I just bought a 2003 660 grizzly and I'm wondering what oil to use in it. I keep seeing online people saying it has a wet clutch. I always thought they were belt driven. If belt driven can I just use regular car oil in it

 

Yamaha's are belt driven. but they have a wet clutch inside so when you let off the gas instead of the belt slipping and burning it up on the primary, the sheave stops rotating.
look into rotella t6 oil. I run it and tons of other guys use it in their quads with great results.. do not run regular motor oil...

 

I also use Rotella T6 in all my Atv's and motorcycles.