Carb. and Exhaust backfire - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 16 (permalink) Old 03-22-2006, 09:45 PM Thread Starter
 
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Exclamation Carb. and Exhaust backfire

At low rpms (3000 and below) I can hear my carb backfire with my exhaust. Its driving me nuts.. what could be going on. Oh, Its the front cylinder thats doing that. It has good power at crusing speed but, it has slow deacceleration. If anyone has a idea what to do let me know. 1999 vulcan 750 with 15,000 miles...James
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post #2 of 16 (permalink) Old 03-22-2006, 11:11 PM
 
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Sounds like you may have an exhaust leak. Check the clamps and exhaust gasket. Have you done any work on it recently, or did it just start backfiring?
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post #3 of 16 (permalink) Old 03-24-2006, 08:47 PM Thread Starter
 
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It just started backfiring...I noticed a downgrade of performance for a while so i had started putting fuel cleaners in every fillup. Then oneday i noticed the carbs popping and the exhaust as well.
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post #4 of 16 (permalink) Old 03-30-2006, 10:37 AM
 
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Quote:
Originally Posted by JamesMcD
It just started backfiring...I noticed a downgrade of performance for a while so i had started putting fuel cleaners in every fillup. Then oneday i noticed the carbs popping and the exhaust as well.
There is a little vaccuum line on the right carb, Mine was backfiring and i took it off and put a little cap on it. that made a big difference. now it only back fires when i am coasting down a hill st high speeds. (40mph and up)
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post #5 of 16 (permalink) Old 03-30-2006, 10:38 AM
 
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It could also be an exaust leak like the guy said above.
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post #6 of 16 (permalink) Old 04-09-2006, 11:35 PM
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putting cleaner in it every fill up is too much, it could be doing an odd burn cycle on to much cleaner, that will also wear the exaust and give you a leak.
try waiting for a mo. then put half a can of seafoam and run it at speeds of 40mph up to 80 fast, that will clean out the carbs, or just do a maintance on the carbs. u can also check the air fuel mixure... there could be alot involved and there could be one easy thing.
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post #7 of 16 (permalink) Old 07-19-2006, 03:30 PM
 
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I got the krackles too. On every deaccelleration like forth of July. I'm trying to pretend it's intentional but no one can see my convincing look through my helmet. I just try to speed home and go in the bat cave. I read on line here that putting marbles in the vent tubes might help. I can't find the artical. Anyone out there tried it with success?
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post #8 of 16 (permalink) Old 07-20-2006, 05:18 AM
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Quote:
Originally Posted by lindan310
I read on line here that putting marbles in the vent tubes might help. I can't find the artical.
I haven't done it, but HERE'S the thread from the Vulcan Verses that might help ya.


AKA: Tim & 'The Adventure Cycle' VROC #24567, NEVROC, SteelCity VROC


"When life throws you curves,
Aim for the apex."

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post #9 of 16 (permalink) Old 07-27-2006, 04:57 PM
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The easiest thing is to go through the exhaust system and check for loose nuts on both the exhaust pipe and the manifold on the cylinders. If these are loose and leaking air into the system, you will get the pops that you describe and no amount of cleaner or Sea Foam will fix it. It takes about 10 minutes of time to check. Why futz with esoteric solutions if it's that easy?
The vacuum line on the right carb goes to the evaporative fuel recycling system. It creates a low pressure that allows gas fumes to be sent to a charcoal canister rather than venting into the air. If this is causing the popping, there is a problem somewhere in the system.

Jim W
93 VN 750 "Ursula"
Moved R/R 08Sep06
R/R rewire 17Feb07
New R/R, Installed 14Jun08
New Stator installed 10 Jun08
Maintenance Free Battery 12Jan08
21480 Miles
VROC #8542
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post #10 of 16 (permalink) Old 08-01-2006, 11:46 PM
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Installed Marbles

I posted this on another forum (the wrong one) so I will repost here;

I marbled my bike today. Made a HUGE difference! I only get a slight pop from the rear cyl. when suddenly coming off the gas. I may have to consider the carb screw adjustment next. One thing I don't want to do is sacrafice reliability for silence. Any help or cautions anyone can give about carb adjustment? I read other posts here about how to do it, but one question I have is; are the lead-covered screws actually on the side of the carbs instead of the bottom as I have read? Looks like the same thing, but much easier to get to. The carbs are Kleihns.

Also- is there a written procedure for relocation of the R/R? I still think I am cooking it with my goat belly.

Thanks.

Ben-
SW Ohio

'02 VN750
Pipes drilled
Spline lubed
R/R relocated
AGM batteried
Iridium equipped
LED tail lighted
8000-ish miled
Soon to be MCCTed

Lovin Life.
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