I have a 2004 bear tracker 250 yfm I just changed the cam shaft timing chain, guides and tensioner timed up by the book went two start it 3 times motor backfired and pushed the rubber sleeve that connects the carb to the intake off of the intake. I loosened the clamp and put it back on and all 3 times did the same thing ran like a top before doing this just could here the chain slapping and the cam was worn all new part timed up right any help would be greatly appreciated

 

Sounds like timing wrong to me. Check that the piston is at TDC when the flywheel mark says it is. You may have got the flywheel on wrong.

 

the only way that could happen is the keyway slipped out when I put it on but it dose stay true to the mark and stay in time to the mark but it is something to look at it just dose not sound right when turning over it dose sound out of time almost like the timing chain is off but it not maybe the key way is jammed up behind the fly wheel will check it out thanks

 

the fly wheel is 100% on there right it always stays true to the mark and always go to tdc with the mark I even set the valves witch were way out still got the same problem nothing but Backfire I'm so stumped on this

 

Double check that valve timing, are you sure it was the TDC, not the ignition, mark you set it to?

 

I have double and triple checked the timing and valve setting I know the difference between a t and a f and it always stays on the t on fly wheel and always comes to TDC and the valve setting has also stayed true I am so stumped at this everything by the book and it still wont start just backfires through the carb or exhaust: mad: