intermitten popping and backfiring - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 4 (permalink) Old 02-16-2012, 10:53 AM Thread Starter
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intermitten popping and backfiring

does not do it all the time. I shut it off and the next time I go to drive it, it starts popping and backfiring and loss of power..changed plugs and is still doing it.any suggestions on what to look for??
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post #2 of 4 (permalink) Old 02-16-2012, 11:01 AM
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Originally Posted by Deb-V View Post
does not do it all the time. I shut it off and the next time I go to drive it, it starts popping and backfiring and loss of power..changed plugs and is still doing it.any suggestions on what to look for??
Tons of threads on this subject. Search "popping" in the 'Custom Search' engine above. Probably mixture adjustment or loose exhaust header gaskets.

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post #3 of 4 (permalink) Old 02-16-2012, 12:50 PM
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it could be a lot of things causing it, or it could be a combination of things contributing to it.
I recently battled the same scenario, and am not convinced it is resolved yet since I had not been able to get out and ride lately to test it.

air leaks in carb boots or exhaust can cause it as well as improper carb setting/sync/ fuel to air mix...etc

I found several issues that contributed to mine popping even after I coastered and removed the air injection system. To name a few:

lean carb setting
leaky exhaust header (missing crush gasket)
carbs out of sync
fouled plugs
and lastly I found that the lean condition was being caused by very thinly oiled filters.

I re-oiled my air filters and it was just enough to enrichen the air/fuel mix at idle......who'd a thunk it

do your research....good luck
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post #4 of 4 (permalink) Old 02-16-2012, 09:41 PM
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As was said, it can be more than one thing. Definitely remove the complete air injection system, and if it is a CA model, the complete evap system. The air injection injects air into the exhaust, causing it to run hot, and can cause popping and backfiring. The evap system can cause it to run either too lean or too rich. Next, if they are still there, remove the plugs covering the pilot screws on the carbs, turn the screws in until the seat lightly, then back them out 2 1/2 turns. That is a good starting point, you may need a little more or a little less. Make sure the gas tank is properly vented.

If none of these things help, then there is most likely something wrong inside the carburetors. But I would try all the other stuff first, as it needs to be done regardless if there is another problem.

If you have altered the intake or exhaust, all bets are off. The Vulcan has a very carefully engineered intake and exhaust system, and if you modify it, it can create all kinds of issues. The intake and exhaust systems determine how the air/fuel mixture flows through the engine at all engine speeds, and even a minor change can upset everything.

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2006 Sportster 1200 Low
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