wheel YAMAHA WR 250F 2015 Workshop Manual

CHAIN DRIVE
5-69
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4. Check:
• O-rings “1”
Damage  Replace the drive chain.
• Drive chain rollers “2”
Damage/wear  Replace the drive chain.
• Drive chain side plates “3”
Damage/wear  Replace the drive chain.
5. Lubricate:
•Drive chain
EAS2GB2224CHECKING THE DRIVE SPROCKET
1. Check:
• Drive sprocket
More than 1/4 tooth wear “a”  Replace the
drive sprocket and the rear wheel sprocket
as a set.
Bent tooth  Replace the drive sprocket
and the rear wheel sprocket as a set.
EAS2GB2225CHECKING THE REAR WHEEL SPROCKET
Refer to “CHECKING AND REPLACING THE
REAR WHEEL SPROCKET” on page 5-10.
EAS2GB2226INSTALLING THE DRIVE CHAIN
1. Install:
•Drive chain
ECA
NOTICE
Be sure to put on safety goggles when
working.
TIP
Install the drive chain joint with the drive chain
cut & rivet tool. (Use goods on the market)
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a. When press fitting the connecting plate “1”,
make sure the space “a” between the end of
the connecting pin “2” and the connecting
plate is 1.2–1.4 mm (0.05–0.06 in).
b. After riveting, make sure the diameter be-
tween the edges “b” of the connecting pin “2”
is 5.5–5.8 mm (0.22–0.23 in). Recommended lubricant
Chain lubricant suitable for O-
ring chains
b. Correct
1. Drive chain roller
2. Drive sprocket

CLUTCH......................................................................................................... 6-40
REMOVING THE CLUTCH ...................................................................... 6-43
CHECKING THE FRICTION PLATES...................................................... 6-43
CHECKING THE CLUTCH PLATES ........................................................ 6-43
CHECKING THE CLUTCH SPRINGS...................................................... 6-43
CHECKING THE CLUTCH HOUSING ..................................................... 6-44
CHECKING THE CLUTCH BOSS ............................................................ 6-44
CHECKING THE PRESSURE PLATE ..................................................... 6-44
CHECKING THE PUSH LEVER SHAFT .................................................. 6-44
CHECKING THE CLUTCH PUSH RODS ................................................ 6-44
CHECKING THE PRIMARY DRIVE GEAR .............................................. 6-44
CHECKING THE PRIMARY DRIVEN GEAR ........................................... 6-45
INSTALLING THE OIL SEAL................................................................... 6-45
INSTALLING THE RIGHT CRANKCASE COVER ................................... 6-45
INSTALLING THE CLUTCH ..................................................................... 6-45
INSTALLING THE KICKSTARTER LEVER ............................................. 6-48
KICKSTATER................................................................................................. 6-49
REMOVING THE KICK SHAFT ASSEMBLY ........................................... 6-50
CHECKING THE KICK SHAFT AND RATCHET WHEEL ........................ 6-50
CHECKING THE KICK GEAR, KICK IDLE GEAR AND RATCHET
WHEEL .................................................................................................... 6-50
INSTALLING THE KICK SHAFT ASSEMBLY .......................................... 6-50
INSTALLING THE KICK IDLE GEAR ....................................................... 6-51
SHIFT SHAFT................................................................................................. 6-52
REMOVING THE SHIFT GUIDE AND SHIFT LEVER ASSEMBLY ......... 6-53
REMOVING THE SEGMENT ................................................................... 6-53
CHECKING THE SHIFT SHAFT .............................................................. 6-53
CHECKING THE SHIFT GUIDE AND SHIFT LEVER ASSEMBLY ......... 6-53
CHECKING THE STOPPER LEVER ....................................................... 6-53
INSTALLING THE STOPPER LEVER ..................................................... 6-54
INSTALLING THE SEGMENT.................................................................. 6-54
INSTALLING THE SHIFT GUIDE AND SHIFT LEVER ASSEMBLY ....... 6-54
INSTALLING THE SHIFT SHAFT ............................................................ 6-55
INSTALLING THE SHIFT PEDAL ............................................................ 6-55
OIL PUMP AND BALANCER GEAR............................................................. 6-56
REMOVING THE BALANCER ................................................................. 6-58
CHECKING THE PRIMARY DRIVE GEAR, BALANCER SHAFT DRIVE
GEAR, AND BALANCER WEIGHT GEAR .............................................. 6-58
CHECKING THE BALANCER .................................................................. 6-58
CHECKING THE OIL PUMP .................................................................... 6-58
ASSEMBLING THE OIL PUMP ................................................................ 6-59
INSTALLING THE OIL PUMP AND BALANCER GEAR .......................... 6-59

