2004-2005 660 Yamaha Rhino Factory Service Manual, Page 94Get this manual
CLEANING THE AIR FILTER CHECKING THE COOLANT LEVEL
cApply Yamaha foam air filter oil or other quality foam air filter oildSqueeze out the excess oilNOTE: The element should be wet but not drippingLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL