2017 YAMAHA WR 250F Owners Manual

CHAIN DRIVE
5-71
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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).
c. After riveting, make sure the space “c”,
which is inside of the connecting link “3” and
inside of the connecting plate “1”, is 14.1–
14.3 mm (0.56–0.65 in).
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2. Lubricate:
•Drive chain3. Install:
• Drive sprocket
• Lock washer
• Drive sprocket nut
Refer to “ENGINE REMOVAL” on page 6-1.
ECA
NOTICE
Never install a new drive chain onto worn
drive chain sprockets; this will dramatically
shorten the drive chain’s life.
4. Adjust:
• Drive chain slack
Refer to “ADJUSTING THE DRIVE CHAIN
SLACK” on page 3-31.
ECA
NOTICE
A drive chain that is too tight will overload
the engine and other vital parts, and one
that is too loose can skip and damage the
swingarm or cause an accident. Therefore,
keep the drive chain slack within the speci-
fied limits.
Recommended lubricant
Chain lubricant suitable for O-
ring chains
Drive sprocket nut
75 Nm (7.5 m·kgf, 54 ft·lbf)
Drive chain slack (on a suitable
stand)
50.0–60.0 mm (1.97–2.36 in)
New
T R..

CHAIN DRIVE
5-72

6
ENGINE
ENGINE REMOVAL......................................................................................... 6-1
REMOVING THE SILENCER ..................................................................... 6-6
REMOVING THE EXHAUST PIPE 2.......................................................... 6-6
REMOVING THE DRIVE SPROCKET ....................................................... 6-6
REMOVING THE ENGINE ......................................................................... 6-7
CLEANING THE SPARK ARRESTER ....................................................... 6-7
CHECKING THE SILENCER AND EXHAUST PIPE.................................. 6-8
INSTALLING THE ENGINE........................................................................ 6-8
INSTALLING THE BRAKE PEDAL ............................................................ 6-9
INSTALLING THE DRIVE SPROCKET...................................................... 6-9
INSTALLING THE EXHAUST PIPE AND MUFFLER............................... 6-10
CAMSHAFT.................................................................................................... 6-12
REMOVING THE CAMSHAFT ................................................................. 6-14
CHECKING THE CAMSHAFT.................................................................. 6-15
CHECKING THE TIMING CHAIN AND CAMSHAFT SPROCKET .......... 6-16
CHECKING THE TIMING CHAIN TENSIONERS .................................... 6-16
CHECKING THE DECOMPRESSION SYSTEM...................................... 6-17
INSTALLING THE CAMSHAFTS ............................................................. 6-17
CYLINDER HEAD........................................................................................... 6-20
REMOVING THE CYLINDER HEAD........................................................ 6-22
CHECKING THE TIMING CHAIN GUIDE (INTAKE SIDE) ...................... 6-22
CHECKING THE CYLINDER HEAD ........................................................ 6-22
INSTALLING THE CYLINDER HEAD ...................................................... 6-23
VALVES AND VALVE SPRINGS................................................................... 6-24
REMOVING THE VALVES ....................................................................... 6-25
CHECKING THE VALVES AND VALVE GUIDES ................................... 6-26
CHECKING THE VALVE SEATS ............................................................. 6-27
CHECKING THE VALVE SPRINGS......................................................... 6-29
CHECKING THE VALVE LIFTERS .......................................................... 6-29
INSTALLING THE VALVES ..................................................................... 6-30
CYLINDER AND PISTON............................................................................... 6-32
REMOVING THE PISTON ....................................................................... 6-33
CHECKING THE CYLINDER AND PISTON ............................................ 6-33
CHECKING THE PISTON RINGS............................................................ 6-34
CHECKING THE PISTON PIN ................................................................. 6-35
INSTALLING THE PISTON AND CYLINDER .......................................... 6-35
ELECTRIC STARTER.................................................................................... 6-37
CHECKING THE STARTER MOTOR ...................................................... 6-39
ASSEMBLING THE STARTER MOTOR .................................................. 6-40

