has this happened to you please help?

[mike3577]

went riding last weekend put on 250miles with no problems even hit 106mph.went out to my buddies lake to do some lake racing and blew two belt within a half hour.by the way this is a 09 xtx.the belts are not snapping in two.the top layer of the belt is just peeling off.its not the cogg side its the top.nothing is rubbing the first one had 1600 miles on it the other was used but oem number.the lake had about 5 inches of packed down snow with the acasional powdery spots.i looked at the clutches and inbetween the primary where the belt rides was polished which is normal but on the spider side of the shaft thats inbetween the sheeves there was a about a eighth inch of none polished metal showing and this seems like that area should have been polsished as well but the spring look ok as far as i can tell with the clutch still on the sled good spring pressure when pushing on the spider side of the primary.no loose bushing either.the first belt caught the deflector thats on the bottom of the bellypan so i straightened it out and drilled a hole and bolted it down to the pan so that wasnt the problem on the second belt blow.has this happened to anyone please help thanx.what causes the top of belt to peel off.also the cluches didnt seem hot