OK here's the deal, I have an 03 YZ450 that is about to drive me nuts. I put a new timing chain on it the other day, put it together, kicked it 3 times fired up and ran fine. Took it to the track today kicked my butt off and it finally started and ran great. Shut it off, took a break, 3 of took turns kicking and it wouldn't start. Went back about 45 minutes later, started 1st kick ran great. Shut it off, to take a braek. Hasn't started since. I 'am tired and my leg is sore from kicking. PLEASE help.