is currently running good which is set at 4 on the clip, no shims under but there was one shim on top! Also has a aftermarket shorted spring.

So whats the deal? Did some just put the extra shim on top so they didn't lose it? What do you expert carb techno's think i should be running? There also could be a different needle cause of the shorted spring and can a guy tell if its not a stock needle?

Thanks again guys:)


The needle has "notches" and an "E" clip (that is the clip that slides into
the notch and regulates the needle height..) it is not a stock needle.. the washer on top of the needle can be removed and stored in your tool box.. chances are that the needle in a dyno jet needle and a shortened dyno jet spring.. who knows what jet is in there, but if the bike is running good, it doesn't matter.

Have fun

[boog]

With the stock box and K&N and cobras you should be using about 0.02" shim (one radio shack shim) and about 2 1/2 turns on the A/F screw.. that will get you pretty close... You have to run the bike for at least 15 miles on the highway to get it up to a reasonable "operating temp" and then make your judgements about how the bike is running and what fine tuning may then be needed... when you get it to pull good on the top end after running like that and the bottom end seems fine, then you are tuned.. don't worry about the black smoke at ignition time..

Semper Fi

Scar,
I ran the bike for a while and it is good although I hear some sounds like some cracklin and a minor popping sound from the original one shim and 2 1/2 turns. What do you suspect that may be? I am confused on the A/F screw, turning it out makes the bike run rich and in makes it lean. Now with the popping and crackling I need to go.....? I appreciate it.
Another thing about the pair valve removal, how hard is this mod and is it the same as posted on the 1800? I only have been riding with the new pipes and adjustments for about oh 30 miles and i got to get that decel crap sound out of here. I wanted to get the carb set up first before i start on the pair valve removal. Thanks for all the help.
Boog

[Scar]

Boog: Sounds like you have it tuned "pretty close" right now..
tune for performance, not sound.. you will notice a change in
exhaust note, even at idle with various stages of tune.. but
performance tuning is what you really want..

"gurgle".. the gurgle is the sound being made by the PAIR valves still in place.
There is also some "crackle" sound produced by the PAIR valves.. it
was always there, but much easier to hear with the less restrictive
exhaust pipes installed. -- Yes, the PAIR valve removal it basically
the same as on the 1800 -- if you haven't removed PAIR systems before
then you may want a photo version of the actual 1300 to follow however
(make it a little easier).. go to the 1300 forum and post a new thread
"PAIR valve removal?".. Charlie or someone most likely has a link to
the 1300 removal.. request that specifically.. it is out there.. I have
seen it, but never saved it because I have removed several PAIR systems
from various brands/models of bikes and am somewhat familiar with the "concept".


Go ahead and ride the bike the way it is while you are waiting for the
block-off plates.. sounds like you have it pretty good right now.
(By the way.. no matter what you are "thinking".. turning the A/F screw OUT
does richen the mixture and not lean it out.. for some reason it is giving
you a "head fake" and making you think it is getting leaner..).. If you cut
the notch in the head of the A/F screw and use a flat bladed screwdriver to
adjust the A/F screw then there is no question as to where you are and it
is very accurate.. using the "D" tool on the stock configuration can be
much more inaccurate.. there is slippage.. tool rounding and a multitude
of things that can cause inaccurate adjustments that way..

:coffee:

[boog]

Scar,
Once again thank you. I am just a little OCD and fail to realize sometimes it is a machine and I cant always dictate what it will do. It is set up pretty good as you have said twice now and that is it I will leave it. I know I am close enough not to worry about it. What would be the difference if any if I took the baffles out of the pipes, i want them louder, do i need to change anything?
On the other topic when the bike is rich it means too much fuel and not enough and vice versa for running lean. Am i correct on that one. That is what I was thinking anyway. I will leave you alone now but man I appreciate all this help and making me smarter in the world of tuning and performance. Thank you Sir.
Boog

[Scar]

Boog: Yes, rich is more fuel -- lean is less fuel.. we also call rich, "fat"..
if you run into any tuners that have been doing it for awhile, they will call it "fat".

