Change In Amount And Characteristics Of Fork Oil; Setting Of Spring After Replacement - Yamaha WR450F 2021 Owner's Service Manual

on the rider's feeling of an actual run and the cir-
cuit conditions.
The front fork setting includes the following three
factors:
1. Setting of air spring characteristics
• Change the fork oil amount.
2. Setting of spring preload
• Change the spring.
3. Setting of damping force
• Change the compression damping force.
• Change the rebound damping force.
The spring acts on the load and the damping
force acts on the cushion travel speed.
EAM30172
CHANGE IN AMOUNT AND
CHARACTERISTICS OF FORK OIL
Damping characteristic near the final stroke can
be changed by changing the fork oil amount.
EWA19190
WARNING
Adjust the oil amount in 5 cm³ (0.2 US oz, 0.2
Imp.oz) increments or decrements. Too
small oil amount causes the front fork to pro-
duce a noise at full rebound or the rider to
feel some pressure on his hands or body. Al-
ternatively, too large oil amount will cause
the air spring characteristics to have a ten-
dency to be stiffer with the consequent dete-
riorated performance and characteristics.
Therefore, adjust the front fork within the
specified range.
Recommended oil
Yamaha Suspension Oil S1
Standard oil amount
285 cm³ (9.64 US oz, 10.05
Imp.oz)
Extent of adjustment
260–365 cm³ (8.79–12.34 US oz,
9.17–12.87 Imp.oz)
A. Air spring characteristics in relation to oil
amount change
B. Load
C. Stroke
1. Max. oil amount
2. Standard oil amount
3. Min. oil amount
EAM30173
SETTING OF SPRING AFTER
REPLACEMENT
As the front fork setting can be easily affected by
the rear suspension, take care so that the front
and the rear are balanced (in position etc.) when
setting the front fork.
1. Use of soft spring
• Change the rebound damping force.
Turn out one or two clicks.
• Change the compression damping force.
Turn in one or two clicks.
TIP
Generally a soft spring gives a soft riding feeling.
Rebound damping tends to become stronger
and the front fork may sink deeply over a series
of gaps.
2. Use of stiff spring
• Change the rebound damping force.
Turn in one or two clicks.
• Change the compression damping force.
Turn out one or two clicks.
10-2
CHASSIS