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

GENERATOR AND STARTER CLUTCH....................................................... 6-66
REMOVING THE GENERATOR .............................................................. 6-68
CHECKING THE STARTER CLUTCH ..................................................... 6-68
INSTALLING THE STARTER CLUTCH ................................................... 6-68
INSTALLING THE GENERATOR............................................................. 6-69
CRANKCASE................................................................................................. 6-72
DISASSEMBLING THE CRANKCASE..................................................... 6-75
REMOVING THE CRANKCASE BEARING ............................................. 6-75
CHECKING THE TIMING CHAIN, TIMING CHAIN GUIDE, OIL
STRAINER .............................................................................................. 6-75
CHECKING THE CRANKCASE ............................................................... 6-75
INSTALLING THE OIL SEAL................................................................... 6-76
ASSEMBLING THE CRANKCASE........................................................... 6-76
CRANKSHAFT ASSEMBLY AND BALANCER SHAFT............................... 6-78
REMOVING THE CRANKSHAFT ASSEMBLY ........................................ 6-79
CHECKING THE CRANKSHAFT ASSEMBLY......................................... 6-79
INSTALLING THE CRANKSHAFT ASSEMBLY....................................... 6-80
INSTALLING THE BALANCER SHAFT ................................................... 6-80
TRANSMISSION............................................................................................. 6-81
REMOVING THE TRANSMISSION ......................................................... 6-82
CHECKING THE SHIFT FORKS.............................................................. 6-82
CHECKING THE SHIFT DRUM ASSEMBLY ........................................... 6-82
CHECKING THE TRANSMISSION .......................................................... 6-83
INSTALLING THE TRANSMISSION ........................................................ 6-83

ENGINE REMOVAL
6-1
EAS2GBB225
TIP
This section is intended for those who have basic knowledge and skill concerning the servicing of
Yamaha motorcycles (e.g., Yamaha dealers, service engineers, etc.). Those who have little knowl-
edge and skill concerning servicing are requested not to undertake inspection, adjustment, disas-
sembly, or reassembly only by reference to this manual. It may lead to servicing trouble and
mechanical damage.
EAS2GBB226
ENGINE REMOVAL
Removing the exhaust pipe
Order Part name Q’ty Remarks
Refer to “INSTALLING THE EXHAUST
PIPE AND MUFFLER” on page 6-10.
Side cover (right) Refer to “GENERAL CHASSIS” on page 5-1.
Rear shock absorber assembly lower boltRefer to “REAR SHOCK ABSORBER AS-
SEMBLY” on page 5-58.
Connecting arm bolt (frame side)Refer to “REAR SHOCK ABSORBER AS-
SEMBLY” on page 5-58.
1 Silencer clamp 1 Loosen.
2 Silencer 1
3 Exhaust pipe 2 clamp 1 Loosen.
4 Exhaust pipe 2 1
105 9
26
1
66
3
84 7 (4) (6)
30 Nm (3.0 m kgf, 22 ft Ibf)T
.R.
30 Nm (3.0 m kgf, 22 ft Ibf)T
.R.
New
New
10 Nm (1.0 m kgf, 7.2 ft Ibf)T.R.
12 Nm (1.2 m kgf, 8.7 ft Ibf)T.R.12 Nm (1.2 m kgf, 8.7 ft Ibf)T.R.
20 Nm (2.0 m kgf, 14 ft Ibf)T
.R.New
LT
LT
10 Nm (1.0 m kgf, 7.2 ft Ibf)T.R.9 Nm (0.9 m kgf, 6.5 ft Ibf)T
.R.
5 Nm (0.5 m kgf, 3.6 ft Ibf)T
.R.
T
.R.*kgf 13 Nm (1.3 m , 9.4 ft lbf)
kgf, 14 ft 20 Nm (2.0 m lbf)
*

ENGINE REMOVAL
6-2
5 Exhaust pipe 1 1
6 Gaskets 3
7 Exhaust pipe 1 protector 1
8 Exhaust pipe 2 protector 1
9 Silencer cap 1
10 Spark arrester 1
For installation, reverse the removal proce-
dure.
Removing the exhaust pipe
Order Part name Q’ty Remarks
105 9
26
1
66
3
84 7 (4) (6)
30 Nm (3.0 m kgf, 22 ft Ibf)T
.R.
30 Nm (3.0 m kgf, 22 ft Ibf)T
.R.
New
New
10 Nm (1.0 m kgf, 7.2 ft Ibf)T.R.
12 Nm (1.2 m kgf, 8.7 ft Ibf)T.R.12 Nm (1.2 m kgf, 8.7 ft Ibf)T.R.
20 Nm (2.0 m kgf, 14 ft Ibf)T
.R.New
LT
LT
10 Nm (1.0 m kgf, 7.2 ft Ibf)T.R.9 Nm (0.9 m kgf, 6.5 ft Ibf)T
.R.
5 Nm (0.5 m kgf, 3.6 ft Ibf)T
.R.
T
.R.*kgf 13 Nm (1.3 m , 9.4 ft lbf)
kgf, 14 ft 20 Nm (2.0 m lbf)

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