Yamaha wr450f - Manual (Page 6)

6
5 0 0
4 5 0
4 0 0
3 5 0
3 0 0
2 5 0
2 0 0
1 5 0
1 0 0
5 0
0
F
o
r
c
e
k
g
f
Stroke mm
0 2 0 4 0 6 0 8 0 1 0 0 1 2 0
Oil level 100 mm Oil level 110 mm Oil level 120 mm Oil level 130 mm
In general, compression damping changes should
be used to influence the bike’s stability and re-
sponse, while rebound damping changes should
be used to influence comfort and traction.
When you need more damping force, you should
mainly try to increase compression damping and
use as little rebound damping as possible.
This usually means that you gain comfort and
performance in handling.
Oil level adjustment
As the air trapped between the oil and the top
nut acts as an air-spring, a change in oil level will
effect the damping forces. Not in the early stage
of fork travel, but a great deal in the later stage.
A general description of how the oil level/air-
spring effects the damping forces are shown in
Fig.4.
The air-spring gives the Öhlins USD fork a pro-
gressive spring rate, preventing it from bottoming
out hard.
By using different combinations of springs and oil
levels/air-springs you can alter the characteristic
of the fork and tailor it to suit different tracks and
conditions.
CAUTION!
The oil level must be the same in both front fork legs.
Riding a bike with different oil levels will cause
instability.
When the oil level is raised
The air-spring in the later half of travel is strong,
and thus the front fork hard.
When the oil level is lowered
The air-spring in the later half of travel is soft,
and thus the front fork soft.
CAUTION!
Adjust the oil level with the fork leg fully com-
pressed and no pre-load washer or spring installed.
NOTE!
See Mounting Instructions for recommended oil
level.
The oil level is measured from the top of the outer
leg, with the top nut off (Fig.6).
Changes in oil level should be made in small
steps. We recommend a change of 5 mm at a
time and not outside the range of 80-130 mm.
Oil level
5.
Oil level is measured
from the top of the
outer leg, with the top
nut off,the fork fully
compressed and no
pre-load washer or
spring installed.
Oil level
Force
Stroke
Air spring
4.
A change in oil level
will effect the damp-
ing forces, not in the
early stage of fork
travel but a great
deal in the later
stage.