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Medium RPM Sputtering.

3K views 17 replies 9 participants last post by  AZVTX'er 
#1 · (Edited)
:( I need help.
Symptoms:
Low RPMs – The bike doesn’t seem to have the proper ‘get-up-and-go’
Mid RPMs – When cruising at about 40mph and 50mph, the bike seems to stutter and hesitate. same between 68mph and 72mph
High RPMs – The bike seems to handle well at this range. When I open the throttle, the bike really picks up and accelerates nicely in the high range.
Decel Popping – There is considerable amount of decel popping when going from high RPMs down

Running:
stock air box
K&N air filter
Clayton Mod (6 holes only in first backplate)
pair valve blocked off. (original pair covers bolted closed and rest removed)
Scar mod first 1 shim under needle, then 2 shims, both tried with a/f or pilot screw turned out 2 1/2 and 3 turns.

couldn't take it anymore (lack of space, time and light to work on her) so I took her to the dealers maintenance shop.

3 days now and they are still struggling. now they say they think its an electrical issue.

Kevin: http://www.vtxoa.com/forums/viewtopic.php?t=207975 has similar problem. (sorry Kevin, kinda used your symptoms description)
 
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#2 ·
Has your bike done this since you did the Scar mod or start doing it later on? Sounds like it is rich. Also, make sure the choke is pushed all the way in. If it is not running rich you have a pinched vent line to the tank or a vacuum line leaking.
 
#4 ·
Went to dealer today and the bike was on the dyno. Tech reckoned it's not a carb issueas he tried different carb jetting. showed me that bike sputters / power loss at 62 mph. He is waiting for some parts to do fault finding cause he checked all electronics as stated in workshop manual. Now it's a matter of swap an try (and pray i guess).... but what could it be. Engine stop switch / igntion coils / ignition pulse generator /ICM. still baffles me, below 62 mph and above 72 mph she runs fine. (the dealer said he checked vacuum lines / battery / CDI. I even pulled the tank vent line while the bike was on dyno doing 62mph and no diff.) Waiting for them to try and find the fault is frustrating...... :-<
 
#8 ·
I had that problem with another honda I had what I did was bought a big air kit and rejetted and that fixed it right up. The other bike wasnt a vtx but that fixed my problem.
 
#9 ·
Dealer called, told me that bike was ready for collection. "Apparently" it was the Stator pickup (Igntion Pulse meter).
So got to the shop, paid, left, drove around the block and it did the same. Went back and wel....long story short - two hours later - after I had to help them find the problem, which I already paid for, we found one of the wires on the ECI units harness finally broke. It was broken off inside the plastic sleeving and when we checked, rechecked and then some more the plastic sleeving finally broke and thus revealing the problem. hmmm. freaken stealers.... And by the way - the pickup was not changed like he stated.... cause we only did that once I was there.(original sealant on cover - they only have black and honda uses the grey one) :mad: :mad: .
Thanx to everyones advice. Thought I would just share the problem, maybe it will help someone, someday....:beer:
 
#14 ·
I've been having the same kind of problems with my 07 VTX 1300 and the other night (after reading some of the posts on this site) I checked out my ICM and guess what....yep, one of the wires at the back of the connector was broken (green wire with grey trace spots). This wire is at the top left pin position on the ICM connector as you look into the face of the connector without the ICM module in place. Not sure what function this wire performs since the blasted Honda service book schematic does not match the wiring harness colors on the bike. If any of you guys know the function per pinout on the ICM for an 07 VTX 1300C and want to share...that would be great.
Made the reapir and will check tonight on a long ride to see if this fix takes care of my problem.
Keep the info flowing.....the more we share...the smarter we all get.
 
#15 ·
Recently a C.R.A.P. Member was having trouble keeping his running and found some corrosion in the main ICM connector. There was also some corrosion found in the 2 prong connector which he also cleaned and then used some CaiLube L260Np thixotropic paste (grease for electrical contacts) and all has been well for several weeks now. ;)

Biddy
 
#17 ·
I've read some excellent responses back to this posting over the past few days and one of them regarding the breakage of the wires on the back of the ICM I felt should be shared.
The fit and mounting of the ICM on top of the battery is marginal at best and will allow the module to bounce around and vibrate in sync with the pulses of the engine and road conditions and in so doing fatique the wires on the back of the connector. A good solution to this (what I've done) is to put a thin layer of soft foam under the module to isolate it from the vibration and then further secure it to the battery top cap by using a velcro mounted strap between the existing plastic ears that are there to secure the ICM.
 
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