I recently bought a 2007 sportsman 450. On test drive all was well but after I got it home and put some time on it out on the trails it started to creep and I am unable to move the gear selector while running. It shifts fine when it’s cold but every time it gets warmed up it does the same thing. I adjusted the shimming behind the secondary clutch or the "driven" so that when it idles cold it does not turn with the primary but it still does the same thing when it warms up after riding it around a little. Any thoughts help or ideas would be greatly appreciated. I should also say that the previous owner said he put a clutch in it and cleaned the belt new and the belt is not Polaris. He did give me the old Polaris belt with it.