2017 YAMAHA WR 250F Owners Manual

GENERATOR AND STARTER CLUTCH
6-68
EAS2GBB306REMOVING THE GENERATOR
1. Remove:
• Generator rotor nut “1”
• Washer
2. Remove:
• Generator rotor “1”
(with the rotor puller “2”)
• Woodruff key
EAS2GBB307CHECKING THE STARTER CLUTCH
1. Check:
• Starter clutch rollers
Damage/wear  Replace.
2. Check:
• Starter clutch idle gear
• Starter clutch gear
Burrs/chips/roughness/wear  Replace the
defective part (s).3. Check:
• Starter clutch gear
Damage/pitting/wear  Replace the starter
clutch gear.
4. Check:
• Damper assembly
Damage/pitting/wear  Replace the damp-
er assembly.
Check the gear of the starter motor arma-
ture.
5. Check:
• Starter clutch operation
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a. Install the starter clutch drive gear “1” onto
the starter clutch and hold the starter clutch.
b. When turning the starter clutch drive gear
clockwise “A”, the starter clutch and the
starter clutch drive gear should engage, oth-
erwise the starter clutch is faulty and must
be replaced.
c. When turning the starter clutch drive gear
counterclockwise “B”, it should turn freely,
otherwise the starter clutch is faulty and
must be replaced.
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EAS2GBB308INSTALLING THE STARTER CLUTCH
1. Install:
• Stator “1”
• Stator bolt “2” Rotor puller
90890-04142
Rotor puller
YM-04142
1
1
2
1 A
B

GENERATOR AND STARTER CLUTCH
6-69
• Crankshaft position sensor “3”
• Holder “4”
• Crankshaft position sensor bolt “5”
TIP
• Pass the AC magneto lead “6” and crankshaft
position sensor lead “7” under the holder as
shown.
• Tighten the stator bolt using the T25 bit.
• Apply the sealant to the grommet of the AC
magneto lead.
2. Install
• Starter clutch drive gear “1”
TIP
Apply the engine oil on the starter clutch drive
gear inner circumference.3. Install:
• Starter clutch “1”
To generator rotor “2”.
EAS2GBB309INSTALLING THE GENERATOR
1. Install:
• Woodruff key “1”
• Generator rotor “2”
TIP
• Clean the contact surfaces of the tapered por-
tions of the crankshaft and generator rotor.
• When installing the woodruff key, make sure
that its flat surface “a” is in parallel with the
crankshaft center line “b”.
• When installing the generator rotor, align the
keyway “c” of the generator rotor with the
woodruff key. Stator bolt
7 Nm (0.7 m·kgf, 5.1 ft·lbf)
LOCTITE®
Crankshaft position sensor bolt
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Yamaha bond No.1215
90890-85505
(Three bond No.1215®)
T R..
T R..
6
7
1
3
22
5
5
4LT
Starter clutch bolt
16 Nm (1.6 m·kgf, 12 ft·lbf)
LOCTITE®
21
LT
T R..
2 C1 1
1a b

GENERATOR AND STARTER CLUTCH
6-70
2. Install:
• Washer
• Generator rotor nut “1”
3. Install:
• Starter idle gear shaft “1”
• Bearing “2”
• Starter idle gear 2 “3”
TIP
Apply the engine oil on the starter idle gear
shaft, bearing and idle gear inner circumfer-
ence.
4. Install:
• Dowel pin
• Crankcase cover gasket
• Left crankcase cover “1”
• Lead holder “2”
• Crankcase cover bolt
• Neutral switch lead “3”
TIP
• Pass the AC magneto lead “4” under the left
crankcase cover “a” as shown.
• Tighten the bolts in stage, using a crisscross
pattern.5. Install:
• Washer “1”
• Damper assembly “2”
• Washer “3”
TIP
Apply the engine oil to the shaft and washers.
6. Install:
• Cover (damper assembly) “1”
• Bracket “2”
•Bolt “3”
• Breather hose 2 “4”
TIP
Install the cover (damper assembly) with its
mark “a” facing upward. Generator rotor nut
65 Nm (6.5 m·kgf, 47 ft·lbf)
Crankcase cover bolt
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
T R..
1
1
21
2
3
New
T R..Bolt
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
4
1a
1
2
3
21
2
3
T R..

