the sled was raced in cross country twice and already shredded two belts
whats the problem?
how to fix it?

Properly align your clutching!!

Check your motor mounts... buddy had the same problem..finally found out the mounts were torn from the belly

The problem is chassis alignment. Bad batch of bulkheads that when mounted to the tunnel are "off" a couple mm s which screws up the clutch alignment which isn't adjustable on the XPs. You can mess with your motor mounts (shimming / slotting) or you can get that kit from Team Industries so you have normal (removable) secondary setup and then just add or take away washers from the backside of the secondary like normal. Or, this one guy has a QRS shim kit which would probably be the easiest / cheapest fix.

http://www.dootalk.com/forums/index.php?showtopic=221162

You shouldn't have to mess with anything, take it back to the dealer and have them fix the problem, its a new sled........