wheel YAMAHA WR 250F 2017 Workshop Manual

CHAIN DRIVE
5-69
EAS23420REMOVING THE DRIVE CHAIN
1. Stand the vehicle on a level surface.
EWA
WARNING
Securely support the vehicle so that there is
no danger of it falling over.
TIP
Place the vehicle on a suitable stand so that the
rear wheel is elevated.
2. Remove:
•Drive chain
TIP
Cut the drive chain with the drive chain cut &
rivet tool. (Use goods on the market)
EAS23441CHECKING THE DRIVE CHAIN
1. Measure:
• 15-link section of the drive chain
Out of specification  Replace the drive
chain.
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a. Measure the length “a” between the inner
sides of the pins and the length “b” between
the outer sides of the pins on a 15-link sec-
tion of the drive chain as shown in the illus-
tration.
b. Calculate the length “c” of the 15-link section
of the drive chain using the following formu-
la.
Drive chain 15-link section length “c” =
(length “a” between pin inner sides + length
“b” between pin outer sides)/2
TIP
• When measuring a 15-link section of the drive
chain, make sure that the drive chain is taut.
• Perform this procedure 2–3 times, at a differ-
ent location each time.
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2. Check:
•Drive chain
Stiffness  Clean, lubricate, or replace.
3. Clean:
•Drive chain
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a. Wipe the drive chain with a clean cloth.
b. Put the drive chain in kerosene and remove
any remaining dirt.
c. Remove the drive chain from the kerosene
and completely dry it. 15-link length limit
239.3 mm (9.42 in)

CHAIN DRIVE
5-70
ECA
NOTICE
• This vehicle has a drive chain with small
rubber O-rings “1” between the drive
chain side plates. Never use high-pressure
water or air, steam, gasoline, certain sol-
vents (e.g., benzine), or a coarse brush to
clean the drive chain. High-pressure meth-
ods could force dirt or water into the drive
chain’s internals, and solvents will deteri-
orate the O-rings. A coarse brush can also
damage the O-rings. Therefore, use only
kerosene to clean the drive chain.
• Do not soak the drive chain in kerosene for
more than ten minutes, otherwise the O-
rings can be damaged.
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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
EAS2GBB222CHECKING 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.
EAS2GBB223CHECKING THE REAR WHEEL SPROCKET
Refer to “CHECKING AND REPLACING THE
REAR WHEEL SPROCKET” on page 5-10.
EAS2GBB224INSTALLING 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)
Recommended lubricant
Chain lubricant suitable for O-
ring chains
b. Correct
1. Drive chain roller
2. Drive sprocket

