Motorcycle Repair: 91sporty, air fuel mixture, plug wires

Question
QUESTION: S&S super E carb with drags.set the carb 1 1/2 turns on air fuel mixture,2 turns on pump screw,and 1/2 turn on idle from contact with the screw engagement.runs good until around 68-75 mph then breaks up once in awhile.also at 60 when you gas on it.any info would be appreciated.dont know what size jets are in carb.

ANSWER: Pull your spark plugs and let me know what color they are
Good luck and happy riding
Mike

---------- FOLLOW-UP ----------

QUESTION: plugs are black running way too rich.also not running baffles.thanks.

Answer
If your bike has been running fine before this happened then I would start by doing a OHMs test on the coil and plug wires. If you have a weak coil you will foul plugs.
If that is not the problem then you probably need to rejett. If you go to the S&S web site you will find the tech pages and in there you will find how to jet your carb.
Good luck and happy riding
Mike