Hi guys, I have found a lot of great advise on this site! I have not however found anything like my issue, not exactly anyway. I have a 98 Prairie 400 that wants to creep in forward and reverse. The old primary was pretty worn out, so I put a new (used) one on. It has a brand new belt and the clutch faces are good and shiny. It doesn't go fast by any means, and I can hold the secondary back with my hand so I know it isn't grabbing hard. I have tried to shim out the secondary to get a little more length around the primary, but that didn't help either. I also put new brakes on to hold it back, and it will hold. Sometimes when I let off the brakes it will start creeping and sometime I will hit a sweet spot and it will stop. Any thoughts would be great!

 

Most ATV's with a clutch setup like yours have shims in the secondary sheave. They can be added to loosen the belt, or taken out to tighten on the belt some. Sounds like you may need to add a shim or two. The service manual gives belt deflection specs and tells how much deflection each thickness of shim gives or takes away. If the deflection is not enough it will cause it to squeal and creep at idle as well as grind the gears when you put it in gear. I cant provide you with specs, but hopefully this does point you in the right direction.

edit... Found this video which goes into pretty good detail: