Yamaha YZ450FX 2019, Owner'S Service Manual

Page: 379 / 388

CHASSIS
10-6
EAM30179
SUSPENSION SETTING (FRONT FORK)
TIP
• 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
Section
Check Adjust
Jump
Large
gap
Medium
gap
Small
gap
Stiff over entire
range
  
Compression
damping force
Turn adjuster counterclockwise
(about 2 clicks) to decrease
damping.
Oil amount
Decrease oil amount by about 5–
10 cm³ (0.2–0.3 US oz, 0.2–0.4
Imp.oz).
Spring Replace with soft spring.
Unsmooth move-
ment over entire
range
   
Outer tube
Inner tube
Check for any bends, dents, other
noticeable scars, etc. If any,
replace affected parts.
Slide metal
Replace with a new one for
extended use.
Piston metal
Replace with a new one for
extended use.
Lower bracket
tightening torque Retighten to specified torque.
Poor initial move-
ment

Rebound damp-
ing force
Turn adjuster counterclockwise
(about 2 clicks) to decrease
damping.
Oil seals Apply grease in oil seal wall.
Soft over entire
range, bottoming
out
 
Compression
damping force
Turn adjuster clockwise (about 2
clicks) to increase damping.
Oil amount
Increase oil amount by about 5–
10 cm³ (0.2–0.3 US oz, 0.2–0.4
Imp.oz).
Spring Replace with stiff spring.
Stiff toward
stroke end

Oil amount
Decrease oil amount by about 5
cm³ (0.2 US oz, 0.2 Imp.oz).
Soft toward
stroke end, bot-
toming out

Oil amount
Increase oil amount by about 5
cm³ (0.2 US oz, 0.2 Imp.oz).
Stiff initial move-
ment
   
Compression
damping force
Turn adjuster counterclockwise
(about 2 clicks) to decrease
damping.