Periodic maintenance and adjustment
68
6.
Lift up the air filter element frame and
check the air filter element. If there is any
snow on the air filter element, remove the
element, brush off the snow, and then in-
stall the air filter element.
7.
Place the air filter element frame in the
original position, and then install the air
filter case cover.
8.
Hook the fasteners onto the air filter case
cover.
9.
Connect the air temperature sensor cou-
pler and install the headlight unit stay
quick fasteners.
10. Install the right side cover, the left side
cover, and the shroud.
ESU11931
High-altitude settings
Operating at high altitude reduces the perfor-
mance of a gasoline engine about 3% for ev-
ery 305 m (1000 ft) of elevation. This is
because there is less air as altitude increases.
Less air means less oxygen available for
combustion.
Your snowmobile utilizes an electronic fuel in-
jection system that delivers the optimal air/fu-
el ratio required by the engine. Therefore, the
fuel injection system does not need to be ad-
justed, even for operation at high altitude.
Remember:
Less air at higher altitude means there is less
horsepower available, even with the optimal
air/fuel ratio. Expect acceleration and top
speed to be reduced at higher altitudes.
To overcome operating with less power at
high altitudes, your snowmobile may also re-
quire different settings for the drive chain
gears and V-belt clutch to avoid poor perfor-
mance and rapid wear. If you plan to operate
your snowmobile at an altitude different from
the area where you bought it, be sure to con-
sult a Yamaha dealer. The dealer can tell you
if there are any changes necessary for the al-
titude where you plan to ride.
NOTICE:
The
drive chain gears and V-belt clutch should
be adjusted when operating above a high
altitude of 900 m (3000 ft). Consult a
Yamaha dealer.
[ECS00431]
ESU11950
Valve clearance
The valve clearance changes with use, result-
ing in improper air-fuel mixture and/or engine
noise. To prevent this from occurring, the
1. Air filter case cover
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