2016 YAMAHA YZ450F Owners Manual

FRONT FORK
4-45
TIP
• Apply the lithium-soap-based grease on the
dust seal lip and oil seal lip.
• Apply the fork oil on the inner tube.
• When installing the oil seal, use vinyl seat “a”
with fork oil applied to protect the oil seal lip.
15.Install:
• Inner tube bushing “1”
TIP
Install the inner tube bushing onto the slot on
inner tube.
16.Install:
• Outer tube “1”
(to the inner tube “2”)17.Install:
• Inner tube bushing “1”
• Washer “2”
(to the outer tube)
TIP
Press the inner tube bushing into the outer tube
with fork seal driver “3”.
18.Install:
• Oil seals “1”
TIP
Using a fork seal driver “2,” press the oil seal in
until the stopper ring groove fully appears.
LS
New
Fork seal driver
90890-01502
YM-A0948
Fork seal driver
90890-01502
YM-A0948
New

FRONT FORK
4-46
19.Install:
• Oil seal clip “1”
TIP
Fit the oil seal clip correctly in the groove in the
outer tube.
20.Install:
• Dust seal “1”
TIP
Apply lithium-soap-based grease on the inner
tube.
21.Check:
• Inner tube smooth movement
Tightness/binding/rough spots  Repeat
the steps 14 to 20.22.Measure:
• Distance “a”
Out of specification  Turn into the locknut.
23.Install:
• Collar “1”
• Fork spring “2”
(to the damper assembly “3”)
TIP
Install the collar with its larger dia. end “a” fac-
ing the fork spring.
New
Distance “a”
16 mm (0.63 in) or more
Between the damper assembly
“1” bottom and locknut “2” bot-
tom.
1 2a
12
3
a

FRONT FORK
4-47
24.Install:
• Damper assembly “1”
(to the inner tube “2”)
ECA32D1010
NOTICE
Allow the damper assembly to slide slowly
down the inner tube until it contacts the bot-
tom of the inner tube. Be careful not to dam-
age the inner tube.
25.Loosen:
• Rebound damping force adjuster “1”
TIP
• Before loosening the damping force adjuster,
record the setting position.
• Unless the damping force adjuster is fully
loosened, correct damping characteristic can-
not be obtained after installation.
26.Install:
• Damper adjusting rod “1”
• Copper washer “2”
• Adjuster “3”
(to the damper assembly “4”)
TIP
• While compressing the inner tube “5”, set the
cap bolt ring wrench “7” between the inner
tube and locknut “6”.
• Fully finger tighten the adjuster onto the
damper assembly.27.Measure:
• Gap “a” between the adjuster “1” and the
locknut “2”
Out of specification  Retighten and read-
just the locknut.
TIP
If it is installed with a gap out of specification,
correct damping force cannot be obtained.
28.Tighten:
• Adjuster (locknut) “1”
TIP
Hold the locknut “2” and tighten the adjuster.
Cap bolt ring wrench
90890-01501
YM-01501
1
2
1
New
Gap “a” between the adjuster and
the locknut
0.5–1.0 mm (0.02–0.04 in)
Adjuster (locknut)
29 Nm (2.9 m·kgf, 21 ft·lbf)
1
2a
T R..

FRONT FORK
4-48
29.Install:
• Adjuster “1”
(to the inner tube)
30.Fill:
• Front fork leg
ECA14210
NOTICE
• Be sure to use the recommended oil. Other
oils may have an adverse effect on front
fork performance.
• When disassembling and assembling the
front fork leg, do not allow any foreign ma-
terial to enter the front fork.31.Install:
• Damper assembly “1”
(to the outer tube)
TIP
Temporarily tighten the damper assembly.
32.Install:
• Protector guide “1”
EASB111169INSTALLING THE FRONT FORK LEGS
1. Install:
• Front fork “1”
TIP
• Temporarily tighten the pinch bolts (lower
bracket).
• Do not tighten the pinch bolts (upper bracket)
yet. Adjuster
55 Nm (5.5 m·kgf, 40 ft·lbf)
LOCTITE®
Recommended oil
Suspension oil S1
Standard oil amount
315 cm
3 (10.65 US oz, 11.11 lmp
oz)
Extent of adjustment
300–365 cm
3 (10.14–12.34 US
oz, 10.58–12.87 lmp oz)
T R..
1LT
1

