Yamaha 2010 FX Nytro FX10X Service Manual page 425

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.
Shifting speed is defined as the engine speed
reached when the snowmobile has travelled
800 m (2,500 ft) after being started at full-throt-
tle 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 terrain), however, engine speed
may decrease after the shifting speed has
been reached.
Engine speed
Good condition
Shifting speed
Clutch engagement speed
Starting position
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.
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INSP
ADJ