first off just wanna say hey new to the forum i ride a minted out 86250r, but my brother rides a 99 400ex. all the threads on the head were messed up so we just got a different head that has new seats, valve, and seals done by a shop. also i am putting in a stage 2 hot cam. well i was trying to time it and when ever i have it set i let the tensor tighten up and it pulls it back to far so i moved it forward one tooth and tried again and its still off. i was thinking the cam chain is stretched what do u guys think. i can take pics tom. and i was reading about the crf450 chain what all do i have to do to run that..... thnk u