Has spark, fuel,compression set at 50psi throttle closed, 60psi open. good battery. checked all timing marks, flywheel, right side crank gear mark and cam all perfect, valves are set at .006 and .011. It has a Hot Cams stage 2, open airbox and rejet. it started out as it would not restart hot so i put the pilot jet back to stock and it restarted better but after the customer took it duning it got worse to the point of it needing a starter clutch. Customer didnt tell me it wouldnt run when he brought it in for starter clutch.Engine is spinning over better than ever, but it wont pop. I noticed the exhaust header was getting hot after cranking the starter for less than 10 seconds.(as in hot to touch but not burn) i checked the timing with a light and it was firing a bit advanced before the f mark. (about half the distance between the f and t) just the distance not where its firing..prob @ 6 degrees early. It has a new cam chain and it has no slack in it so the cam is as advanced as it ever will be.I have replaced the stator and cdi and nothing has changed. i have backed off the decompressor until it wouldnt push over the top. tps in spec,throttle and carb switches good. also i opened up the plug gap on another plug to @1/4" and it fired easily. I thought about the cam possibly spinning out of time due to a poss violent kickback during starting but i put the old cam up to it and it looked the same. I am missing something. help would be appreciated.