Motorcycle Repair: FXSTC 1991 w/ superE Carb - backfiring, rear cylinder, fxstc

Question
Bike was running well, but at very low idle (stalled at stops alot)  
then mechanic adjusted idle up.  The next day, after putting gas
in it and driving about 50 miles, parking it for 3 to 4 hours and
then starting it up again, it began to backfire and was hard to
keep running, and has been since then.  Ran another tank of gas
thought it.  Seems like rear cylinder not firing.  Changed plugs,
cleaned carb, tried to adjust idle-air/fuel mix.  Still acting the
same.  

Answer
First thing I would do is test the coil and plug wires to make sure they are good. Then test the ignition. Check the intake manifolds for leaks. If all this is good then check the carb to see if you hae a plugged jet.
Good luck and happy riding
Mike