2008 YAMAHA WR 450F oil

5-41
OIL PUMP
15 Oil pump drive shaft 1
16 Rotor housing 1 Order Part name Q'ty Remarks

5-42
OIL PUMP
CHECKING THE OIL PUMP
1. Inspect:
• Oil pump drive gear
• Oil pump drive shaft
• Rotor housing
• Oil pump cover
Cracks/wear/damage→Replace.
2. Measure:
• Tip clearance "a"
(between the inner rotor "1" and
outer rotor "2")
• Side clearance "b"
(between the outer rotor "2" and
rotor housing "3")
• Housing and rotor clearance "c"
(between the rotor housing "3"
and rotors "1" "2")
Out of specification→Replace the
oil pump assembly.
3. Check:
•Unsmooth→Repeat steps #1 and
#2 or replace the defective parts.INSTALLING THE OIL PUMP
1. Install:
• Oil pump drive shaft "1"
• Washer "2"
• Dowel pin "3"
• Inner rotor 1 "4"
• Apply the engine oil on the oil pump
drive shaft and inner rotor 1.
• Fit the dowel pin into the groove in
the inner rotor 1.
2. Install:
• Outer rotor 1 "1"
Apply the engine oil on the outer rotor
1.
3. Install:
• Oil pump cover "1"
• Screw (oil pump cover) "2"
• Dowel pin "3"
• Inner rotor 2 "4"
• Circlip "5"
• Apply the engine oil on the oil pump
drive shaft end and inner rotor 2.
• Fit the dowel pin into the groove in
the inner rotor 2.
4. Install:
• Outer rotor 2 "1"
• Dowel pin "2"
• Oil pump assembly "3"
• Bolt (oil pump assembly) "4"
Apply the engine oil on the outer rotor
2.
5. Install:
• Oil pump drive gear "1"
• Washer "2"
• Circlip"3"
Apply the engine oil on the oil pump
drive gear inner circumference.
Tip clearance "a":
0.12 mm or less (0.0047
in or less)
: 0.20 mm
(0.008 in)
Side clearance "b":
0.09–0.17 mm (0.0035–
0.0067 in)
: 0.24 mm
(0.009 in)
Housing and rotor clear-
ance "c":
0.03–0.10 mm (0.0012–
0.0039 in)
: 0.17 mm
(0.0067 in)
Screw (oil pump cover):
2 Nm (0.2 m•kg, 1.4
ft•lb)
Bolt (oil pump assem-
bly):
10 Nm (1.0 m•kg, 7.2
ft•lb)

5-43
KICK SHAFT AND SHIFT SHAFT
KICK SHAFT AND SHIFT SHAFT
REMOVING THE KICK SHAFT AND SHIFT SHAFT
Order Part name Q'ty Remarks
Oil pump Refer to "OIL PUMP" section.
1 Kick idle gear 1
2 Kick shaft assembly 1 Refer to removal section.
3 Spring guide 1
4 Torsion spring 1
5 Ratchet wheel 1
6 Kick gear 1
7 Kick shaft 1
8 Washer 1
9 Shift pedal 1
10 Shift shaft 1
11 Collar 1
12 Torsion spring 1
13 Roller 1
14 Shift guide 1 Refer to removal section.
15 Shift lever assembly 1 Refer to removal section.
16 Shift lever 1

5-46
KICK SHAFT AND SHIFT SHAFT
INSTALLING THE SHIFT GUIDE
AND SHIFT LEVER ASSEMBLY
1. Install:
• Spring "1"
• Pawl pin "2"
•Pawl "3"
To shift lever "4".
Apply the engine oil on the spring,
pawl pin and pawl.
2. Install:
• Shift lever assembly "1"
To shift guide "2".
3. Install:
• Shift lever assembly "1"
• Shift guide "2"
• The shift lever assembly is installed
at the same time as the shift guide.
• Apply the engine oil on the bolt
(segment) shaft.
4. Install:
• Bolt (shift guide) "1" INSTALLING THE SHIFT SHAFT
1. Install:
• Roller "1"
• Collar "2"
• Torsion spring "3"
• Washer "4"
• Shift shaft "5"
Apply the engine oil on the roller and
shift shaft.
2. Install:
• Shift pedal
Refer to "AC MAGNETO AND
STARTER CLUTCH" section.
INSTALLING THE KICK SHAFT
ASSEMBLY
1. Install:
• Kick gear "1"
• Washer "2"
• Circlip "3"
• Ratchet wheel "4"
• Spring "5"
• Washer "6"
• Circlip "7"
To kick shaft "8".
• Apply the molybdenum disulfide oil
on the inner circumferences of the
kick gear and ratchet wheel.
• Align the punch mark "a" on the
ratchet wheel with the punch mark
"b" on the kick shaft.
2. Install:
• Torsion spring "1"
To kick shaft "2".
Make sure the stopper "a" of the tor-
sion spring fits into the hole "b" on the
kick shaft.
3. Install:
• Spring guide "1"
Slide the spring guide into the kick
shaft, make sure the groove "a" in the
spring guide fits on the stopper of the
torsion spring.
4. Install:
• Kick shaft assembly "1"
• Washer "2"
• Apply the molybdenum disulfide
grease on the contacting surfaces
of the kick shaft stopper "a" and kick
shaft ratchet wheel guide "3".
• Apply the engine oil on the kick
shaft.
• Slide the kick shaft assembly into
the crankcase and make sure the
kick shaft stopper "a" fits into the
kick shaft ratchet wheel guide.
5. Hook:
• Torsion spring "1"
Turn the torsion spring clockwise and
hook into the proper hole "a" in the
crankcase.Bolt (shift guide):
10 Nm (1.0 m•kg, 7.2
ft•lb)

