Arctic Cat Sno Pro 120 2011, Service Manual

Page: 371 / 535

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When riding in sticky snow (springtime or warm days) or
hill climbing on hard snow, it may be desirable to stiffen
the front arm spring tension. When this is done, weight is
transferred back quicker. The problem with too much
front arm spring tension is that the feel of the snowmo-
bile becomes very short. The reason for this is the front
arm becomes the pivot point between the spindles and
rear of the snowmobile. With dominant spring tension on
the front arm, the suspension is basically contacting the
snow from a point below the front arm to the skis or the
spindle pressure point. This makes for a very short and
darting snowmobile on the trail. This is especially true
when decelerating and the center of gravity is transferred
forward.
A good method for adjusting the front spring tension fol-
lows.

NOTE: On those models having a coil spring over
the front arm shock absorber, the spring tension
should be set as soft as possible when operating on
trails and in deep snow.
0729-662
FRONT ARM LIMITER STRAPS
Under no circumstances should the front arm limiter
strap be lengthened. If lengthened, it may cause shock
absorber travel problems.
The two limiter straps can be shortened to suit driving
style and some test driving time. With the rear arm in its
present mounting location, no advantage has been noted
from changing the strap length. If the front arm straps are
shortened, the result will be more ski pressure and
aggressive steering.
SKI SHOCK ABSORBER SPRINGS
The shock absorber springs have been matched to the
shock valving and rear suspension. These springs are the
result of hours of testing and comparison riding trying
many different combinations of springs and shocks. If
changes are necessary, several spring and shock sizes are
available. While making these changes, keep the follow-
ing points in mind.
Heavier Or Stiffer Springs
1. These will require shocks with more rebound con-
trol, or the front end will become like a pogo stick.
2. With stiffer springs, the front end will become more
aggressive in the corners as more weight will be
transferred to the skis when decelerating. Also, more
weight is transferred to the rear on acceleration and
can cause the rear shocks and spring to bottom out.
3. If the springs are too stiff for general riding condi-
tions and style, the ride comfort is gone.
Spring Tension Too Soft
1. Front end bottoms out; hard on front end parts.
2. Less aggressive steering in corners on deceleration,
and less weight is transferred to the skis because of
softer springs.
3. Less weight gets transferred to rear of the machine
upon acceleration.

NOTE: When softening the ski springs, also soften
the rear to match entire suspension.
ADJUSTING FRONT SHOCKS (Fox
Air Shocks)
The air shocks are individually adjustable for the terrain
conditions and driving style of the operator. The ski
shocks are initially preset at the factory (see Section 1).
However, the shocks can be “fine tuned” to match the
operator’s weight, riding style, and terrain conditions.

NOTE: Care should be taken to have equal pressure
in the shocks before operating the snowmobile.
To increase or decrease air pressure, use the following
procedure.

NOTE: Adding air pressure will increase the air
spring force; reducing air pressure will decrease air
spring force.
1. Remove the air valve cap from the shock.
2. Thread the valve of Shock Absorber Air Pump onto
the shock air valve approximately six rotations.

NOTE: As the pump is being attached to the shock,
the hose will fill with air resulting in a lower gauge
pressure 0.14-3.52 kg/cm
2
(2-5 psi).
3. To decrease air pressure in the shock, press the black
bleed valve button half way down and hold until
desired pressure is attained.

NOTE: Pressing the button fully down and releasing
it will allow only a small amount of air to escape
(micro-adjust).
CAUTION
If the ski shock spring is adjusted too loose, the
spring retainer may fall out. If the spring is adjusted
beyond specification, the spring will coil bind and
spring adjuster damage will occur.
! WARNING
Do not exceed 105 kg/cm
2
(150 psi) in the shock.
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