Motorcycle Repair: My 92 600 katana backfires..., plug wires, harleys

Question
My '92 600 katana backfires badly, especially when it's in gear, It's unrideable. I put in new plugs (the old ones where real black and dry)and the coils are only a year old. Sounds like carbs, right? Would cleaning them with the spray stuff be enough or is this something worse.

Answer
I usually only answer questions on harleys, but I might be able to help. If you bike had been running fine and tehn you started having hte problem, then its not the carbs. You either have a bad coil, plug wires or ignition.
Good luck and happy riding
Mike