GENERATOR AND STARTER CLUTCH
6-71
1a3
3
2
4

CRANKCASE
6-72
EAS2GBB310
CRANKCASE
Separating the crankcase
Order Part name Q’ty Remarks
Engine Refer to “ENGINE REMOVAL” on page 6-1.
PistonRefer to “CYLINDER AND PISTON” on page
6-32.
BalancerRefer to “OIL PUMP AND BALANCER
GEAR” on page 6-59.
Kick shaft assembly Refer to “KICKSTATER” on page 6-51.
Segment Refer to “SHIFT SHAFT” on page 6-54.
Generator rotorRefer to “GENERATOR AND STARTER
CLUTCH” on page 6-66.
1 Timing chain guide (exhaust side) 1
2 Timing chain guide stopper plate 1
3 Timing chain 1
4 Bolt [L = 45 mm (1.77 in)] 7
5 Bolt [L = 60 mm (2.36 in)] 2
6 Bolt [L = 75 mm (2.95 in)] 3
7 Right crankcase 1
8 Left crankcase 1
9 Dowel pin 2
3
1 5
2
6410 56
4
4
446
9117
8
9
LT
12
LT
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.
12 Nm (1.2 m kgf, 8.7 ft Ibf)T.R.
5 Nm (0.5 m kgf, 3.6 ft Ibf)T.R.

CRANKCASE
6-73
10 Crankshaft 1
11 Oil passage squeeze nozzle 1
12 Oil nozzle 1
For assembly, reverse the disassemble pro-
cedure.
Separating the crankcase
Order Part name Q’ty Remarks
3
1 5
2
6410 56
4
4
446
9117
8
9
LT
12
LT
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.
12 Nm (1.2 m kgf, 8.7 ft Ibf)T.R.
5 Nm (0.5 m kgf, 3.6 ft Ibf)T.R.

CRANKCASE
6-74
Removing the bearing and oil seal
Order Part name Q’ty Remarks
Transmission Refer to “TRANSMISSION” on page 6-81.
Shift cam and shift fork Refer to “TRANSMISSION” on page 6-81.
1 Circlip 2
2Oil seals 3
3 Bearing 11
For installation, reverse the removal proce-
dure.
LT
LT
2
3
33
3
3
3 3
33
New
1
1
2
3
New
New
LT
22 Nm (2.2 m kgf, 16 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.
LT

CRANKCASE
6-75
EAS2GBB311DISASSEMBLING THE CRANKCASE
1. Separate:
• Right crankcase
• Left crankcase
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a. Remove the crankcase bolts.
TIP
Loosen each bolt 1/4 of a turn at a time and af-
ter all the bolts are loosened, remove them.
b. Remove the right crankcase “1”.
TIP
• Place the crankcase with its left side down-
ward and split it by inserting a screwdriver tip
into the splitting slit “a” in the crankcase.
• Lift the right crankcase horizontally while light-
ly patting the crankcase splitting slit and the
engine mounting boss using a soft hammer,
and leave the crankshaft and the transmission
with the left crankcase.
ECA
NOTICE
Use soft hammer to tap on the case half.
Tap only on reinforced portions of case. Do
not tap on gasket mating surface. Work
slowly and carefully. Make sure the case
halves separate evenly. If the cases do not
separate, check for a remaining case bolt or
fitting. Do not force.c. Remove the dowel pins and O-ring.
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EAS2GBB312REMOVING THE CRANKCASE BEARING
1. Remove:
• Bearing “1”
TIP
• Remove the bearing from the crankcase by
pressing its inner race.
• Do not use the removed bearing.
EAS2GBB313CHECKING THE TIMING CHAIN, TIMING
CHAIN GUIDE, OIL STRAINER
1. Check:
• Timing chain
Stiffness  Replace the camshaft sprocket,
timing chain and crankshaft sprocket as a
set.
2. Check:
• Timing chain guide
Damage/wear  Replace
EAS2GBB314CHECKING THE CRANKCASE
1. Wash:
• Crankcase
TIP
• Wash the crankcase in a mild solvent.
• Remove any remaining gasket from the
crankcase mating surface.
1
a