High-Altitude Settings; Valve Clearance - Yamaha VK PROFESSIONAL-II 2016 Owner's Manual

1. Place the snowmobile on a level surface
and apply the parking brake.
2. Open the shroud.
3. Remove the air filter case cover by un-
hooking the case cover fasteners.
2
1. Air filter case cover
2. Air filter case cover fastener
4. 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.
Periodic maintenance and adjustment
5. Place the air filter element frame in the
original position.
6. Install the air filter case cover by hooking
the fasteners.
7. Close the shroud.
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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.
2
Less air means less oxygen available for
combustion.
Your snowmobile utilizes an electronic fuel
injection system that delivers the optimal
air/fuel ratio required by the engine. There-
fore, the fuel injection system does not need
to be adjusted, even for operation at high al-
titude.
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.
ESU11951

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
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