Yamaha YZ450F(X), Owner'S Service Manual

Page: 62 / 574

3-18
CHASSIS
ADJUSTING THE REAR SHOCK
ABSORBER SPRING PRELOAD
1. Elevate the rear wheel by placing
the suitable stand under the en-
gine.
2. Remove:
• Rear frame
3. Loosen:
• Locknut "1"
4. Adjust:
• Spring preload
By turning the adjuster "2".
• Be sure to remove all dirt and mud
from around the locknut and adjust-
er before adjustment.
• The length of the spring (installed)
changes 1.5 mm (0.06 in) per turn
of the adjuster.
• The I.D. mark "b" is marked at the
end of the spring.
• The standard length and extent of
adjustment vary according to the
quantity of I.D. marks.
Never attempt to turn the adjuster
beyond the maximum or minimum
setting.
5. Tighten:
• Locknut
6. Install:
• Rear frame (upper)
• Rear frame (lower)
ADJUSTING THE REAR SHOCK
ABSORBER REBOUND DAMPING
FORCE
1. Adjust:
• Rebound damping force
By turning the adjuster "1".
• STANDARD POSITION:
This is the position which is back
by the specific number of clicks
from the fully turned-in position.
(Which align the punch mark "a"
on the adjuster with the punch
mark "b" on the bracket.)
Do not force the adjuster past the
minimum or maximum extent of
adjustment. The adjuster may be
damaged.
ADJUSTING THE REAR SHOCK
ABSORBER LOW COMPRESSION
DAMPING FORCE
1. Adjust:
• Low compression damping force
By turning the adjuster "1".
Stiffer
→
Increase the spring pre-
load. (Turn the adjuster "2" in.)
Softer
→
Decrease the spring pre-
load. (Turn the adjuster "2"
out.)
Spring length (installed)
"a":
Standard
length
Extent of ad-
justment
One I.D. mark
267 mm
(10.51 in)
*262 mm
(10.31 in)
Two I.D. marks
273 mm
(10.75 in)
*268 mm
(10.55 in)
Three I.D.
marks
264.5 mm
(10.41 in)
*259.5 mm
(10.22 in)
255.5–273.5
mm (10.06–
10.77 in)
261.5–279.5
mm (10.30–
11.00 in)
253.0–271.0
mm (9.96–10.67
in)
* For EUROPE
Rear frame (upper):
38 Nm (3.8 m•kg, 27
ft•lb)
Rear frame (lower):
32 Nm (3.2 m•kg, 23
ft•lb)
Stiffer "a"
→
Increase the re-
bound damping force. (Turn
the adjuster "1" in.)
Softer "b"
→
Decrease the re-
bound damping force. (Turn
the adjuster "1" out.)
Extent of adjustment:
Maximum Minimum
Fully turned in
position
20 clicks out
(from maximum
position)
Standard position:
About 12 clicks out
* About 6 clicks out
* For EUROPE
Stiffer "a"
→
Increase the low
compression damping force.
(Turn the adjuster "1" in.)
Softer "b"
→
Decrease the low
compression damping force.
(Turn the adjuster "1" out.)
Extent of adjustment:
Maximum Minimum
Fully turned in
position
20 clicks out
(from maximum
position)