Ive got an 07 BF 750 that idles fine and runs fine under light loads but when you try to rev it up or apply full throttle it sputters and backfires. I recently had the carbs cleaned and installed a LRD torc series exhaust. Will installing a jet kit fix this issue or is it something else? I also get oil from the crankcase from backpressure into a catchcan i had installed. Any help is appreciated thanks.