I have a 2010 Polaris Sportsman 500 HO that I purchased a few days ago. It rides great. However, I started noticing that yesterday after riding it for about an hour, as soon as I put it in reverse, it would just cut off. It will start right back up with no problems but then turn off again as soon as I put it in reverse. I went out just now to ride it and it's still doing it. Any idea on what could be causing this?