Yamaha YZ450F Owner's Service Manual page 227

SUSPENSION SETTING (FRONT FORK)
• If any of the following symptoms is experienced with the standard position as the base, make resetting by reference to
the adjustment procedure given in the same chart.
• Before any change, set the rear shock absorber sunken length to the standard figure 90–100 mm (3.5–3.9 in).
Symptom
Jump
Stiff over entire
○
range
Unsmooth move-
ment over entire
○
range
Poor initial move-
ment
Soft over entire
range, bottoming
○
out
Stiff toward stroke
○
end
Soft toward stroke
○
end, bottoming out
Stiff initial move-
○
ment
Low front, tending to
lower front posture
"Obtrusive" front,
tending to upper
front posture
Section
Medi-
Large Small
um
gap gap
gap
Compression damping
Oil amount
○ ○
Spring
Outer tube
Inner tube
Slide metal
○ ○ ○
Piston metal
Under bracket tighten-
ing torque
Rebound damping
○
Oil seal
Compression damping
Oil amount
○
Spring
Oil amount
Oil amount
Compression damping
○ ○ ○
Compression damping
Rebound damping
○ ○
Balance with rear end
Oil amount
Compression damping
Balance with rear end
○ ○
Spring
Oil amount
Check
Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Decrease oil amount by about 5–10 cm
Imp oz, 0.2–0.3 US oz).
Replace with soft spring.
Check for any bends, dents, and other noticeable
scars, etc. If any, replace affected parts.
Replace with a new one for extended use.
Replace with a new one for extended use.
Retighten to specified torque.
Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Apply grease in oil seal wall.
Turn adjuster clockwise (about 2 clicks) to in-
crease damping.
Increase oil amount by about 5–10 cm
Imp oz, 0.2–0.3 US oz).
Replace with stiff spring.
Decrease oil amount by about 5 cm
oz,0.2 US oz).
Increase oil amount by about 5 cm
oz,0.2 US oz).
Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Turn adjuster clockwise (about 2 clicks) to in-
crease damping.
Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Set sunken length for 95–100 mm (3.7–3.9 in)
when one passenger is astride seat (lower rear
posture).
Increase oil amount by about 5 cm
0.2 US oz).
Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Set sunken length for 90–95 mm (3.5–3.7 in)
when one passenger is astride seat (upper rear
posture).
Replace with soft spring.
Decrease oil amount by about 5–10 cm
Imp oz, 0.2–0.3 US oz).
8-4
CHASSIS
Adjust
3
(0.2–0.4
3
(0.2–0.4
3
(0.2 Imp
3
(0.2 Imp
3
(0.2 Imp oz,
3
(0.2–0.4