Yfz starting problem

[racer113]

I just repalced the piston and jug

and can not get the motor to start

I have spark

I have fuel

Cams are lined up (flywheel lined up)

I have tried rotating the motor 1 revolution and re aligning the cams to make sure I am on TDC compression

any one have a simmilar problem

[zzsa02]

check your valve clearances. I was just fighting the same thing and all of valves were off.