bad miss and backfire at 5000rpm. And a flat spot - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 5 (permalink) Old 04-19-2009, 11:19 AM Thread Starter
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bad miss and backfire at 5000rpm. And a flat spot

mises at 5000rpm ish
Ive got the electrics sorted but now i cant get the bike to run right.
Pulls away ok but at 4-5000 rpm the bike will mis and pop and bang. Or if i hold the throttle at this
position with the bike on stand will do the same...
The front cylinder is lean and the rear looks ok, maybe tiny bit rich.
I have pod filters on and 142 main jet, goats belly removed, and aftermarket exhausts.
good voltage at the battery electrics chek out ok.
not sure if the coi would cause this
The bike ran ok 1 day then gave up the next...
Do my carbs need cleaned again!
Ive just put in new plugs and new clips on the rubber moubts that go from carb to head. And all is tight.
It gets frustrating when u solve one problem then find another...
Any suggestions appreciated...

Its not sticking valves are anything bad, i can handle taking carbs of and cleaning.
ps No Sea Foam in the UK so ive got to do the manual side and hands on...
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post #2 of 5 (permalink) Old 04-19-2009, 11:40 AM
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Did you sync the carbs after removing & cleaning?
If not, there's plenty of write-ups on how to make a manometer and the process of syncing then.

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post #3 of 5 (permalink) Old 04-19-2009, 12:02 PM
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Did you clean the fuel tank??? If not you may need to clean the carbs and tank.

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post #4 of 5 (permalink) Old 04-19-2009, 01:11 PM Thread Starter
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i havnt synced the carbs yet, mate has the colour tune and sync meter so organising a tune up. will the mixture settings cause the problems im experiencing?
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post #5 of 5 (permalink) Old 05-05-2009, 04:47 PM
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Let us know when you get the answer. I'm getting the same thing - misses from 4000-5500 rpm, then I get a sweet spot from 6000 to 7000 rpm where it flattens out. Popping on deceleration.

The bike has been sitting 3 years. Carb was rebuilt 8000 km prior to that. I've run fuel line cleaner (not Seafoam) through, no results.
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