Exhaust and baffles -- You are opening up a can of worms now.
If you just want more sound, then remove them.. if you want more performance it is a crap shoot from exhaust system to exhaust system.. depends on the original design. I have Rinehart pipes on my "X".. those pipes were built by a premier NASCAR exhaust builder (over 80% of NASCAR runs Rinehart produced pipes).. the way he does it is to get an "X" engine, put it on a dyno and design a pipe around the engine performance (with NASCAR engines he takes the ACTUAL engine from the car.. it costs a lot more.. but the "boys" are willing to pay for a winning car) ..

The Rinehart drag pipes are three stage (three different sizes of pipe from the header to the exhaust tip) -- The pipes pull quit well from the bottom end to the top end.. In the case of these pipes the price reflects the performance.. I bought mine for a little under $600 a few years back from an outlaw biker outlet.. I looked at the pipes recently and they are considerably more now.. but I stray from the topic. I also have an inline 4, 1200cc street fighter.. a friend of mine had one just like it and we wanted to see how much we could get out of the engine without spending any money.. First thing to do was to modify the airbox and then the stock exhaust.. I did a series
of exhaust mods over a period of about 1 1/2 years and tuned the intake each time for maximum performance (4 carbs/CV).. once I had what I thought was "max" out of the system I then got an exhaust system built by another guy that I know who builds exhaust among other things
(kinda like Rinehart)(this particular person holds a whole pile of national drag records on motorcycles.. he builds them).. the exhaust was built with an engine like mine running on his dyno.. took some time for him to get the perfect power curve (but then he had the formula for that engine and could and did reproduce them for the masses.. I got one of those).. anyway
when I put his pipe on I could notice a little more power in the mid range of the powerband than with the pipe I had modded over a 1 1/2 year time span.. there is only so much you can do with a "stock pipe" configuration... My other friend who modded his stock pipe virtually gutted it (more than I had mine).. His bike was fast, but a real pita to tune.. there was about a 3500 RPM window that it performed best and the rest were compromises.. so you had to tune it for the "area" that you planned on doing most of your "serious" riding.

Anyway.. I then put air pods on the bike (they are in a protected "air" area on that bike) and there was really no difference in performance between a highly modded stock airbox and full blown racing pods.. but there are major differences in exhaust systems.. it gets down to "flow design" and one of those parameters is controlling back pressure and exhaust velocity in various stages of the power band..

What the hell am I getting at?? I don't know about YOUR particular exhaust.. some exhausts can be helped in performance by removing baffles and some require baffles for the proper exhaust pressures.. Some companies design their exhausts with some "performance gains" and others "just for looks or sound"... I know of no one that mass produces an exhaust for
the "X" that will perform better than a Rinehart..

You can remove your baffles just for the "sound" and live with the results.. tune the bike for the difference in no baffles and see how you like it.. if you don't then you can replace the baffles -- or if sound is the objective, you can run it with or without baffles depending on which sound you prefer and the bike will still run pretty good... bottom line it is still a "cruiser" and an off the showroom floor crotch rocket will blow the doors off it anyway, so don't get too involved into the tuning for the race aspect unless you are a true gearhead.. and if you are there is no hope for you anyway.. hahahahaha

Hope that helps.. and don't worry about asking questions.. you get what you pay for and I am pretty cheap... hahahaha

[Kidd]

I dont know if anyone looks in this area anymore or not but here goes...... HELP!!! This is kinda weird. I have the biddy box mod and the kiwi mod. (pretty free flowing) I have 2 shims and the A/F is at 2 turns. My plugs are the problem. The right front plug looks like its running rich. The right rear is close to perfect. The left rear is (now get this) half perfect and half rich. The front left one looks good too. What to do?

