crf engine work

[joeb23]

I have a 2002 crf engine that I cant get to run. I bought it from a guy who said it ran fine, but it didnt. Opened it up found the valves were hitting the piston replaced one valve and installed the athena 490 kit. I put it back together and it back fired several times but wouldnt start. Im running it straight off the carburetor no airbox. I have had it with working on this engine and Im ready to send it off to have someone else work on it. If anyone knows someone I could send the engine to and has experience with the crf's it would be greatly appreaciated.
Thanks, Joe

[Sparky_20]

if the valves were hitting the piston then either it was over revved or the cam timing is off. Did you double check that the came timing is on? Did you lap the new valve into the seat? Check the compression.

If all that turns out good then check for fuel and spark

[Glamis400ex]

check the decomp lever

[joeb23]

Yes the timing was off one tooth and made a world of difference. We lapped the valve with valve grinding compound and everything. The timing is good now but my dad thinks that the timing in the cases might be wrong? Im not sure if thats even possible? I dunno.

[Sparky_20]

im pretty sure that the timing in the cases doesnt matter, unless your talking about a balancer shaft which wouldnt be off if the cam timing was off. I would check for fuel and spark then compression and leakdown