Motorcycle Repair: pipes backfiring, intermediate jet, sure what kind

Question
QUESTION: 83' sposter 1000cc. I have a new carburetor and have been having problems with serious back firing from the pipes and the carb. Flames and all. What might it be. I am not sure if it is the plugs or not. I am not sure what kind of plugs it need because i am not positive the existing plugs are right. No mechanics around. any info would be helpful.
ANSWER: What carb are you running and was the carb jetted after it was installed? Also, pull the plugs and let me know what color theya re
Mike

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

QUESTION: It is an S&S super it was jetted. And the plugs are a little black but don't seem to be fouled. The rear cylynder is burning rich and want really start it just backfires.

Answer
First, do a OHMs test ont he coil and plug wires to make sure they are good. Check your plugs to make sure they are gapped at .040. Start the bike and once it warms up spray a little carb cleaner around the intake manifold. If the RPMs go up then you have a intake leak. If all the above check out then I would go one jet smaller with the intermediate jet
Good luck and happy riding
Mike