I've been adjusting the carb a lot. One plug nice and brown...and the other black.
I'm going to put in a new set of plugs and ride it about a 100 miles and check again. If you have been making a lot of adjustments it's going to take some miles to get an idea of what's going on.

:choppersm

[BulldogChief]

Ok, we got a 2004 Honda VTX 1300S. I put Vance and Hines Stagger Shots and Kuriyakin Pro SeriesR Hypercharger on it. Ran rough so I removed the PAIR system and blanked the openings on the cylinder heads. Found you guys here and printed out Scar's carburetor mod. Did the mod except for the A/F screw (gonna plead ignorance here and ask if the A/f is the same as the "pilot screw" the manual talks about?

Got 2 shims on the needle and the stock #195 jet. Bike idles fine but still running like total crap on the road and falling flat on its face. When I twist the throttle when in gear, the bike hesitates and the motor wants to die like there aint no fuel gettin in there.

Any thoughts???????

[Scar]

Ok, we got a 2004 Honda VTX 1300S. I put Vance and Hines Stagger Shots and Kuriyakin Pro SeriesR Hypercharger on it. Ran rough so I removed the PAIR system and blanked the openings on the cylinder heads. Found you guys here and printed out Scar's carburetor mod. Did the mod except for the A/F screw (gonna plead ignorance here and ask if the A/f is the same as the "pilot screw" the manual talks about?

Got 2 shims on the needle and the stock #195 jet. Bike idles fine but still running like total crap on the road and falling flat on its face. When I twist the throttle when in gear, the bike hesitates and the motor wants to die like there aint no fuel gettin in there.

Any thoughts???????

A/F screw is same as pilot screw.

Sounds like you have an open/leaking vacuum hose... most common one is between the petcock and the carb there is a vacuum line.. when the pair system is unhooked there is then and "open" "T" connector.. either eliminate the connector and install a longer hose... install a straight through connector in place of the "T" connector OR put a vacumm cap over the open "T" that used to go to the pair system.

If that isn't it, there may be a loose vacuum line somewhere else in the system OR the vent hose from the fuel tank may have a kink in it.. several people have had that for some reason... the vent line is the one on the right side of the tank back towards the rear of the tank..

Odds are it is the "T" tho.

Bike should run on 2 shims with your setup.. get it running first... after that if it is lean from 60mph and up, add another shim...

[jdr2dr]

Ok, we got a 2004 Honda VTX 1300S. I put Vance and Hines Stagger Shots and Kuriyakin Pro SeriesR Hypercharger on it. Ran rough so I removed the PAIR system and blanked the openings on the cylinder heads. Found you guys here and printed out Scar's carburetor mod. Did the mod except for the A/F screw (gonna plead ignorance here and ask if the A/f is the same as the "pilot screw" the manual talks about?

Got 2 shims on the needle and the stock #195 jet. Bike idles fine but still running like total crap on the road and falling flat on its face. When I twist the throttle when in gear, the bike hesitates and the motor wants to die like there aint no fuel gettin in there.

Any thoughts???????


What SCAR said +++ -- did you pull the reed valves off the plates and use the plate that the reed valve was attached to as a gasket before you put your blocks on? That opening should be sealed with the gasket plate under your blocks...

Jim (just a thought)

[BulldogChief]

A/F screw is same as pilot screw.

Sounds like you have an open/leaking vacuum hose... most common one is between the petcock and the carb there is a vacuum line.. when the pair system is unhooked there is then and "open" "T" connector.. either eliminate the connector and install a longer hose... install a straight through connector in place of the "T" connector OR put a vacumm cap over the open "T" that used to go to the pair system.

If that isn't it, there may be a loose vacuum line somewhere else in the system OR the vent hose from the fuel tank may have a kink in it.. several people have had that for some reason... the vent line is the one on the right side of the tank back towards the rear of the tank..

Odds are it is the "T" tho.

