Bumping this back up as i have the same problem

 

my nephew is having an issue with his 2002 (I posted another post about it) wondering if its the same situation with him

 

if your looking at your primary clutch(engine clutch) you will see the jam nut once you remove the clutch cover(6 bolts on the outside and center bolt) and spring. here is a break down and the nut is #9.
http://parts.polarisind.com/Assemblies.asp
if you get an error on page, just click on the drive clutch to view it.

 

Common problem for the plastic jam nut to back off and limit clutch travel and speed. If you find this is the problem use blue loctite on the shaft threads and just lightly stake the nut snug. Not too much pressure or you will crack it. Later clutches had the metal jam nut ,but had some do the same thing and back off. Just do the same as the plastic nut and loctite it. Hopefully this is the problem as stendori mentioned. OPT

 

dang i wish i didnt just silicone my clutch cover back up. I want to say when i did my clutch kit there wasnt a nut on there at all. It goes in and out but tops out very quick in high and low. Always has. There is a plastic piece on there that is bigger but didnt seem like there was anything to grab to tighten it up.