ENGINE REMOVAL
6-3
Removing the electronic parts
Order Part name Q’ty Remarks
Use a suitable stand to raise the front wheel
off the ground.
Seat Refer to “GENERAL CHASSIS” on page 5-1.
Side cover (left/right) Refer to “GENERAL CHASSIS” on page 5-1.
Air scoop (left / right) Refer to “GENERAL CHASSIS” on page 5-1.
Fuel tank Refer to “FUEL TANK” on page 8-1.
Air filter case cover
1 Rectifier/regulator 1
2ECU 1
3 Ignition coil 1
4 Neutral switch 1
5 AC magneto coupler 1 Disconnect.
6 Crankshaft position sensor coupler 1 Disconnect.
7 Coolant temperature sensor coupler 1 Disconnect.
For installation, reverse the removal proce-
dure.
T.R.
T.R.
T.R.T.R.
7 3
6
5
142
LT
New
LS

ENGINE REMOVAL
6-4
Removing the engine
Order Part name Q’ty Remarks
Use a suitable stand to raise the front wheel
off the ground.
Seat Refer to “GENERAL CHASSIS” on page 5-1.
Side cover (left/right) Refer to “GENERAL CHASSIS” on page 5-1.
Air scoop (left / right) Refer to “GENERAL CHASSIS” on page 5-1.
Fuel tank Refer to “FUEL TANK” on page 8-1.
Exhaust pipe and silencer Refer to “ENGINE REMOVAL” on page 6-1.
Air filter case Refer to “THROTTLE BODY” on page 8-7.
Throttle body Refer to “THROTTLE BODY” on page 8-7.
Clutch cable Refer to “CLUTCH” on page 6-40.
Shift pedal Refer to “SHIFT SHAFT” on page 6-52.
Starter motor 1Refer to “ELECTRIC STARTER” on page 6-
35.
1 Engine guard 1
2 Brake pedal 1
3Spring 1
New
New
LS
M
8
8
7
6
13
45
New
1 12
3
2
1110
9
55 Nm (5.5 m kgf, 40 ft Ibf)T.R.

KICKSTATER
6-49
EAS2GB2283
KICKSTATER
Removing the kick shaft
Order Part name Q’ty Remarks
Primary driven gear Refer to “CLUTCH” on page 6-40.
1 Kick idle gear 1
2 Kick shaft assembly 1
3 Spring guide 1
4 Torsion spring 1
5 Ratchet wheel 1
6 Kick gear 1
7 Kick shaft 1
For installation, reverse the removal proce-
dure.

KICKSTATER
6-50
EAS2GB2284REMOVING THE KICK SHAFT ASSEMBLY
1. Remove:
• Kick shaft assembly “1”
TIP
Unhook the torsion spring “2” from the hole “a”
in the crankcase.
EAS2GB2285CHECKING THE KICK SHAFT AND RATCH-
ET WHEEL
1. Check:
• Ratchet wheel “1” smooth movement
Unsmooth movement  Replace.
• Kick shaft “2”
Wear/damage  Replace the kick shaft as-
sembly.
• Spring “3”
Broken  Replace.
EAS2GB2286CHECKING THE KICK GEAR, KICK IDLE
GEAR AND RATCHET WHEEL
1. Check:
• Kick gear “1”
Wear/damage  Replace the kick shaft as-
sembly.
• Kick idle gear “2”
• Ratchet wheel “3”
• Gear teeth “a”
• Ratchet teeth “b”
Wear/damage  Replace.
EAS2GB2287INSTALLING THE KICK SHAFT ASSEMBLY
1. Install:
• Kick gear “1”
• Washer “2”
• Circlip “3”
• Ratchet wheel “4”
• Spring “5”
• Washer “6”
• Circlip “7”
(to the kick shaft “8”)
TIP
• Apply molybdenum disulfide oil to 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 the kick shaft “2”)
TIP
Make sure the stopper “a” of the torsion spring
fits into the hole “b” on the kick shaft.
31
2
a
b
3
12
New
New

KICKSTATER
6-51
3. Install:
• Spring guide “1”
TIP
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”
TIP
• Before installation, apply molybdenum disul-
fide grease to the contacting surfaces of the
kick shaft ratchet wheel guide “2” and the kick
shaft stopper “a”.
• Apply the engine oil on the kick shaft.
• Slide the kick shaft assembly into the crank-
case and make sure the kick shaft stopper “a”
fits into the kick shaft ratchet wheel guide.5. Install:
• Torsion spring “1”
TIP
Turn the torsion spring clockwise and hook into
the proper hole “a” in the crankcase.
EAS2GB2288INSTALLING THE KICK IDLE GEAR
1. Install:
• Kick idle gear “1”
• Washer “2”
• Circlip “3”
TIP
• Apply the engine oil on the kick idle gear inner
circumference.
• Install the kick idle gear with its depressed
side “a” toward you.
1 2a b
New