Bike should run on 2 shims with your setup.. get it running first... after that if it is lean from 60mph and up, add another shim...

That's what I thought was a vacuum leak, gonna check it out this afternoon after work. THANKS!:cheers:

What SCAR said +++ -- did you pull the reed valves off the plates and use the plate that the reed valve was attached to as a gasket before you put your blocks on? That opening should be sealed with the gasket plate under your blocks...

Jim (just a thought)

Jim, yeah, I drilled out the reed valves, cleaned em up and put em back in then used the blanking flanges I ordered for them. So far Scar and CharlieD have said the same thing and confirmed my thought it's a vacuum leak somewhere.

I'm gonna go get some vacuum hose from the AutoZone and replace all the vacuum lines with new stuff. If that don't fix it, I am gonna have to bring it to the shop...really don't wanna do that. :nono::mad:

Thanks for all the help!!!!

[jdr2dr]

That's what I thought was a vacuum leak, gonna check it out this afternoon after work. THANKS!:cheers:



Jim, yeah, I drilled out the reed valves, cleaned em up and put em back in then used the blanking flanges I ordered for them. So far Scar and CharlieD have said the same thing and confirmed my thought it's a vacuum leak somewhere.

I'm gonna go get some vacuum hose from the AutoZone and replace all the vacuum lines with new stuff. If that don't fix it, I am gonna have to bring it to the shop...really don't wanna do that. :nono::mad:

Thanks for all the help!!!!

The two larger lines that come from the vaccume valve to the reed plates are easily removed - I pluggged the one back to the air box, and the smaller one that goes back to the "T" -- Going back to the shop sounds scarry... :-)

Jim:choppersm

[BulldogChief]

The two larger lines that come from the vaccume valve to the reed plates are easily removed - I pluggged the one back to the air box, and the smaller one that goes back to the "T" -- Going back to the shop sounds scarry... :-)

Jim:choppersm

When I removed the PAIR pump, I took out the hoses an everything. Installing the hypercharger had me plug one hose from the airbox but it was the one that went to the PAIR pump. There is another large hose that comes out of the front cylinder head just to the right of the reed valve that went to the airbox and now is going to the hypercharger. The vacuum line needed for the hypercharger is coming off the "T" and there is another hose on the rear of the hypercharger as well, I think it is a breather.

[Ken_r_mer]

bought an '04 vtx 1300 c that has vance/hines exhaust and k/n filter in stock air box. noticed after getting home from picking it up that the seller had the choke not fully "off" when idled warm. with choke fully off, bike idle died. I tried turning "up" the idle knob under the intake box with no change in idle speed. is there a starting point for the idle setting...like listed above for the pilot screw? air altitude is 1200 feet above sea level...if that makes a difference.

[jdr2dr]

your set up sounds like mine... My 05 was a bit lean at the start - they say all vtx's are a bit lean (thought mine was a bit more lean than normal, I am at 200' here in SoCal - had it in Idaho last Summer at 2200 feet, still ran great)... I did the SCAR mod 1 shim - 2.5 turn out on the A/F screw - K&N filter Stock A/B and it runs great... on a cold Morning I use the choke after it starts I push it in almost all the way and when it warms about a min. I push it all they way in... Runs great, idle is great, about 900 rpm (I installed a Baron tach)

Jim

[Ken_r_mer]

In the '04 1300c I just bought w/ vance/hines and a stock box with a k/n filter, it has a needle with 7 grooves and the "e" clip set in the 3rd groove from the end. I'm assuming that is a jet "kit" needle? What is the normal height for the "tit" inside the slider piston? I want to be sure the "tit" was cut per the previous instructions. No shims were found. If I were to add one shim, it goes between the "e" clip and the piston? Want to do this right the first time.

