2016 YAMAHA WR 250F Owners Manual

ELECTRIC STARTER
6-36
Disassembling the starter motor
Order Job/Parts to remove Q’ty Remarks
1 Starter motor front cover 1
2 Starter motor yoke 1
3 Armature assembly 1
4 Starter motor rear cover 1
5 Brush set 2
For assembly, reverse the disassembly pro-
cedure.

ELECTRIC STARTER
6-37
EAS2GB7263CHECKING THE STARTER MOTOR
1. Check:
•Commutator
Dirt  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 tester
90890-03112
Analog pocket tester
YU-03112-C
Armature coil
Commutator resistance “1”
0.0189–0.0231 
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
6-38
7. Check:
• Gear teeth
Damage/wear  Replace the starter motor.
8. Check:
• Oil seal
Damage/wear  Replace the defective part
(s).
EAS2GB7264ASSEMBLING THE STARTER MOTOR
1. Install:
• Brush spring “1”
• Brush “2”
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”
ECA
NOTICE
Install the part that has a smaller step differ-
ence “a” with the magnet of the starter mo-
tor yoke facing the starter motor front
cover.
TIP
Align the match mark “a” on the starter motor
yoke with the match mark “b” on the starter mo-
tor rear cover.
4. Install:
• Circlip
•Plain washer “1”
• O-ring “2”
• Washer (starter motor front cover) “3”
• Starter motor front cover “4”
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.
New
ab
New

ELECTRIC STARTER
6-39
5. Install:
•Bolt “1”
• O-ring “2”
TIP
Apply the lithium-soap-based grease on the O-
ring.
New

CLUTCH
6-40
EAS2GB7265
CLUTCH
Removing the clutch
Order Part name Q’ty Remarks
Engine oilDrain.
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
3Gasket 1
4 Clutch spring 5
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 4
13 Clutch plate 8
New
New
New
2
3 45
(5)
(6)78961011
12
22
1
15
12
13
13
18
1920 17
16
14
13
T.R.
T.R.
T.R.
T.R.
LT
21

CLUTCH
6-41
14 Cushion spring 1
15 Friction plate 2 5 Identification color (purple)
16 Clutch boss 1
17 Thrust washer 1
18 Primary driven gear 1
19 Spacer 1
20 Bearing 1
21 Washer 1
22 Push lever shaft 1
For installation, reverse the removal proce-
dure.
Removing the clutch
Order Part name Q’ty Remarks
New
New
New
2
3 45
(5)
(6)78961011
12
22
1
15
12
13
13
18
1920 17
16
14
13
T.R.
T.R.
T.R.
T.R.
LT
21

CLUTCH
6-42
Removing the right crankcase cover
Order Part name Q’ty Remarks
Engine guard Refer to “ENGINE REMOVAL” on page 6-1.
Engine oilDrain.
Refer to “CHANGING THE ENGINE OIL” on
page 3-17.
CoolantDrain.
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 6-40.
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
NewNew
LT
LS

CLUTCH
6-43
EAS2GB7266REMOVING THE CLUTCH
1. Remove:
• Clutch boss nut “1”
• Lock washer “2”
• Clutch boss “3”
TIP
• Straighten the lock washer tab.
• While holding the clutch boss with the clutch
holder “4”, loosen the clutch boss nut.
EAS2GB7267CHECKING THE FRICTION PLATES
1. Check:
• Friction plate
Damage/wear  Replace the friction plates
as a set.
2. Measure:
• Friction plate thickness
Out of specification  Replace the friction
plates as a set.
TIP
Measure it at four points on the friction plate.
EAS2GB7268CHECKING 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.
EAS2GB7269CHECKING THE CLUTCH SPRINGS
1. Check:
• Clutch spring
Damage  Replace the clutch springs as a
set.
2. Measure:
• Clutch spring free length
Out of specification  Replace the clutch
springs as a set. Universal clutch holder
90890-04086
Universal clutch holder
YM-91042
Friction plate thickness
2.90–3.10 mm (0.114–0.122 in)
Wear limit
2.85 mm (0.112 in)
34
12
Warpage limit
0.10 mm (0.004 in)
Clutch spring free length
47.80 mm (1.88 in)
Limit
46.80 mm (1.84 in)