my brother bought a 07 Kodiak 450 4x4 it ran great for the first day of riding this long weekend but then started to act up. I am in H and throttle right down and can only get up to 40-47km/h the first day out i was getting up to 80km/h. we took off the case to look at the belt and drain the water and mud but there wasn't much just some dry clumps on the bottom of the case. the belt seemed OK but i didn't take a really good look at it.

 

Put the ATV in neutral and watch the clutches in action to make sure everythings working ok.
The belt should sink into the larger driven clutch and raise on the drive clutch when you give it gas like this video. Better yet ride it and watch the clutch work but dont get you foot to close.

 

I was able to do this and noticed that it doesn't move up and down like in the video they just spin no in or out motion. What would be my next step for diagnosis and hopefully fix