Snowmobile Arctic Cat 2-Stroke (2007 year). Manual - part 122

9-1

9

SECTION 9 — TRACK/REAR 

SUSPENSION

TABLE OF

CONTENTS

Understanding the Suspension ............................... 9-2
Suspension Setup Basics ....................................... 9-3
Suspension Mounting Location Chart ..................... 9-6
Torque Specifications .............................................. 9-6
Chassis and Skid Frame 

Mounting Locations.............................................. 9-7

Servicing Chart ..................................................... 9-10
Repair Procedure 1 ............................................... 9-10
Repair Procedure 2 ............................................... 9-40
Repair Procedure 3 ............................................... 9-72
Repair Procedure 4 ............................................. 9-104
Drive Sprocket Locations .................................... 9-133
2007 Idler Wheel Selection Chart ....................... 9-137
2007 Non-Rebuildable Shock Absorber

Specifications Chart ......................................... 9-137

2007 Front Suspension Ski Springs

Specifications Chart ......................................... 9-138

2007 Front Suspension Sway Bar

Specifications Chart ......................................... 9-138

2007 Rear Suspension Specifications Charts..... 9-138
Shock & Spring Chart - 2007 Models.................. 9-139
2007 Track Specifications Chart.......................... 9-140
Track Warranty Guidelines .................................. 9-140
Rebuildable Shock Tools Required...................... 9-141
2007 Rebuildable Shock Specifications .............. 9-141
Servicing ACT Shock .......................................... 9-145
Servicing Position Sensitive Shock ..................... 9-148
Rebuilding/Recharging Fox Air Shocks ............... 9-152
Servicing Fox Zero Pro Shock Absorbers ........... 9-158
Shaft Eyelet ......................................................... 9-163
Pressurizing Rebuildable Shocks ........................ 9-163
Troubleshooting Track ......................................... 9-164

9-2

Understanding the Suspension

GENERAL

Quick acceleration and the ability to go through the

turns with power are the most important handling

qualities. This section explains how the skid frame

functions to provide these two important handling

qualities. Before proceeding, however, note these

terms.

Weight Transfer — A shift in the center of gravity in

any direction depends on the force applied.

Track Tension — The amount of tightness or loose-

ness of the track when correctly mounted in the chas-

sis.

Spring Tension — The amount of force exerted on the

spring by either fork tension adjustment or eyebolt

adjustment.

Ski Pressure — The amount of force exerted down-

ward on the skis.

Good weight transfer characteristics are needed for

fast acceleration (shift of weight from skis to track)

and for cornering (shift of weight back to skis to hold

the front end in turns). Effective weight transfer

depends on suspension tension, position of rider, and

the position of the front arm limiter.

To understand how the suspension system works, think

of the entire system in terms of three points; the skid

frame rear axle center, the skid frame front arm, and

the ski saddle center.

Assume that the front arm functions as a stationary

pivot point between the rear axle center and the ski

saddle center. Also assume that the ski saddle center is

the same height off the ground as the rear axle center.

This produces the standard position arrangement.

0728-180

Under acceleration when the center of gravity is trans-

ferred to the rear of the machine, the rear suspension

collapses slightly. This brings the rear arm point down-

ward and with the front arm stationary, the teeter-totter

effect reduces the pressure on the skis, position A.

However, for controlled cornering, more pressure is

needed on the skis. So when the driver decelerates

coming into a corner, the center of gravity is trans-

ferred forward, putting the required pressure onto the

skis and reducing the pressure on the rear suspension,

position C.

0728-181

This is essentially what weight transfer is all about —

the shift of weight to the rear of the machine for posi-

tive traction and good acceleration or to the front of the

machine for positive handling and cornering control.

9-3

9

Suspension Setup Basics

FRONT ARM SPRING TENSION

„NOTE: Read the following information closely as
it pertains to all suspensions used in the last sev-
eral years.

It is desirable to run with very light front arm spring

tension. 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.

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

snowmobile 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 basi-

cally 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

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

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 if desired. This

adjustment must be made to suit driving style and some

test driving time. With the rear arm in its present mount-

ing location, no advantage has been noted from chang-

ing 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 there is a need to make changes, there are

several spring and shock sizes to choose from. While

making these changes, keep the following 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 accelera-

tion 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 decelera-

tion, 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.

! 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.

9-4

ADJUSTING FRONT SHOCKS 
(Fox Air Shocks)

The air shocks are individually adjustable for the terrain

conditions and driving style of the operator. The shocks

are initially preset at 4.6 kg/cm

2 

(65 psi) on the Cross-

fire Sno Pro/F-Series Sno Pro and 4.2 kg/cm

2 

(60 psi)

on the M-Series Sno Pro; however, it is possible to “fine

tune” the shocks to match the operator’s weight, riding

style, and terrain conditions.

„NOTE: Care should be taken to have equal pres-
sure in the shocks before operating the snowmo-
bile.

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 Air Shock Pump (p/n 2603-

614) onto the shock air valve approximately six

rotations.

„NOTE: As the pump is being attached to the
shock, the hose will fill with air. This will result 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 releas-
ing it will allow only a small amount of air to
escape (micro-adjust).

4. To increase air pressure in the shock, pump until

desired pressure is attained.

5. 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.

6. Install the air valve cap onto the shock.

FRONT ARM SPRING TENSION 
TOO STIFF

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.

REAR ARM SPRING TENSION

The rear spring tension is adjusted for the weight of

the driver. There are three possible adjustments.

1st block position - set for up to 150 lb

2nd block position - set for 150 to 200 lb

3rd block position - set for over 200 lb

727-720A

REAR ARM MOUNTING POSITION

(Between Rails)

There are several mounting holes found in the rails for

installing the rear arm.

The holes have been added to the suspension to pro-

vide adjustment to fine-tune the suspension to driving

styles.

If the ride is too soft, moving the rear arm back

between the rails will stiffen the ride. By moving the

rear arm forward, it will collapse quicker and allow

more transfer of weight to the back of the suspension.

This will also affect the handling by providing a softer

ride and also easier steering.

The drawbacks of moving the rear arm forward are

that the suspension may bottom out quicker and some

travel is lost.

„NOTE: When making any changes to the front or
rear suspension, the change should be made at
both ends to keep the suspension balanced. For
example, installing stiffer springs in front may
require installing the next step stiffer spring in
back to keep everything in balance.

! WARNING

Do not exceed 105 kg/cm

2

 (150 psi) in the shock.