I just picked up a 300ex and the cam housing cover bolts were stripped and leaking oil. So I pulled the head to put some timeserts in and saw the ex. valves are hitting the piston very lightly.
It runs pretty good. The only thing I know someone did the top end and it has a Wiseco piston in it 20 over with 11:1 compression. Could the timing be one tooth off ?
Thanks,
Tom

 

That would be my guess.

 

yea the timing could be off a bit or it might not be off now but i bet somebody who had it before could have messed the timing up and put it back together and heard a noise then found out they didnt have it in time then they figured it out.

 

The marks are fresh no carbon on them. I did not check the timing before I took it apart.
I am used to two strokes, these will run pretty good one tooth off ?
Thanks,
Tom