ATV timing question?

[Fatback_pimp12]

i have lined up the cam marks when the engine is at the TDC (the mark "T" on the flywheel) spot, and i still get fire out the exhaust. it is a gy6 motor in a Eton YXL yukon 150.

what should i do to stop the misfiring? it is a big bore kit installed. just new cylinder and piston. original head.

[garyra8668]

turn the cam 1/2 turn and try it. some marks can be mistaken top for bottom.