I bought my son a used, 2008 Dragon 800. It ran good the first 2 rides. The 3rd ride, he was riding, and he said he heard a pop, and then it ran funny. It seemed to idle high, and sound different, and the power was less. we headed back, but after a few miles, it wouldn't hardly run. It seems to be firing on both cylinders, but it sounds like its only running on 1. I don't know much about these sleds, so any help would be appreciated.