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Discussion Starter #1
What affects what in the carb of the 1300 VTX

There are 3 things to deal with and each affects the other in some small way.

1, main jet
2, pilot jet
3, needle position

Lets start with the main as it is the easy one
selecting a proper main jet is sometimes hard for some so some tips to doing it properly.
First thing you need to do is give an educated guess or just toss a 215 in for trial,
now you want the bike up to temp about 8-10 mile ride then get the rpm up around 3500
you don't have a tach. so lets say 45 in second gear roll on the throttle and pay attention
to how the rpm reacts it should be a good steady strong pull right up to the rev limiter
if it is sluggish at the start and gets better as the rpm builds you have 1 size to large in
and if it stops building good power before the limiter you may be 1 size to small.

Next step is the needle position if you are running an aftermarket needle it has grooves and
your clip should start at the 3rd position from the blunt end, if running the stock needle leave
it as it is NO SHIMS yet.
Now you take it out for the 8-10 mile warm up and now you want to be in 4th gear doing around 50
roll on the throttle hard if it boggs down then takes off and builds good rpm your needle is to high
if it hesitates (stutters) your needle is to low.
If to low which will be 90% of the time add 1 shim this should be around .025 thickness give or take
a little, now go and do the same test, repeat till you have what you like, with after market needle
you would remove the shim and move the clip (shim is about half a clip position).

Now on to the pilot jet every VTX from the factory is very lean on the bottom end so you should
start with the 58 if running a heavy breather you should have a 60.
start point for the setting of the idle drop is

55 jet should be around 2 1/2 (stock box)
58 jet should be around 2 (spyker mod or decap with K&N)
60 jet should be around 1 3/4 (Hyper, BAK, Ashford, Doug's,.......) all heavy breathers

now you get the bike up to full temp again then set the idle up to around 1000 and it is going to sound
fast, you will now blip the throttle a little and it should return to the 1000 without hanging
or dropping from your 1000 initial setting, if it drops below you are rich if it hangs up you are lean

Ok now you have some base points to work from

Review
Main jet is from 3500 rpm up to red line (Speed limiter)
Needle position is from 2500 to 3500 rpm
Pilot jet handles from 900 to 2500

Some of the main problems we face are lean surging at cruise this is due to the pilot jet being to small
and at most cruise speeds 55-65 we are in the 2500 rpm range and what I see 90% of the time is raise the needle
or open the A/F neither will work 100% of the time and we end up chasing our tails.
When you open the A/F up above what it should be for the idle drop is run rich at idle then you hit around 1500
rpm and you are once again in the lean stage so what do you do well we raise the needle to compensate and this
once again puts us back to a rich state till we get up to around 3000 rpm.
So in a sense we just try to cover up and say all is right.

If you want the best low end torque for low speed you need the correct pilot jet
If you want the cruise speed surging gone again the pilot jet
If you want the best acceleration at cruise for passing you need the needle position correct
And last if you like high speed power to the top you need the best main jet.

I have found settings I love to run like full on power right to the top starting at 30 mph in 5th gear but I hated the
30-32 mpg so I compromise and get 38-40 and still have great power.
 

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dizzy member
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dude..... you rock... i know some of this is coverd in the factory pro tunning but this is worded better.... thanks for the write up...
:mosh::mosh::mosh:
 

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Excellent article. You temp me to tinker more with my carb, but I love my carb as it is currently tuned with 1 shim/Ashford's breather/Hard Kore baffles. It pulls well at all throttle levels - no flat spots.
 

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Awesome!! Good article with a lot of good information!!
 

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Dragon Slayer
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Besides the Sticky, put a link to it in the "Answers to Common Questions"

You rock Charlie :cheers: :patriot:
Definitely needs to be in answers to common questions, Charlie has just explained to where it's so easy, a cave man can do it.....
 

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Yes a sticky!!! I am getting ready to redo mine and this has helped so much! Thank you!!
 

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thats awesome charlie! Where can i get the #60 Pilot? can you post the link up?
 

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a big trunk for my junk
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+1000 for sticky
This brief post nailed down whats wrong with my low speed throttle response.. can't wait to adjust my carb.
Thanks CharlieD
 

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Thanks CharlieD for putting this together...

I just want to add to all this...
I've been chasing my tail for a while and it always seemed that I was running rich with poor mileage (33-36) no matter what i did. Turned out to be the choke (enricher) was sticking open as Charlie has mentioned before. Slapped a stronger spring in there and now I'm up to 42 highway and 46 cruising around 45 mph steady. Make sure you check the choke so its not hanging up it drove me nuts for good long time.
 

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Discussion Starter #18
thats awesome charlie! Where can i get the #60 Pilot? can you post the link up?
I have a local (all brands) bike shop that found 2 of the 60 pilots in the USA so I got one of them I think it came out of Texas, (it cost me a whopping $8.50 delivered) dealer charged me $13 for the 58.

You may be able to order one direct from Factory-Pro.
 

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Thanks CharlieD for putting this together...

I just want to add to all this...
I've been chasing my tail for a while and it always seemed that I was running rich with poor mileage (33-36) no matter what i did. Turned out to be the choke (enricher) was sticking open as Charlie has mentioned before. Slapped a stronger spring in there and now I'm up to 42 highway and 46 cruising around 45 mph steady. Make sure you check the choke so its not hanging up it drove me nuts for good long time.
Where exactly is the spring located?
 

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Discussion Starter #20
Where exactly is the spring located?
the choke is cable operated and inside the carb there is a plunger with a spring holding it down when the knob is pushed in, I noticed that mine with vibration would open or bounce up so I removed the cable and put a heavy spring in.
 
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