Front Suspension; Fork Springs - Honda CRF450R Owner's Manual

6. SUSPENSION ADJUSTMENT

FRONT SUSPENSION

The fork should always be adjusted for the rider's weight
and track conditions by using one or more of the fol-
lowing methods.
Basically, there are four adjustments you can make to
the front suspension:
• Fork springs – Optional spring is available in softer
and stiffer types than the standard rate. (page 10)
• Rebound damping – Turning the rebound damping
screw adjusts how quickly the fork extends.
• Compression damping – Turning the compression
damping screw adjusts how quickly the fork com-
presses.
• Oil volume – The effects of higher or lower fork oil
level are only felt during the final 3.9 in (100 mm) of
fork travel.
NOTE:
• Air is an unstable gas which builds up pressure as it
is worked (such as in a fork). Air pressure acts as a
progressive spring and affects the entire range of
fork travel. This means the fork action on your CRF
will get stiffer during a race. For this reason, release
built-up air pressure in the fork legs between motos.
Be sure the fork is fully extended with the front tire
off the ground when you release the pressure.
74
NOTE:
• The inverted fork on your CRF features sealed damper
cartridges with dual (separate air and oil) chambers
to prevent aeration. The design also isolates the oil in
each fork tube/slider, which may contain air bubbles
and/or metal particles, from the sealed cartridge to
provide more consistent damping.
1
2
(1) COMPRESSION DAMPING ADJUSTER
(2) REBOUND DAMPING ADJUSTER

Fork Springs

The fork springs in CRF's are about right for riders
weighing between 150 and 160 Ibs (less riding gear).
So if you're a heavier rider, you have to go up on the oil
level or get a stiffer spring. Do not use less oil than the
minimum specified for each spring or there will be a
loss of rebound damping control near full extension. If
the fork is too hard on big bumps, turn the damping
adjuster counterclockwise 1-turn and lower the oil level
in increments of 0.2 oz (5 cc) in both fork legs until the
desired performance is obtained. Do not, however,
lower the oil level below the minimum oil level.
Minimum oil capacity:
Standard spring: 10.9 US oz (322 cm
Softer spring: 10.8 US oz (319 cm
Stiffer spring: 10.7 US oz (316 cm
NOTE:
• When adjusting oil levels, bear in mind that the air
in the fork will increase in pressure while riding;
therefore, the higher the oil level, the higher the
eventual pressure of any air in the fork.
Oil capacity 14.2 US oz (419 cm
(MAX)
1,800
1,600
Oil capacity 13.9 US oz (412 cm
1,400
(STANDARD)
1,200
1,000 Oil capacity 10.9 US oz (323 cm
(MIN)
800
600
400
200
0
30 60 90 120 150 180 210 240 270 300
Stroke (mm)
3 )
3 )
3 )
3 )
3 )
)
3