update: thanks to the lovely mouse that built a nest in the air intake for my belt it cooked the belt or I cooked the belt inside I found seeds acorns and fur, grass that was stuff that looked like graphite inside of the cover three cans of brake clean and some soap and water it was cleaned then air dried test rode with the cover off everything is good now. It's just as snappy like when it was new.

 

in May I bought a new 500 HO not thinking I was riding with the wife going up a hill in High gear and hotspotted the belt it would slip from time to time so what I did was went and got a new belt put it on and took a piece of fine sandpaper and went around the belt handsanding any "glazed" spots off of it I now carry that as a spare belt when I go riding (used to do this all the time on sleds in Minnesota and worked great)

 

Field mice are a problem down here,love to find the dark places they can make a nest. I've found em just about every where especially under the front panels where all the wires are. Found one curled uo nicely in his nest,thought he was sleeping! Picked him up by the tail with a pair of needle nose pliers,but he was dead. Either all the plastic off the wiring he made a mess of killed him or old age one! Glad you found the problem! Just put some bait around the atv if you have it stored in a barn or near open fields. Lot of farmers and ranchers down her do this,along with keeping dogs and horses away from the machines. They love to eat seats! OPT