5-47
KICK SHAFT AND SHIFT SHAFT
INSTALLING THE KICK IDLE
GEAR
1. Install:
• Kick idle gear "1"
• Washer "2"
• Circlip "3"
• Apply the engine oil on the kick idle
gear inner circumference.
• Install the kick idle gear with its de-
pressed side "a" toward you.

5-48
AC MAGNETO AND STARTER CLUTCH
AC MAGNETO AND STARTER CLUTCH
REMOVING THE AC MAGNETO AND STARTER CLUTCH
Order Part name Q'ty Remarks
Drain the engine oil.Refer to "CHANGING THE ENGINE OIL"
section in the CHAPTER 3.
Seat and fuel tankRefer to "REMOVING THE SEAT, FUEL
TANK AND SIDE COVERS" section in the
CHAPTER 3.
Disconnect the AC magneto lead.
1 Shift pedal 1
2 Cover (torque limiter) 1
3 Torque limiter 1 Do not disassemble.
4 Crankcase cover (left) 1
5 Gasket 1
6 Dowel pin 2
7 Idle gear 1
8 Bearing 1
9Shaft 1
10* Nut (rotor) 1 Refer to NOTE.
11 Rotor 1 Refer to removal section.

5-49
AC MAGNETO AND STARTER CLUTCH
Tighten the rotor nut to 65 Nm (6.5 m•kg, 47 ft•lb), loosen and retighten the rotor nut to 65 Nm (6.5 m•kg, 47 ft•lb).
12 Woodruff key 1
13 Starter clutch assembly cover 1 Refer to removal section.
14 Starter clutch 1 Refer to removal section.
15 Starter clutch drive gear 1
16 Holder 1
17 Pickup coil 1
18 Stator 1 Order Part name Q'ty Remarks

5-50
AC MAGNETO AND STARTER CLUTCH
REMOVING THE ROTOR
1. Remove:
• Nut (rotor) "1"
• Washer
Use the sheave holder "2".
2. Remove:
• Rotor "1"
Use the rotor puller "2".
REMOVING THE STARTER
CLUTCH
1. Remove:
• Starter clutch assembly cover "1"
Insert a thin screwdriver or the like
under the convexity "a" and remove
the starter clutch assembly cover by
prying it gently to void damage to the
cover.
2. Remove:
• Starter clutch "1"
Using a thin screwdriver or the like,
remove the plate "a" while prying it
upward little by little.
CHECKING THE AC MAGNETO
1. Inspect:
• Rotor inner surface "a"
• Stator outer surface "b"
Damage→Inspect the crankshaft
runout and crankshaft bearing.
If necessary, replace AC magneto
and/or stator.
CHECKING THE WOODRUFF KEY
1. Inspect:
• Woodruff key "1"
Damage→Replace.
CHECKING THE STARTER
CLUTCH
1. Check:
• Starter clutch
Damage/wear→Replace.
2. Check:
• Idle gear
• Idle gear shaft
• Starter clutch drive gear
Pitting/burrs/chips/roughness/
wear→Replace the defective
parts.
3. Check:
• Starter clutch operation
a. Install the starter clutch drive gear
"1" onto the starter clutch "2" and
hold the starter clutch.b. When turning the starter clutch
drive gear counterclockwise "B",
the starter clutch and the starter
clutch drive gear should engage.
If the starter clutch drive gear and
starter clutch do not engage, the
starter clutch is faulty and must be
replaced.
c. When turning the starter clutch
drive gear clockwise "A", it should
turn freely. If the starter clutch
drive gear does not turn freely, the
starter clutch is faulty and must be
replaced.
CHECKING THE TORQUE LIMITER
1. Check:
• Torque limiter
Damage/wear→Replace.
INSTALLING THE AC MAGNETO
AND STARTER CLUTCH
1. Install:
• Stator "1"
• Bolt (stator) "2"
• Pickup coil "3"
• Holder "4"
• Bolt (pickup coil) "5" Sheave holder:
YS-1880-A/90890-
01701
Rotor puller:
YM-04142/90890-04142
Bolt (stator):
7 Nm (0.7 m•kg, 5.1
ft•lb)
Bolt (pickup coil):
10 Nm (1.0 m•kg, 7.2
ft•lb)