Yamaha RS90GTZ Service Manual page 88

Parts that affect transmission characteristics
Among the components of the V-belt transmission, those that have direct impact on the shifting
function are described below.
Part
Primary sheave
Spring
Weight
Element
Preload • A larger preload increases the clutch engagement
speed, and the shifting speed tends to rise
accordingly. Shifting tends to become somewhat
harder. (increasing the spring reaction force)
• A smaller preload decreases the clutch engage-
ment speed, and the shifting speed tends to drop
accordingly. Shifting tends to become somewhat
easier. (decreasing the spring reaction force)
Spring rate • A larger spring rate increases the shifting speed. It
also slightly increases the clutch engagement
speed. Shifting tends to become somewhat
harder. (increasing the spring reaction force)
• A smaller spring rate decreases the shifting
speed. It also slightly decreases the clutch
engagement speed. Shifting tends to become
somewhat easier. (decreasing the spring reaction
force)
Shape, weight Shape and weight determine, the size of moment
about the center of the weight rotation when the
sheave is running.
• Heavier weight decreases the clutch engagement
and shifting speed. Shifting tends to become
somewhat easier. (increasing the sheave thrust)
• Lighter weight increases the clutch engagement
and shifting speed. Shifting tends to become
somewhat harder. (decreasing the sheave thrust)
2-65
INSP
CLUTCH
ADJ
Impact on the shifting function