This season I got a new to me 2018 axys 800 and its blown 2 belts within 100 miles. The only reason I have to believe that it isn't balanced is because I removed the electric start and the electric start ring around the primary. The first belt blew when I was climbing a hill on a deep day so I just figured that I didn't let if cool down enough. The next time I went riding it was fine all day and I had stopped to help someone get unstuck and by the time we were done I had to wait for the engine to get back up to temp so I figure the belt was plenty cool. It was also -5 f in that area but if anything cold weather helps belt life. So I did a couple short climbs on the way back then my cousin wanted to drag race a stock axys 800 vs mine with a slp pipe, can and clutch kit. The lake wasn't very big with 6 inches of soft-ish on top of a hard layer but it was wind blown. We were almost to the end of the short lake then I blew a belt and went flying over the handle bars cartwheeling a couple times, landing about 20-30 feet from where the belt blew. Not sure how fast we were going, I'd estimate 50-60mph but it could be less because I survived without a scratch (but I'm still very sore). Both of the belts were used and I have no Idea how many miles they had but I have to assume something is wrong for them to go that close together. I could've been easier on them but I've ridden other 800's just as hard or harder with no issues. The only other problem I could think of is that the sled is clutched for 6000' and we stayed down low that day around 3000', so it would have been over revving, not sure if that will cause belts to blow.