Polaris 2001 High-Performance Snowmobile Service Manual (PN 9916690), Page 294Get this manual
REAR SUSPENSIONTRACKTRACTION Shock Valving
To check high speed rebound, drive over series of fairly large mogulsGradually increase the speed until you reach 70 to 80 of maximum vehicle speed or the maximum safe speed for the vehicle over those bumps(The reason for limiting speed is that it is difficult to feel what the shocks are doing when you are driving at full speed Ideal high speed rebound is achieved when your suspension keeps returning fast enough to have full travel as you hit the next bumpIf the first bump feels good, but each bump after that gets worse until the machine starts bouncing around, you need less high speed rebound damping in the shocks that are bouncingAfter you've determined your high speed rebound valving needs, drive over one large rounded bump to make sure you have enough rebound control to keep the sled from kicking up after you hit the bumpTo check the high speed compression damping, you will need to find hard, square edged bumpAgain, try to hit the bump at less than full speed so you can feel what each shock is doingThe ideal compression valving prevents bottoming, but is not too harshWhen you hit the bump, if your suspension falls through and bottoms, you need more dampingIf the sled bounces when you first contact the bump, you need less damping