I have a Kodiak 450 and on my first oil change I put in Valvoline 10w-30. I also run a Puralator oil filter and I have not had any problems in the last year. I refuse to pay the outragous prices that Yamaha wants for their crap fluids and oil filters. I have cut a Yamaha filter in half and was not impressed with the cheap materials it was made of. After cutting up a couple, Puralator had the best type filter for my bike. I now run this in all my bikes

 

I don't use synthetic because it works too well, it will coat the disks and they won't have enough friction to operate properly. I use oil that doesn't have additives to increase fuel economy, the friction additives will also prevent the clutches from working properly. Yahama oil isnt synthetic unless you buy the spendy stuff, and they want you to use it because it doesn't have all the friction additives automotive oils have.

You can use synthetics if you can find them without friction additives, friction modifyers or whatever. I suggest you buy ATV 4 stroke oil if you want to use synthetics, or buy petrolum oils and read the back to make sure it doesn't have friction modifyers and such. Stay away from automotive synthetics.

check these quotes from various manufactuers of aftermarket oils:

"AMSOIL Synthetic Motorcycle Oils contain no friction modifiers, making them ideal for motorcycle and ATV engines. The friction modifier free formulation of AMSOIL ensures dependable starting, smooth running, good fuel efficiency, desirable stall speeds and clutch compatibility."
Taken from here

This might be good oil too click 'how it works' on the left side bars.
The wet clutch system, high torque and loads, and the extreme operating environments of ATVs require an oil with special properties for proper performance and protection. Valvoline formulated ATV oil to meet the specific demands of ATV applications, providing the proper frictional properties for the wet clutch system and the film strength for high running temperatures

 

thanks for all your info, dirty dude, i might try amsoil once

 

The "Red Cap" Mobil 15w-50 is the only one that does NOT have friction modifiers. Making it wet clutch safe.

 

Here's what I'm using in my Kodiak. Acroding to them it's the right one. I'v had it in for about 225 miles and no problems. about $7 at Auto zone.

 

I am running the red cap now changed oil last week and it works great

 

I forgot to post this http://www.mobil1.com/motorcycle/index.jsp
I have yet to see anything showing this RED CAP.
It's not on Mobils site that I can find.

 

The Mobil 1 "Red Cap" is simply the plain 'ol 15W-50 automotive synthetic oil.