well i went riding with my 2001 660r today with my friend. first time i had a chance to really ride it since i got my maxxis razrs (which by the way kick A**). anyways we were riding for about and hour and a half, two hours. mud and hills havin' a blast when we were messin around thrown mud. I was then going to head out to hit the hills when the fourwheeler stalled. so i started it again this time it had a very distinct crackling noise the and had almost no power. so i shut it down and and checked oil it, was ok. so against my better judgment i hoped back on it and rode back to the trailer about 400 feet or so and shut it off and went home upset. so now my thought is that the plug was only half firing, or the carbs got screwed up and was only working off one, kinda ruled that out seems really unlikley. or the most likely that i can think of is that i burnt up a exhaust valve and im lossing compression so thats where the sound and loss of power are coming from IMO. so tell me what you think you guys are the shiz'nit.