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02 660 backfiring

1125 Views 1 Reply 2 Participants Last post by  dezz
I hope somebody can solve this problem. Started my machine a few days ago and whenever i give it any throttle it backfires through the carb HARD. Experience tells me a lean issue. Disassembled and cleaned the carb, checked the rubber carb mount for cracks, reassembled, no difference. Starts and idles beautiful. Raised the float slightly, no difference. Theres plenty of fuel in bowl. Replaced spark plug, no water in hole where it screws in. Valve lash is perfect. Took carb from another machine and Put it in, no difference. I'm out of ideas.
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Are you 100% sure the valve clearances are good?

Carb adapter boot torn?

Can you try another CDI from another bike?

Check timing. See if timing marks still line up. If so, pull flywheel and inspect woodruff key for shearing. This will cause the timing marks to line up but it's still out of time on the crank.
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