I've been searching for answers and it seems like I have covered everything, so maybe you guys can help me out. Here goes. Bike: '05 CRF 450R Bike ran fine last year but was very high on hours (no hour meter, and I bought it new). I decided to rebuild the motor. New crank, all new bearings and seals, timing chain, tensioner, guide, JE 13.5:1 piston kit, and new '08 big bore thumpers head with stainless valves. Still has stock exhaust and cam. Bike is all together and does not kickstart when cold. I can bump start it easily (have put 2.5hrs on it after starting it this way). It runs good, has lots of power, and restarts when its warm. Yesterday I laid it over in a corner and it was a bear to start. Kicked many times and it would fire but not start. Had to bump start it again. Here is what I have checked out: Intake valve clearance: .005" Exhaust valve clearance: .009" I put the .009 in the exhaust valve, and then the .014 in the decompressor and set it. I have checked and rechecked the timing according to the flywheel marks. I even tried it a tooth off and it wouldn't start that way either. I have the second hash mark on the flywheel lined up and the cam mark and pointer lined up. I have also cleaned the carb. out thoroughly. 168 main 72 starting jet 42 pilot jet and 1 1/4 turn out on the bottom carb. adjustment screw. What do you think? What am I missing?