Honda CRF450R 2011 Owner's Manual page 142

5. Measure the loaded without rider dimension.
Do this with your CRF set at the standard race
sag.
BIKE LOADED MEASUREMENT
(without rider)
EXAMPLE: 550 mm (21.7 in)
Example:
Unloaded = 600 mm (23.6 in)
– Loaded = 550 mm (21.7 in)
= 50 mm (2.0 in)
Sag
(Without Rider)
6. Calculate the free sag dimension.
To do this, subtract the loaded without rider
dimension (step 5) from the unloaded
dimension (step 2).
Free sag indicates the distance your rear
suspension should sag from the weight of the
sprung portion of your CRF.
With the spring pre-load set to obtain the
proper race sag, the rear suspension should sag
10 to 25 mm (0.4 to 1.0 in).
If the rear of your CRF sags less than 10 mm
(0.4 in) from its own weight, the spring is too
stiff for your weight. As it is not compressed
enough, reduce the spring pre-load or replace
the shock spring with a softer spring.
Spring Rates
If you are lighter or heavier than the average rider
and cannot set the proper ride height without
altering the correct spring pre-load, consider an
aftermarket rear shock spring.
A spring that is too soft for your weight forces you
to add excessive spring pre-load to get the right
race sag and, as a result, the rear end of the
motorcycle is raised. This can cause the rear wheel
to unload too much in the air and top out as travel
rebounds. The rear end may top out from light
braking, or kick sideways over lips and square-
edged terrain. It may even top-out when you
dismount your CRF.
Because of the great absorption quality of the
shock bumper rubber, it may be difficult for you to
notice when your CRF's suspension is bottoming.
Some riders may think the damping or perhaps the
leverage ratio is too harsh. In reality, the problem
is most likely insufficient spring pre-load or a
spring that is too soft. Either situation prevents
utilizing the full travel.
Keep in mind that a properly adjusted suspension
system may bottom slightly every few minutes at
full speed. Adjusting the suspension to avoid this
occasional bottoming may cost more in overall
suspension performance than it is worth.
Rear Suspension Adjustments
A spring that is too stiff for your weight will not
allow the rear tyre to hook up under acceleration
and will pass more bumps on to you.
Adjustments for Competition
133