2016 YAMAHA WR 450F Owners Manual

ELECTRIC STARTER
6-38
EAS2GC1263CHECKING THE STARTER MOTOR
1. Check:•CommutatorDirt  Clean with 600 grit sandpaper.
2. Measure: • Commutator diameter “a”Out of specification  Replace the starter
motor.
3. Measure: • Mica undercut “a”Out of specification  Scrape the mica to
the proper measurement with a hacksaw
blade that has been grounded to fit the com-
mutator.
TIP
The mica of the commutator must be undercut
to ensure proper operation of the commutator.
4. Measure: • Armature assembly resistances (commuta-
tor and insulation)
Out of specification  Replace the starter
motor.
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Measure the armature assembly resistanc-
es with the pocket tester.
b. If any resistance is out of specification, re- place the starter motor.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
5. Measure:• Brush length “a”Out of specification  Replace the brush
set.
6. Measure: • Brush spring force
Out of specification  Replace the brush
set.
Limit
16.6 mm (0.65 in)
Mica undercut (depth) 1.50 mm (0.06 in)
Pocket tester90890-03112
Analog pocket tester YU-03112-C
Armature coil Commutator resistance “1” 0.0117–0.0143 
Insulation resistance “2” Above 1 M 
Limit 3.50 mm (0.14 in)
Brush spring force 3.92–5.88 N (400–600 gf, 14.11–
21.17 oz)

ELECTRIC STARTER
6-39
7. Check:• Gear teethDamage/wear  Replace the starter motor.
8. Check: • Oil sealDamage/wear  Replace the defective part
(s).
EAS2GC1264ASSEMBLING THE STARTER MOTOR
1. Install: • Brush spring “1”
• Brush “2”
TIP
Align the corner of brush terminal “a” with
groove “b” and fit them together.
2. Install:• Armature assembly “1”
Install while holding down the brush using a
thin screw driver.
ECA
NOTICE
Be careful not to damage the brush during
installation.
3. Install:• O-ring “1”
• Starter motor yoke “2”
TIP
• Install the starter motor yoke with its groove “a” facing starter motor rear cover.
• Align the match mark “b” on the starter motor
yoke with the match mark “c” on the starter
motor rear cover. 4. Install:
• Circlip “1”
•Plain washer “2”
• O-ring “3”
• Washer (starter motor front cover) “4”
• Starter motor front cover “5”
TIP
• For installation, align the projections on the
washer with the slots in the front cover.
• Align the match mark “a” on the starter motor yoke with the match mark “b” on the starter
motor front cover.
5. Install: •Bolt “1”
• O-ring “2”
TIP
Apply the lithium-soap-based grease on the O-
ring.
a
b1
1
2
2
New
c b
a
1 2
New
a
12
3
b
45
New
2
1 1

ELECTRIC STARTER
6-40
6. Install:• Starter motor “1”
• Starter motor cover “2”
• Starter motor bolt “3”
• Starter motor cover bolt “4”
TIP
Pass the AC magneto lead “5” and the starter
motor laed “6” under the left crankcase cover
“a” as shown. Starter motor bolt
12 Nm (1.2 m·kgf, 8.7 ft·lbf)
Starter motor cover bolt 12 Nm (1.2 m·kgf, 8.7 ft·lbf)
T R..
15
6
4
3
2
a

CLUTCH
6-41
EAS2GC1265
CLUTCH
Removing the clutch
OrderPart name Q’tyRemarks
Engine oil Drain.
Refer to “CHANGING THE ENGINE OIL” on
page 3-17.
Brake pedal Refer to “ENGINE REMOVAL” on page 6-1.
1 Clutch cable 1 Disconnect.
2 Clutch cover 1
3 O-ring 1
4 Clutch spring 6
5 Pressure plate 1
6 Push rod 1 1
7 Circlip 1
8Washer 1
9 Bearing 1
10 Ball 1
11 Push rod 2 1
12 Friction plate 1 3
13 Clutch plate 1 4 Thickness:2.0 mm (0.079 in)
LS
New
New
New
2
3
4
5
78 9
610 11
12
12
20
1
14
16
13
15 19
18
17
T.R.
T.R.
T.R.
T.R.
LT
(2) (5) (6)