[BulldogChief]

When I removed the PAIR pump, I took out the hoses an everything. Installing the hypercharger had me plug one hose from the airbox but it was the one that went to the PAIR pump. There is another large hose that comes out of the front cylinder head just to the right of the reed valve that went to the airbox and now is going to the hypercharger. The vacuum line needed for the hypercharger is coming off the "T" and there is another hose on the rear of the hypercharger as well, I think it is a breather.

The vacuum hose lines look good, no cracks or leaks as far as I can tell. The tank vent hose is not kinked in any way. I am trying to get the A/F screw out using a .22 shell casing but man it is damn near impossible to get my meathooks up in there to turn it. Any thoughts or ideas???

Can somebody send me a email to etc_johnson@yahoo.com or maybe gimme a call? Send me a pm and I will give my number to talk about this. Thanks!!!!!

[Charlie D]

The vacuum hose lines look good, no cracks or leaks as far as I can tell. The tank vent hose is not kinked in any way. I am trying to get the A/F screw out using a .22 shell casing but man it is damn near impossible to get my meathooks up in there to turn it. Any thoughts or ideas???

Can somebody send me a email to etc_johnson@yahoo.com or maybe gimme a call? Send me a pm and I will give my number to talk about this. Thanks!!!!!

tank off seat off airbox off
ok now we are ready, you need a 17 mm wrench and at the choke lever there is a nut that holds to the bracket loosen and take knob out of bracket.
next up carb side back of carb there is a rubber boot with a hose clamp loosen it up now work the carb up and down and it will come out of the boot leave everything attached to the carb now you can tilt up the bottom and get to the screw.

you put everything back in reverse and make sure the tab on the carb fits back into the notch of the boot.

If you use a blue wire but connector it works better than the 22 shell, you just heat a bit shove over the screw let cool and now you have something you can get ahold of.

[Scar]

In the '04 1300c I just bought w/ vance/hines and a stock box with a k/n filter, it has a needle with 7 grooves and the "e" clip set in the 3rd groove from the end. I'm assuming that is a jet "kit" needle? What is the normal height for the "tit" inside the slider piston? I want to be sure the "tit" was cut per the previous instructions. No shims were found. If I were to add one shim, it goes between the "e" clip and the piston? Want to do this right the first time.

The needle is an aftermarket needle -- Yes, if you use a shim, then it goes under the "e" clip -- this would effectively raise the needle 1/2 notch height (0.02" shim).

The tit should be trimmed enough so that when the needle holder cap is in place there is needle movement from side to side.. If the needle is jammed against the tit (tit too long) it will not be possible to wiggle the needle.. it will also be difficult to screw/lock the needle cap holder into place.

[crewcf]

thank you for the info it has come in handy while doing some mod work on my 1300R
I have one small question about the fuel tank vent line there is a T fitting in it when I removed the tank it did not look like there was anything on the T just wondering if I missed somthing or is it just there so the overflow can drain out thanks
ps i have worked out a different exhaust mod and will post it in the proper place later

[burbek]

have you heard anything about the dg hard crome 2 into 1 side burners being to free breathing to be properly tuned to an other wise stock vtx 1300c. the guy i took my bike to got it to run really well on start up and acceleration. But you know the old story, deceleration is a bummer, it popps and back fires. Is he misinformed about this bike or is there some validity to what he says?

[Warlock4]

Got the bag of washers from Radio Shack, part # Scar posted. I need to know exactly what one to use. I have an '05 1300R Cobra Speedster slash downs, K&N in stock air box. Also, What is the PAIR system and should I remove it as I have read here and what does removing it actualy do? Thanks.

[jdr2dr]

Got the bag of washers from Radio Shack, part # Scar posted. I need to know exactly what one to use. I have an '05 1300R Cobra Speedster slash downs, K&N in stock air box. Also, What is the PAIR system and should I remove it as I have read here and what does removing it actualy do? Thanks.

I have 1 shim (should be about .022 thick) 2.5 turns out on the pilot screw(A/F screw) You might be ok just adjusting the A/F screw 2.5 turn out - you might not need a shim...

