BOMBARDIER 1996 Ski-doo MX Z440 Handbook page 56

Section 03 CHASSIS PREPARATION
The large shims are only able to deflect .203 mm instead of .610 mm thus reducing the flow area of
the piston. This will result in the same low speed dampening, but the medium and high speed
damping will be increased. The following graph represents the effect of changing the total
thickness of small shims which determine the-amount-of large shim deflection.
,
As you can see, low speed dampening remains the same until the shim stack bottoms out against
the valve stopper. Then the dampening becomes significantly stiffer. This is sometimes referred to
as progressive dampening. Another similar way to achieve this type of dampening is to use
multiple stacks of large and small shims.
, A06F1TS
1. Piston
03-40
.114 mm
T
o
o
Piston speed
– .342 mm
/
Large shims
do not touch
valve stopper
- -