Arctic Cat M 8000, Руководство по обслуживанию

Страница: 5 / 210

4
ENGINE
A normally aspirated engine will generate more horse-
power at sea level than it does at higher altitudes. The
reason is that the higher you go, less oxygen is available
for the engine to use during its combustion process. Less
oxygen means it needs less fuel to obtain the correct
air/fuel ratio to operate properly. This is why the fuel
ratio has to be recalibrated. High altitude engines operate
as though they have a lower compression ratio. This,
along with less oxygen and less fuel, means that the
engine generates less horsepower. All of these character-
istics will become more evident the higher the altitude.
SUSPENSION
The different riding styles of the individual operator, the
varying snow conditions, and the type of terrain are all
factors that affect the suspension at high altitude. Trail
riding versus powder snow riding versus combination
riding will all require different suspension settings.
The normal setting for front ski suspension is as little spring
pre-load tension as possible for powder snow riding allow-
ing the skis to float across the snow with the least amount
of resistance. Trail riding will require more spring tension
to carry the varying load more effectively. Many different
settings and spring tensions to consider exist when adjust-
ing for riding style and snow conditions.
The rear suspension has a number of spring settings that
produce different riding characteristics.
The front arm spring and shock will also affect the ride
and handling when either on a trail or in powder snow. A
strong spring setting on this shock will cause the snow-
mobile to tend to “dig” more when riding in the powder
snow rather than climbing up on top of the snow. But, it
will work more effectively when riding on a trail. A
softer spring setting will allow the front of the rear sus-
pension to collapse much quicker and change the angle of
the track to the snow. A more gradual angle will tend to
raise the snowmobile up on the snow rather than digging
into it.
Many possible variables and adjustments to the rear sus-
pension exist depending on snow conditions, riding style,
and type of terrain. These adjustments can be made to
individualize the snowmobile to the riding style of the
operator.
As snow cover and riding conditions change, several dif-
ferent adjustments can be made to change the ride and
handling characteristics for operator preference. Located
on the front suspension arm are limiter straps. They limit
the amount of “fallout” the front arm can have. These
straps may be adjusted in or out due to conditions and
riding style. The more the straps are brought up, the more
steering power the operator has due to the amount of ski
pressure.
Another adjustment that can be made on the rear suspen-
sion is the front arm shock spring tension. As trail condi-
tions change, the spring pre-load may be used to decrease
the chance of the front end “bottoming out.” With a
stiffer spring pre-load, the ride of the snowmobile will
improve on the trail but will affect the performance in the
deep powder snow. In deep powder snow, the stiffer
spring pre-load will cause the front-end to “dig” and pos-
sibly take longer for it to plane off. Several different-rate
springs are available for different riding styles and terrain
conditions.
On the standard models, the front shock springs are also
individually adjustable for the terrain conditions and
driving style of the operator. The spring adjuster has been
set at the factory so the correct amount of threads are
exposed between the spring adjuster and the shock hous-
ing as an initial setting. Additional ski pressure can be
obtained by tightening the spring tension; ski pressure
can be decreased by relaxing spring tension. Springs with
different spring rates are available for operator choice
and snow conditions.
A limit exists as to how far you can pre-load the springs
before “coil bind” takes effect where the wire on the
spring actually runs into itself and causes binding. Equal
adjustments should be maintained on both sides of the
snowmobile. On the Sno Pro models with float shocks,
they are individually adjustable for the terrain conditions
and driving style of the operator. The shocks are preset at
the factory (see chart) as an initial setting; however, it is
possible to “fine tune” the shocks to match the operator’s
weight, riding style, and terrain conditions.
Checking and adjusting air pressure must be done at rid-
ing temperature (outside) and shocks are at full extension
with no weight on the shock. Also, it is advisable to
check air pressure when the outside temperature varies
more than 25°.

NOTE: Care should be taken to have equal pressure
in the ski shocks before operating the snowmobile.
Finally, track tension should be looked at to make sure
that it is within recommended specifications to affect the
efficiency of the snowmobile. On models with the torque
sensing link, the track is actually tightening as the sus-
pension moves through its range of motion causing the
track to sag in the middle and rub on the top part of the
rear suspension arm.
TRACK
Carefully matching the riding requirements to the type of
track will ensure the maximum use of all available engine
power. Lug height and track durometer are the two main
concerns when selecting a track for various riding styles.
Tracks exist with lug heights from 1.0” up to 3.0” to
accommodate various snow conditions. Generally, the
deeper the snow, the taller the lug. It must be noted that
the installation of any deep-lug track may reduce top end
speed and promote premature wear strip wear in marginal
snow conditions.
Initial Setting Chart
Model
Front Shock
(Ski)
Front Arm
Shock
Rear Arm
Shock
XF/ZR Sno Pro 60 psi N/A N/A
XF HC/M Sno Pro 95 psi N/A 130 psi
M LTD 90 psi (Main
Chamber)
150 psi (Evol
Chamber)
50 psi (Main
Chamber)
125 psi (Evol
Chamber)
150 psi (Main
Chamber)
250 psi (Evol
Chamber)
ZR RR 100 psi (Main
Chamber) 200 psi
(Evol Chamber)
N/A N/A