PAIR removal is on the site somewhere... all it does is STOP the popping (backfiring) - does nothng to improve performance -- just the tone and sound of your pipes... Stock pipes cover and hide the backfiring... After mkt. pipes are more free flowing and you hear the popping...

Jim

[Warlock4]

Thanks jdr2dr.

[Scar]

Got the bag of washers from Radio Shack, part # Scar posted. I need to know exactly what one to use. I have an '05 1300R Cobra Speedster slash downs, K&N in stock air box. Also, What is the PAIR system and should I remove it as I have read here and what does removing it actualy do? Thanks.

The #4 washers in the bag... they are the second from the smallest in diameter.

[Ken_r_mer]

Bought a 2004 1300c w/ V/H long shots, K/N filter in stock air box, 195 jet (stamped) with a needle that has the "e" clips set in the 4th groove from the end w/o and shim.

During a short hard acceleration while in idle I get a short puff of sooty exhaust, plugs are black, and it smells rich at idle). So I'm presuming I'm running rich.

With the bike came the honda "special" pilot screw tool. Should I tune it according to the Honda repair manual procedure, or should I turn in the pilot screw at 1/8 increments (45 drgrees) per the "scar" method?

P.S. Even with the special tool, its a bear to get at while the carb is on the bike. What was Honda thinking? Now if somebody can design a screw extension similar to the idle speed screw that can be attached to the pilot screw...I'll buy it.

[Scar]

Bought a 2004 1300c w/ V/H long shots, K/N filter in stock air box, 195 jet (stamped) with a needle that has the "e" clips set in the 4th groove from the end w/o and shim.

During a short hard acceleration while in idle I get a short puff of sooty exhaust, plugs are black, and it smells rich at idle). So I'm presuming I'm running rich.

With the bike came the honda "special" pilot screw tool. Should I tune it according to the Honda repair manual procedure, or should I turn in the pilot screw at 1/8 increments (45 drgrees) per the "scar" method?

P.S. Even with the special tool, its a bear to get at while the carb is on the bike. What was Honda thinking? Now if somebody can design a screw extension similar to the idle speed screw that can be attached to the pilot screw...I'll buy it.

Sooty plugs are commonly caused by the enricher (choke) if all else on the bike appears to be running properly. Clean or replace the plugs and do not use the choke for starting the engine -- Use the throttle control to maintain idle speed until the engine warms enough to idle on it's own -- The enricher (choke) is a known "issue" with this bike and most do not use it for these reasons.. once the plugs have been "sooted" they rarely clean themselves..

Hick makes an after market A/F screw that I believe can be operated with a socket extension.. ask about it on this forum on the 1300 page, someone will have the answer.

After cleaning or replacing the plugs, start the engine without using the enricher and keep the idle UP with the throttle control until the engine will idle on it's own.. Take the bike out for a run on the highway for at least 15 miles to achieve full operating temperature and then make your decisions as to whether or not the engine is "tuned" properly. If everything seems "good", then the sooty plugs have most likely been caused by something "out of whack" in the enricher circuit or by using the enricher.

[itrider]

Thanks to SCAR and BARTTODAY, I was able to successfully complete the SCAR carburetor adjustment method. I created a detailed PDF of my experience to help others through the process.

Here is the link:
http://www.itrider.net/downloads/CarburetorAdjustment_SCAR_Method.pdf

[Scar]

Thanks to SCAR and BARTTODAY, I was able to successfully complete the SCAR carburetor adjustment method. I created a detailed PDF of my experience to help others through the process.

Here is the link:
http://www.itrider.net/downloads/CarburetorAdjustment_SCAR_Method.pdf

Congrats on tuning your bike.

Attempting to help others if you haven't tuned several hundered bikes is kinda dangerous tho... there is a "guy" that has a forum elsewhere that does that here (leaving links and not having much real time experience) and it is usually just a "one time Johnny" shot... Charlie and Rich have tuned a few bikes and have a pretty good grip on it... but be careful or you will be biting off a "big chunk" and there will be lots of people asking about problems and some of them go way beyound "tuning".

