funny story for you all. i replaced the clutch with a heavy duty one and it the instructions said to run 30wt motor oil only. started slipping with only 30 hours on it at a local atv event. up to this point i had only run atf until i replaced the clutch. well i still had 2 more days to ride so i ran and got a few qts of atf and tipped the bike on its side to keep the coolant in and took the clutches out and soaked them in a little gas, cleaned everything else up put it back together with some atf after flushing out the gearbox and no sliipage at all. beat the hell out of it all weekend with no problems.