I have a 1990 low rider ran fine then it back fired and quit. last week I took the carb off replaced the intake gaskets and the plastic elbow on the cv carb there was cracks in both of them. today I take off runs good then it does the same thing,I get it home let it cool and it starts up i hit the igniton sensor whit a hair drier and it quits. i replace the ignition sensor with a H.D.stock sensor now I can't get it timed. HELP!