Have a good summer... the weather out this way is great!!!

[itrider]

Thanks for the heads up SCAR. I did no more and no less than what was outlined by yourself and other experienced tuners.

Tuning and me = Not so good (that was why the thread and pdf defaulted to the pro's for advice)
Writing manuals and taking pics of processes = Much experience

Sorry if I upset anyone. I only wanted to help others where I struggled (the damn A/F screw removal :D)

[waitabit]

Am I missing something here? It looks to me like i have to remove the carb and open up the bottom to get to the main valve and A?F screw. 2004 1300c

[Charlie D]

Am I missing something here? It looks to me like i have to remove the carb and open up the bottom to get to the main valve and A?F screw. 2004 1300c

you don't have to remove but you do need to take out of the manifold boot then tilt up.
helps if you loosen and take choke knob out of its bracket.

[Scar]

you don't have to remove but you do need to take out of the manifold boot then tilt up.
helps if you loosen and take choke knob out of its bracket.

+++1 Or you can just loosen the bands on the rubber manifold and tilt up.. either way.. removal not required.

[waitabit]

Thanks Charlie D,
Im Charlie B up in Juneau AK. My first attempt at tuning after putting on new pipes. Was pretty intimidated by all the connections to the carb. I will tackle it again this week.

[jbblume]

Thanks to Scar, Barttoday, and Itrider! You guys laid out the mod very well. I got it done this weekend and it pulls great through every gear. One slip-up, I got a little shaky with the dremmel, anybody know how much a new pilot screw cost? :D When I get a new one, I'll use a hack saw blade like Scar said.

BTW...V&H Bigshots, stock airbox, 1 shim.

[Charlie D]

This one would be cheeper than a stocker. http://www.factorypro.com/Prod_Pages/prodh80.html

Thanks to Scar, Barttoday, and Itrider! You guys laid out the mod very well. I got it done this weekend and it pulls great through every gear. One slip-up, I got a little shaky with the dremmel, anybody know how much a new pilot screw cost? :D When I get a new one, I'll use a hack saw blade like Scar said.

BTW...V&H Bigshots, stock airbox, 1 shim.

[jbblume]

Charlie D,

Thanks for the heads up. It looks a heck of a lot easier than messin' with the stocker D.

[waitabit]

Things not so well here. I put in the new nedle with the clip in the proper place and raplaced the main jet and all was well for about 15 miles then the bike died. Restarted and went a half mile more and died. Restarted and went 400 feet. Pushed it into a friendly persons yard and will work on it this week. Possibly a hose came undone. Seems to be a fuel thing. Guess my first attempt at carburator work wasnt so very sucessful.

[waitabit]

Thanks to Charlie D about being able to work on the carb after freeing the choke knob. I sucessfully changed my pipes and adjusted the carb only to have my bike quite on the highway. It seemed I wasnt getting fuel and the battery seemed to go dead very quickly while trying to restart. Since this was the first bike work I had done I blaimed myself for doing something wrong. I hauled my tools to the site and rechecked the carb work and after having the bat checked, charged and installed, the bike started and ran great. I think I had a bad bat connection. Something so simple. Check the battery first..

[jlorange]

amazing what a bad connection can do. I rode my brothers Harley sportster on a visit. bike started and ran fine for the first half of the trip, after a pit stop though it wouldn't start, like the battery was dead. had to push start it, but it would start and rev a few times then die. broke out tools and checked all kinds of stuff, carbs, plugs, no luck, finally moved the battery and saw the cable was loose. he had taken the battery out to charge, just didn't get it tight when reinstalling.
+1 to checking the battery first.

[SLAMMER]

I have noticed there hasn't been any mention of the "e" clip position on the needle. What am I missing? Isn"t it important? Please help me understand before I tear into my carb.

