just had local dealer rebulid tranny,bore cylider 80 over and install a j&e 12:1 pistion now it sounds like the valves are hitting the pistion. i need help what do you think is the problem. it a 2001 raptor

 

If they are hitting the pistons it would only happen for a little while about a second or so before everthing that you just but into your motor would be scrape. This will usally bend valves first and than start working on the piston as the head of the valve breaks off and starts to beat the inside of you motor to death. I hope your not still starting the motor.

Return to who ever put it toghter and have them evaluate it.

Smitty

 

it sounds like the valves are too losse but i check them last night and thier in set to what the book says. has any one had a problem with the pistion hitting the valves.

 

this sounds like it could be multiple problems.chances are they valves aren't hitting the piston.if the entire motor was disassembled then it could be a variety of things,timing could be a little off and you might be getting bad detination,you might be running to low of octane fuel and getting bad detination.or the valves may need to be readjusted.or the bore job on your cylinder could very well be out of tolerance and you're getting severe piston slap.and if thats the case you're going to break a piston skirt or break a cylinder skirt and then plan on paying for it all over again.
hopping up a motor can be very costly when done right the first time. good luck i hope you get it figured out with little problem.

 

If your valve was hitting the piston it would've bent at the least & your compression would be noticably lower to the point of being much harder to start.

like others have said your problem probably lies elsewhere as valves won't take much of a beating before failure.

If you put in a higher compression piston you must use higher octane fuel or you will have detonation that would sound like the valves hitting.

 

im run 92 gas. it really sounds bad it makes a tapping sound we adjusted the valves tight and then loose and the noise is the same im going to try so new gas next and see if it helps. the bike has been ran for a about 30 mins so i think if the valves were hitting the pistion they would have broke by now.

 

think you're right if it's been ran that long then you would have seious valvetrain damage by now if the valves were hitting.by the way who did your motor work?

 

Sounds like detonation.