i have never had venting problems with my stock 700. i changed the belt as needed but never actually blew a belt. the 700 flat out rips! i just replaced the motor last year and put about 150 miles on it compared to a stock xp 800 it runs about equal. the sled has about 10,000 miles on it, the motor got changed under warranty at about 2000 miles just because it had a vibration issue. i got about 8000 to the second motor and it blew a rod bearing but even when that happened it still ran 100%. they are awesome sleds! and my dad owned a couple 800 dragons and they would still be the strongest running 800 without the updates and they never really had problems as long as they were ridden the way they were supposed to.