CLUTCH
6-42
14 Friction plate 25 Identification color (purple)
15 Clutch plate 2 3 Thickness:1.6 mm (0.063 in)
16 Cushion spring 1
17 Clutch boss 1
18 Thrust washer 1
19 Primary driven gear 1
20 Push lever shaft 1
For installation, reverse the removal proce-
dure.
Removing the clutch
Order Part name Q’tyRemarks
LS
New
New
New
2
3
4
5
78 9
610 11
12
12
20
1
14
16
13
15 19
18
17
T.R.
T.R.
T.R.
T.R.
LT
(2) (5) (6)

CLUTCH
6-43
Removing the right crankcase cover
OrderPart name Q’tyRemarks
Engine guard Refer to “ENGINE REMOVAL” on page 6-1.
Engine oil Drain.
Refer to “CHANGING THE ENGINE OIL” on
page 3-17.
Coolant Drain.
Refer to “CHANGING THE COOLANT” on
page 3-10.
Brake pedal Refer to “ENGINE REMOVAL” on page 6-1.
Clutch cover Refer to “CLUTCH” on page 6-41.
1 Oil filter element cover 1
2 Oil filter element 1
3 Radiator pipe 2 1
4 Kickstarter lever 1
5 Right crankcase cover 1
6 Gaskets 1
7 Dowel pin 2
8Collar 1
For installation, reverse the removal proce-
dure.
T.R.
LS
New
New
67
2
5
4
1
7
8
New
3
LS
New
New
LS
LS
NewNew
LT
LS

CLUTCH
6-44
EAS2GC1266REMOVING THE CLUTCH
1. Remove:• Clutch boss nut “1”
• Conical washer “2”
• Clutch boss “3”
TIP
While holding the clutch boss with the clutch
holder “4”, loosen the clutch boss nut.
EAS2GC1267CHECKING THE FRICTION PLATES
1. Check:• Friction plate
Damage/wear  Replace the friction plates
as a set.
2. Measure:
• Friction plate thicknessOut of specification  Replace the friction
plates as a set.
TIP
Measure it at four points on the friction plate.
EAS2GC1268
CHECKING THE CLUTCH PLATES
1. Check: • Clutch plate
Damage  Replace the clutch plates as a
set.
2. Measure:
• Clutch plate warpage(with a surface plate and thickness gauge
“1”)
Out of specification  Replace the clutch
plates as a set.
EAS2GC1269CHECKING THE CLUTCH SPRINGS
1. Check: • Clutch springDamage  Replace the clutch springs as a
set.
2. Measure: • Clutch spring free lengthOut of specification  Replace the clutch
springs as a set.
Universal clutch holder
90890-04086
Universal clutch holder YM-91042
Friction plate thickness 2.92–3.08 mm (0.115–0.121 in)
Wear limit 2.85 mm (0.112 in)
3 4
12
Warpage limit
0.10 mm (0.004 in)
Clutch spring free length 50.00 mm (1.97 in)
Limit 47.50 mm (1.87 in)

CLUTCH
6-45
EAS2GC1270CHECKING THE CLUTCH HOUSING
1. Check:• Clutch housing dogs “a”Damage/pitting/wear  Deburr the clutch
housing dogs or replace the clutch housing.
TIP
Pitting on the clutch ho using dogs will cause er-
ratic clutch operation.
EAS2GC1271CHECKING THE CLUTCH BOSS
1. Check:
• Clutch boss splines
Damage/pitting/wear  Replace the clutch
boss.
TIP
Pitting on the clutch boss splines will cause er-
ratic clutch operation.
EAS2GC1272CHECKING THE PRESSURE PLATE
1. Check: • Pressure plateCrack/damage  Replace.
EAS2GC1273CHECKING THE PUSH LEVER SHAFT
1. Check:
• Push lever shaftWear/damage  Replace.
EAS2GC1274CHECKING THE CLUTCH PUSH RODS
1. Check:
• Push rod 1 “1”
• Bearing “2”
• Washer “3”
• Push rod 2 “4”
•Ball “5”
Cracks/damage/wear  Replace.
2. Measure: • Push rod 2 bending limit
Out of specification  Replace.
EAS2GC1275CHECKING THE PRIMARY DRIVE GEAR
1. Check:
• Primary drive gearDamage/wear  Replace the primary drive
and primary driven gears as a set.
Excessive noise during operation  Re-
place the primary drive and primary driven
gears as a set.
2. Check: • Primary-drive-gear-to-primary-driven-gear free play
Free play exists  Replace the primary
drive and primary driven gears as a set.
a
Push rod bending limit 0.10 mm (0.004 in)