Arctic Cat Sno Pro 120, Service Manual

Page: 353 / 470

7-3
7
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 SKI 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: The shocks should not be under load when
adjusting.

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; then 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).
2. 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).
3. To increase air pressure in the shock, pump until
desired pressure is attained.
4. Remove the pump valve from the shock air valve.

NOTE: As the pump valve is being removed from
the shock, the sound of air loss is from the pump
hose, not from the shock.
5. Install the air valve cap onto the shock.
FRONT ARM SPRING TENSION
Having very light front arm spring tension is desirable.
When riding in 4 in. or more of snow, the machine will be
quicker if the front spring tension is adjusted lightly.
If the spring tension is adjusted too stiff, the track angle
at the front of the skid frame is steep. This steep angle
prevents the snowmobile from getting up on plane and
slows down by 5 to 8 mph. Also, the following could
occur.
1. Slows machine down in loose snow.
2. Causes the snowmobile to dart and dive as a result of
less track on the ground on deceleration.

NOTE: A tight front arm works well under only two
conditions: sticky snow conditions in the spring of
the year and in hill climbing on hard packed snow.
With the front arm adjusted too soft, the spring may
come off the roller.
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 trans-
ferred back quicker. The problem with too much front arm
spring tension is that the feel of the snowmobile becomes
very short. The reason for this is the front arm becomes the
pivot point between the spindles and rear of the snowmo-
bile. 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 cen-
ter of gravity is transferred forward.
A method for adjusting the front spring tension follows.

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
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.