FRONT FORK
4-49
2. Tighten:
• Damper assembly “1”
TIP
Use the cap bolt ring wrench “2” to tighten the
damper assembly.
3. Adjust:
• Front fork top end “a”
4. Tighten:
• Pinch bolt (upper bracket) “1”
• Pinch bolt (lower bracket) “2”
EWA33DD044
WARNING
Tighten the lower bracket to specified
torque. If torqued too much, it may cause
the front fork to malfunction.
5. Install:
• Protector “1”
• Bolt (protector) “2”
6. Adjust:
• Rebound damping force
TIP
Turn in the damping adjuster “1” finger-tight
and then turn out to the originally set position. Damper assembly
30 Nm (3.0 m·kgf, 22 ft·lbf)
Cap bolt ring wrench
90890-01501
YM-01501
Front fork top end (standard) “a”
0 mm (0 in)
Upper bracket pinch bolts
21 Nm (2.1 m·kgf, 15 ft·lbf)
Lower bracket pinch bolts
21 Nm (2.1 m·kgf, 15 ft·lbf)
T R..
2
1
a
T R..
T R..
Bolt (protector)
5 Nm (0.5 m·kgf, 3.6 ft·lbf)
21
T R..
1
2
1

FRONT FORK
4-50
7. Adjust:
• Compression damping force
TIP
Turn in the damping adjuster “1” finger-tight
and then turn out to the originally set position.
1

STEERING HEAD
4-51
EASB111170
STEERING HEAD
Removing the lower bracket
Order Part name Q’ty Remarks
Refer to “CHECKING AND ADJUSTING
THE STEERING HEAD” on page 3-35.
Use a suitable stand to raise the front wheel
off the ground.
Number plate Refer to “GENERAL CHASSIS” on page 4-1.
Handlebar Refer to “HANDLEBAR” on page 4-32.
1 Front fender 1
2 Steering stem nut 1
3 Front fork leg (s) 2 Refer to “FRONT FORK” on page 4-38.
4 Upper bracket 1
5 Steering ring nut 1
6 Lower bracket 1
7 Bearing race cover 1
8 Upper bearing 1
9 Bearing (lower side) 1
10 Bearing races 2
For installation, reverse the removal proce-
dure.
2
4
5
7
3
1
6
8
9
10
LS
T
.R.
LS
LS
T
.R.21 Nm (2.1 mlbf) kgf, 15 ft
T
.R.9 Nm (0.9 mlbf) kgf, 6.5 ft
T
.R.21 Nm (2.1 mlbf) kgf, 15 ft
T
.R.10 Nm (1.0 mlbf) kgf, 7.2 ft
T
.R.145 Nm (14.5 mlbf) kgf, 105 ft
38 Nm (3.8 m
lbf) kgf, 27 ft
7 Nm (0.7 m
lbf) kgf, 5.1 ft
*
*

STEERING HEAD
4-52
EASB111171REMOVING THE LOWER BRACKET
1. Use a suitable stand to raise the front wheel
off the ground.
EWA
WARNING
Securely support the vehicle so that there is
no danger of it falling over.
2. Remove:
• Rng nut “1”
TIP
Remove the ring nut with the steering nut
wrench “2”.
EWA
WARNING
Securely support the lower bracket so that
there is no danger of it falling.
EASB111172CHECKING THE STEERING HEAD
1. Wash with kerosene:
• Bearing
• Bearing races
2. Check:
• Bearing
• Bearing races
Damage/pitting  Replace.
3. Replace:
• Bearing
• Bearing races
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Remove the bearing race from the steering
head pipe with a long rod “1” and a hammer.
b. Remove the bearing race from the lower
bracket with a chisel “2” and a hammer.
c. Install a new bearing race.
ECA
NOTICE
If the bearing race is not installed properly,
the steering head pipe could be damaged.
TIP
Always replace the bearing and the bearing
race as a set.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
4. Check:
• Upper bracket
• Lower bracket
(along with the steering stem)
Bends/cracks/damage  Replace.
EASB111173INSTALLING THE STEERING HEAD
1. Install:
• Lower bearing “1”
TIP
Apply the lithium-soap-based grease on the
dust seal lip and bearing inner circumference. Steering nut wrench
90890-01403
Exhaust flange nut wrench
YU-A9472