CLUTCH......................................................................................................... 6-42
REMOVING THE CLUTCH ...................................................................... 6-45
CHECKING THE FRICTION PLATES...................................................... 6-45
CHECKING THE CLUTCH PLATES ........................................................ 6-45
CHECKING THE CLUTCH SPRINGS...................................................... 6-45
CHECKING THE CLUTCH HOUSING ..................................................... 6-46
CHECKING THE CLUTCH BOSS ............................................................ 6-46
CHECKING THE PRESSURE PLATE ..................................................... 6-46
CHECKING THE PUSH LEVER SHAFT .................................................. 6-46
CHECKING THE CLUTCH PUSH RODS ................................................ 6-46
CHECKING THE PRIMARY DRIVE GEAR .............................................. 6-46
CHECKING THE PRIMARY DRIVEN GEAR ........................................... 6-47
INSTALLING THE OIL SEAL................................................................... 6-47
INSTALLING THE RIGHT CRANKCASE COVER ................................... 6-47
INSTALLING THE CLUTCH ..................................................................... 6-47
INSTALLING THE KICKSTARTER LEVER ............................................. 6-50
KICKSTATER................................................................................................. 6-51
REMOVING THE KICK SHAFT ASSEMBLY ........................................... 6-52
CHECKING THE KICK SHAFT AND RATCHET WHEEL ........................ 6-52
CHECKING THE KICK GEAR, KICK IDLE GEAR AND RATCHET
WHEEL .................................................................................................... 6-52
INSTALLING THE KICK SHAFT ASSEMBLY .......................................... 6-52
INSTALLING THE KICK IDLE GEAR ....................................................... 6-53
SHIFT SHAFT................................................................................................. 6-54
REMOVING THE SHIFT GUIDE AND SHIFT LEVER ASSEMBLY ......... 6-56
REMOVING THE SEGMENT ................................................................... 6-56
CHECKING THE SHIFT SHAFT .............................................................. 6-56
CHECKING THE SHIFT GUIDE AND SHIFT LEVER ASSEMBLY ......... 6-56
CHECKING THE STOPPER LEVER ....................................................... 6-56
INSTALLING THE STOPPER LEVER ..................................................... 6-56
INSTALLING THE SEGMENT.................................................................. 6-57
INSTALLING THE SHIFT GUIDE AND SHIFT LEVER ASSEMBLY ....... 6-57
INSTALLING THE SHIFT SHAFT ............................................................ 6-58
INSTALLING THE SHIFT PEDAL ............................................................ 6-58
OIL PUMP AND BALANCER GEAR............................................................. 6-59
REMOVING THE BALANCER ................................................................. 6-62
CHECKING THE PRIMARY DRIVE GEAR, BALANCER DRIVE GEAR,
AND BALANCER WEIGHT GEAR .......................................................... 6-62
CHECKING THE BALANCER .................................................................. 6-62
CHECKING THE OIL PUMP .................................................................... 6-62
ASSEMBLING THE OIL PUMP ................................................................ 6-63
INSTALLING THE OIL PUMP AND BALANCER GEAR .......................... 6-63

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
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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 6-42.
Shift pedal Refer to “SHIFT SHAFT” on page 6-54.
Starter motorRefer to “ELECTRIC STARTER” on page 6-
37.
1 Engine guard 1
2 Brake pedal 1
3Spring 1
4 Cylinder head breather hose 1
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6
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3
2
1110
9
55 Nm (5.5 m kgf, 40 ft Ibf)T.R.

KICKSTATER
6-51
EAS2GBB281
KICKSTATER
Removing the kick shaft
Order Part name Q’ty Remarks
Primary driven gear Refer to “CLUTCH” on page 6-42.
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
6-52
EAS2GBB282REMOVING THE KICK SHAFT ASSEMBLY
1. Remove:
• Kick shaft assembly “1”
TIP
Unhook the torsion spring “2” from the hole “a”
in the crankcase.
EAS2GBB283CHECKING 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.
EAS2GBB284CHECKING 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.
EAS2GBB285INSTALLING 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
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KICKSTATER
6-53
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.
EAS2GBB286INSTALLING 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
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TRANSMISSION
6-83
EAS2GBB326CHECKING THE TRANSMISSION
1. Measure:
• Main axle runout
(with a centering device and dial gauge “1”)
Out of specification  Replace the main ax-
le.
2. Measure:
• Drive axle runout
(with a centering device and dial gauge “1”)
Out of specification  Replace the drive ax-
le.3. Check:
• Transmission gears
Blue discoloration/pitting/wear  Replace
the defective gear (s).
• Transmission gear dogs
Cracks/damage/rounded edges  Replace
the defective gear (s).
4. Check:
• Transmission gear movement
Rough movement  Replace the defective
gear (s).EAS2GBB327INSTALLING THE TRANSMISSION
1. Install:
• 6th pinion gear (27T) “1”
• 3rd/4th pinion gear (18T/21T) “2”
• Collar “3”
• 5th pinion gear (23T) “4”
• 2nd pinion gear (16T) “5”
(to the main axle “6”)
TIP
Before installation, apply molybdenum disulfide
oil to the inner and end surface of the idler gear
and to the inner surface of the sliding gear, then
install.
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 the collar and to the inner surface of
the sliding gear, then install.
• Apply the lithium-soap-based grease on the
O-ring. Main axle runout limit
0.08 mm (0.0032 in)
Drive axle runout limit
0.08 mm (0.0032 in)
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TRANSMISSION
6-84
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.
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 shift fork 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.
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