Ok so I just bought a 2003 400ex that has just been rejetted and had a 11:1 dometop piston standard bore. The boy that I bought it from said after he did this it would run for a short time and then kick itself out of time, however it will not run at all at this time. I checked the timing and it is in time. When I turn the motor over it will wind for a second then hit and wind some more and hit again. Could anyone tell me why it will not crank haha. I currently have the head removed and now would be the perfect time to fix it.