Adjusting Ride Height - BRP ski-doo MX Z X 440 RACING Handbook

SECTION 03 - CHASSIS PREPARATION
1. Hold bleeder adaptor while opening bleeder
2. Clear hose to catch used brake fluid
Pump a few time brake lever and while holding
brade lever depressed, open bleeder and check
for air to escape.
Repeat with the same bleeder until no air appears
in hose.

ADJUSTING RIDE HEIGHT

A cross-country racer will want all the suspension
travel you can for a rough snowcross-type event.
But when racing a high speed event on a relatively
smooth lake, giving up some of the suspension
travel to lower the machine is advantageous. Low-
ering the machine, reducing the ride height, does
3 things for you:
1. Lowers the center of gravity of the machine;
which improves cornering.
2. Reduces the frontal area of the sled; which im-
proves aerodynamics.
3. Reduces the approach angle of the track; which
reduces drag.
A person wanting to lower the machine for a short
event like a radar run may simply chain or strap the
machine down. Provided the course is quite
smooth, this can work, but realize that strapping
down the suspension preloads the springs highly
and the ride will be very stiff. This technique is not
recommended for most forms of racing.
The most common technique for lowering the ma-
chine is to use shorter springs or to shorten the
existing springs by heating and collapsing a coil or
2 of the spring as needed. Realize that shortened
springs will have very little preload when the sus-
pension is in its "topped out" position, and it may
be necessary to safety wire the spring collars into
position, and use additional limiter devices like
straps, chains to limit the extension of the shock.
03-30
NOTE: Some race organizations do not allow short-
ening springs so a proper optional short spring
would be used.
Lowering the Front Suspension
Make limiter straps from standard rubber limiter
strap material or link chain and go from shock bolt
to shock bolt (longer shock bolts will be required).
The length of the strap should be adjusted to ob-
tain the desired ride height. Most rules require you
to maintain 2 inches of suspension travel.
Shorter springs should be used to avoid excessive
preload.
On vehicles with rebuildable shocks (HPG T/A), a
spacer can be installed internally on the shock
shaft to limit the shock extension. Spacers can be
fabricated from 1 in O.D. aluminum round stock.
(Refer to the shock rebuilding section for proper in-
stallation procedures).
The threaded adjusters can be loosened to provide
the desired amount of spring preload.
Lowering the Rear Suspension
Option 1: The rear suspension can be lowered by
compressing the rear scissors to the desired ride
height and installing a strap to maintain this height.
Compressing the rear scissors adds a great deal
of preload to the rear torsion springs. Use softer
springs.
Option 2: It is also possible to lower the rear sus-
pension on vehicles equipped with HPG T/A shocks,
by using a spacer to limit shock extension.
2
1
A03F0QA
1. 1 st hole
2. 2 nd hole
A. 11 N•m (97 lbf•in)
A
MMC2005-001_03A.FM