Yamaha RST90GTY, Service Manual

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9
INSP
ADJ
CLUTCH/GEAR SELECTION
The clutch may require tuning depending upon
where the snowmobile will be operated and the
desired handling characteristics. The clutch can be
tuned by changing the engagement and shifting
speeds.
Clutch engagement speed is defined as the engine
speed at which the snowmobile first begins to move
from a complete stop.
Clutch shifting speed is defined as the engine
speed reached when the snowmobile has travelled
800 m (2,500 ft) after being started at full-throttle
from a dead stop.
Normally, when a snowmobile reaches shifting
speed, the vehicle speed increases but the engine
speed remains nearly constant. Under unfavorable
conditions (wet snow, icy snow, hills, or rough ter-
rain), however, engine speed may decrease after
the shifting speed has been reached.
È
Engine speed
É
Good condition
Ê
Clutch shifting speed
Ë
Clutch engagement speed
Ì
Starting position
Í
Distance travelled 800 m (2,500 ft)
GEAR SELECTION
The reduction ratio of the driven gear to the drive
gear must be set according to the snow conditions.
If there are many rough surfaces or unfavorable
snow conditions, the drive/driven gear ratio should
be increased. If the surfaces are fairly smooth or
better snow conditions exist, decrease the ratio.
Gear ratio chart
The drive and driven gears and the chains shown in
the gear ratio chart are available as options. The
figures containing a decimal point represent the
drive/driven gear ratios, while the bottom numbers
designate the number of links in the chain.