TRANSMISSION
6-79
2. Install:
• 2nd wheel gear (29T) “1”
• 5th wheel gear (22T) “2”
• 3rd wheel gear (26T) “3”
• 4th wheel gear (24T) “4”
• 6th wheel gear (22T) “5”
• Collar “6”
• 1st wheel gear (31T) “7”
• O-ring “8”
(to the drive axle “9”)
TIP
• Before installation, apply molybdenum disul-
fide oil to the inner and end surface of the idler
gear and to the inner surface of the sliding
gear, then install.
• Apply the lithium-soap-based grease on the
O-ring.
3. Install:
• Washer “1”
• Circlip “2”
TIP
• Be sure the circlip sharp-edged corner “a” is
positioned opposite side to the washer and
gear “b”.
• Install the circlip with its ends “c” settled even-
ly on the spline crests.4. Install:
• Collar “1”
TIP
• Apply the lithium-soap-based grease on the
oil seal lip.
• When installing the collar into the crankcase,
pay careful attention to the crankcase oil seal
lip.
5. Install:
• Main axle “1”
• Drive axle “2”
TIP
• Install to the left crankcase simultaneously.
• Apply engine oil to the main axle and the drive
axle bearing.
New
891
234
567M
New
LS
M
New
21
2
ab
cc
1
2
EE

TRANSMISSION
6-80
6. Install:
• Shift fork 1 (L) “1”
• Shift fork 2 (C) “2”
• Shift fork 3 (R) “3”
• Shift cam “4”
(to the main axle and the drive axle)
TIP
• Apply engine oil to the shift fork grooves.
• Apply engine oil to the shift cam groove and
the bearing contact surface.
• Mesh the shift fork 1 (L) with the 5th wheel
gear “5” and “3” (R) with the 6th wheel gear “7”
on the drive axle.
• Mesh the shift fork 2 (C) with the 3rd/4th pin-
ion gear “6” on the main axle.7. Install:
• Long shift fork guide bar “1”
• Short shift fork guide bar “2”
• Spring “3”
TIP
• Screw the spring into the shift fork guide bar
lightly beforehand.
• Apply the engine oil on the shift fork guide
bars.
8. Check:
• Operation of shift cam and shift fork
• Transmission operation
Unsmooth operation  Repair.
3
12
6
2
4
5
3
7
1
E
E
E
2 13
E

ELECTRICAL COMPONENTS
9-77
EAS2GB2397CHECKING THE SPEED SENSOR
1. Check:
• Speed sensor output voltage
Out of specification  Replace.
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a. Connect the test harness-speed sensor (3P)
to the speed sensor coupler and wire har-
ness.
b. Connect the pocket tester (DC20V) to the
test harness-speed sensor (3P).
c. Set the main switch to “ON”.
d. Elevate the front wheel and slowly turn it.
e. Measure the voltage (DC 5 V) of white and
black/white. With the front wheel slowly ro-
tating, voltage alternates between 0 V and 5
V.
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1. Drain the gasoline.
2. Disconnect:
• Fuel sender coupler
(from the fuel sender)
3. Remove:
• Fuel sender
(from the fuel tank)4. Check:
• Fuel sender resistance
Out of specification  Replace the fuel
sender.
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a. Connect the pocket tester ( 1k) to the
fuel sender as shown.
b. Measure the resistance of the fuel sender.
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EAS2GB2399CHECKING THE RESISTER
1. Disconnect:
• Resister coupler
(from the wire harness)
2. Check:
• Resister resistance
Out of specification  Replace the resister.
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a. Connect the pocket tester ( 10) to the re-
sister as shown. Output voltage reading cycle
0.6V to 4.8V to 0.6V to 4.8V
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
Test harness– speed sensor 5TJ
(3P)
90890-03228
Test harness– speed sensor 5TJ
(3P)
YU-03228
• Positive tester probe 
White “1”
• Negative tester probe 
Black “2”
BRW
21
Fuel sender resistance
1.35–1.90 k at 25°C (77°F)
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
• Positive tester probe 
Green “2”
• Negative tester probe 
Black “1”
Resister resistance
64.6–71.4 
Pocket tester
90890-03112
Analog pocket tester
YU-03112-C
1
2