I have a 2004 600 twin. I am having problems with shifting. While it is not running most of the time I can run through all positions. While running at bout 1050rpm i can someties get through all the gear positions then for some reason i cannot. If i shut it off i can go through all the positions. I replaced the belt, observed the drive clutch which appears to function normally, belt is not in motion while idling, It is a mystery to me.