We have a 2008 Polaris Sportsman 500 and it's been running real bad. It's fine until you punch the throttle and then the rpm's shoot up but you don't accelerate any faster. I've replaced 2 drive belts in our Polaris Magnum as it has 5300 miles so I tore the Sportsman apart assuming the belt was shredded. Turns out, the belt is in perfect condition. Now I'm stumped. We plow a lot of snow with it in the winter time and it has about 1500 miles right now. What could be the problem considering the drive belt is perfect? Thanks for your help!