Yamaha RS90GTZ Service Manual page 87

CLUTCH
High altitude tuning
Atmospheric pressure decreases and engine
output becomes low at high altitude locations.
Because of this, clutch engagement speed and
shifting speed also decrease and unable to
maximize the engine output power. To maxi-
mize the engine output, tuning for increasing
clutch engagement speed and shifting speed
is necessary. This setting is called high altitude
tuning.
The following changes are usually performed
in high altitude tuning.
• To increase the clutch engagement and shift-
ing speed, changing to a larger spring con-
stant or using lighter weights and rivets.
(decreasing primary sheave thrust)
• Increasing the reduction ratio of the driven
gear/drive gear. (increasing the driving per-
formance)
Refer to "HIGH ALTITUDE TUNING".
Engine speed
Speed at maximum output
Low speed
Distance travelled
2-64
INSP
ADJ