Thanks in advance, slammer

[jdr2dr]

I have noticed there hasn't been any mention of the "e" clip position on the needle. What am I missing? Isn"t it important? Please help me understand before I tear into my carb.

Thanks in advance, slammer
if your carb is stock, w/o jet job then you have no "e" clip

Jim:choppersm

[SLAMMER]

Thanks, I had a jet kit as suggested when I did my pipes & hyper-charger. I am going to go over it again via scars' mod. because I've been running very rich.

thanks, slammer

[Scar]

Thanks, I had a jet kit as suggested when I did my pipes & hyper-charger. I am going to go over it again via scars' mod. because I've been running very rich.

thanks, slammer

Don't forget to trim the tit under the needle holder and check for free needle movement... you are lucky that you still have the stock parts to put in there.. some don't.

[SLAMMER]

Performed carb mod on saturday, bike runs great now! Thanks for the step by step it made things easy. Next up is pair removal.
Thanks to all,
slammer

[hamph]

or you can take that factory pro needle and make one of these.

[tbonevtx]

All that in for is great but I have dg american classics 200 jet Dyno Jet )and a k an N air filter. No problems all last year . No problems last month Today it idles great ran great for the first 1/2hr then acted like it ran out of gas!. Wont start . Finally get it started by fiddling with the choke have to ride wide open 2 nd gear or it stalls so i can get hom. And yes it has gas. 3 hours later I start it idels great do one hell of burnout in from of house get 1 mile stalls like runs out of gas plop pop chug chug plow wine . Hey I looked real good burnout to loaser ojn the side of the road. Get started finally open throtle in 2nd just to get home. Go in house open a beer and now vent!!!!Any ideas ?1300c

[Charlie D]

All that in for is great but I have dg american classics 200 jet Dyno Jet )and a k an N air filter. No problems all last year . No problems last month Today it idles great ran great for the first 1/2hr then acted like it ran out of gas!. Wont start . Finally get it started by fiddling with the choke have to ride wide open 2 nd gear or it stalls so i can get hom. And yes it has gas. 3 hours later I start it idels great do one hell of burnout in from of house get 1 mile stalls like runs out of gas plop pop chug chug plow wine . Hey I looked real good burnout to loaser ojn the side of the road. Get started finally open throtle in 2nd just to get home. Go in house open a beer and now vent!!!!Any ideas ?1300c

you might think about listing the year of your X in your info.

there is a recall on some for a bad fuel valve 06-07 models I think.
next up is you might have a broken wire on the ECM it is on top of the battery, or you could have loose battery cables or a pinched fuel vent line.

next time open the gas cap and then try again that would release the vac on the tank if it is the vent line.

Bike will not run right with loose battery cables and they will vibrate loose over time use a wrench on them.

[tbonevtx]

Its a 2005 so the recall doesnt count checked cables Need to pull the tank and check lines . I would say it could be the ecm but i dont know. I did open the tank fill could tell if that helped. I was bit mor interested not in getting run over was a two lane road one each way on the side in a curve just a great spot to get stuck!

[tbonevtx]

Checked batter tight . Checked ecm wires look good. all vent lines look good. The question I have is the vent from the tank goes down to the bottom of the frame is it suppose to go somewhere in particual? Also there is a t in that line under the front of the seat is somehing suppose to be on it . Or does it just vent under the seat ? Also pulled plugs front seem white but back ones seem Brown?

[Charlie D]

plug color is normal both cylinders don't always run the same.

That line has the Tee so if the tank is overfilled it won't syphon it dry, lets some air in to break it up.

[Ken_r_mer]

Came across vtx1300tips.com. It has detailed list of performing different mods. One section has a chart of over 20 combinations of air filter / exhaust / carb jet size / and "e" clip settings. A few even had dyno test results. Find your combination and use as a guide to zero in on carb adjustments.