Motorcycle Repair: Old Stroker, intake leak, jets

Question
I'm tring to fire up a 1974 Sporty that has a S&S stroker kit, I've tore apart and cleaned and the old L series carb that is on the bike installed new points, plugs. I got it to fire up, but there is a lot of backfiring thru the carb and I can't seem to idle the bike down it keeps running around 3000 rpm I've got the idle screw turned all the way down and I've advanced and retarded the timing, cant seem to make her purr,  any suggestions would be appreciated

Answer
The screw to idle the bike turns outward to idle it down. Also, your cable might be to tight and that is keeping the idle up. Coughing through the carb is a sign that your valves might be to tight or you have an intake leak. Also, on of your jets might be slightly plugged with dirt
Good luck and happy riding
Mike