1985 LT230 backfiring

[LT230quadsport]

my son and I are restoring an 1985 LT230.rebiult entire carb new everything in it Timing is set dead nuts after reboring cylinder and replacing piston and rings. Engine is hard starting and when does start engine will only run with choke on idle revs up pops through carb and goes down. when you crack throttle enginge backfires through exhaust and carb. any Ideas would be great thanks

[DirtDemon]

When you say the timing is set, are you talking about the valve timing or the ignition timing? If you have a backfire going through the carb one of them is most likely off. A broken flywheel key will throw off spark timing and the cam timing will look like it is set, but since the timing mark on the flywheel is offset from where it should be in relation to the crankshaft position, it too would be off. You could have a stretched timing chain or a bad tensioner. I would double check all timing components, make sure everything is properly set and the flywheel shear key is in tact. Good luck.

[lawny]

I agree with DD, sounds like a timing issue.