Rear Suspension - Honda CRF450R Owner's Manual

6. SUSPENSION ADJUSTMENT
After setting the spring preload to obtain the proper
Race Sag, the suspension should sag 0.39 to 0.98 in (10
to 25 mm) from the weight of the sprung portion of the
bike alone.
If after setting the spring preload (Race Sag) the bike
sags more than 0.98 in (25 mm) in the rear under just
its own weight, the spring is too stiff for your weight. In
this case, the spring is not compressed enough, when
the proper Race Sag can be attained, to allow the sus-
pension to extend far enough on its own.
A spring that's too soft for your weight requires so much
preload to achieve the proper Race Sag that it makes
the rear end top-out when the rider dismounts.
If the spring rate is too soft, you have to put a lot of
preload on the spring to keep the desired ride height,
or Race Sag. As a result, the weight transfer is incor-
rect and the rear end tops-out under even light braking
and on downhills.
Many people think that these soft or stiff spring indica-
tions mean the opposite. But when you take into ac-
count the effect of spring preload adjustments and the
necessity of the correct Race Sag dimension, it is easier
to understand.
A spring that's too firm does not allow the rear tire to
hook up under acceleration and passes more of the
bumps on to the rider.
Both lighter and heavier than standard springs are avail-
able for the shock and fork from your authorized Honda
dealer. The need for a stiffer or softer than standard
shock spring may require the installation of optional
rate fork springs as well in order to maintain proper
front/rear suspension balance. These and other com-
ponents are listed in the Optional Parts section of this
manual.
Keep in mind that a properly adjusted suspension sys-
tem may bottom very slightly at least once per lap at
full racing speed. This knowledge, combined with these
adjustment guidelines and those on damping adjust-
ment provided elsewhere in this manual, will give you
a suspension system that's adjusted as well as any fac-
tory rider's motocrosser.
72

REAR SUSPENSION

Shock Adjustment
The rear shock should be adjusted for the rider's weight
and track conditions.
NOTE:
• If your CRF is new, put enough part-throttle break-
in time (about one hour) on it to ensure that the sus-
pension has worked in.
1. Place a workstand under the engine to raise the rear
wheel off the ground.
2. Loosen the connecting tube clamp screw and re-
move the rear subframe's three mounting bolts, then
remove the subframe. See page 19.
3. Check that the spring preload is adjusted to the stan-
dard length. Adjust as necessary by loosening the
lock nut and turning the adjusting nut. Pin spanners
should be used for turning the lock nut and adjust-
ing nut. See page 10 for optional pin spanners.
Spring preload length (Standard spring)
Standard: 10.21 in (259.4 mm)
Min.: 9.80 in (249.0 mm)
Spring preload length (Optional spring)
Min. (Softer. 5.3 kgf/mm): 9.88 in (251 mm)
Min. (Stiffer. 5.7 kgf/mm): 9.88 in (251 mm)
Min. (Stiffer. 5.9 kgf/mm): 9.84 in (250 mm)
NOTE:
• Each complete turn of the adjusting nut changes the
spring length by 1/16 in (1.5 mm).
(1) ADJUSTING NUT (3) PIN SPANNERS
(2) LOCK NUT (4) SPRING LENGTH