2017 YAMAHA WR 250F Owners Manual

CRANKCASE
6-76
2. Check:
• Crankcase
Crack/damage  Replace.
• Oil delivery passages
Obstruction  Blow out with compressed
air.
EAS2GBB315INSTALLING THE OIL SEAL
1. Install:
• Oil seal “1”
(to left crankcase)
EAS2GBB316ASSEMBLING THE CRANKCASE
1. Install:
• Bearing cover plate screw
TIP
Install the bearing by pressing its outer race
parallel.
2. Apply:
• Sealant
(to the crankcase mating surface)3. Install:
• Oil nozzle “1”
• Dowel pin “2”
• Crankcase “3”
(to the left crankcase)
TIP
• Apply the lithium-soap-based grease on the
O-ring.
• Fit the right crankcase onto the left crankcase.
Tap lightly on the case with soft hammer.
• When installing the crankcase, the connecting
rod should be positioned at top dead center
(TDC).
• Tighten the bolts in a crisscross pattern in two
(2) stages, with 1/4 turn each. Installed depth “a”
4.5–5.0 mm (0.18–0.20 in)
Bearing cover plate screw
12 Nm (1.2 m·kgf, 8.7 ft·lbf)
LOCTITE®
Bearing cover plate screw (crank-
shaft)
22 Nm (2.2 m·kgf, 16 ft·lbf)
LOCTITE®
Yamaha bond No. 1215
90890-85505
(Three bond No.1215®)
New
a 1
T R..
Oil nozzle bolt
5 Nm (0.5 m·kgf, 3.6 ft·lbf)
LOCTITE®
Crankcase bolt
12 Nm (1.2 m·kgf, 8.7 ft·lbf)
T R..
T R..

CRANKCASE
6-77
4. 45 mm (1.77 in)
5. 60 mm (2.36 in)
6. 75 mm (2.95 in)
a. Hexagon socket head bolt without flange
b. Hexagon socket head bolt with flange
5
4
54
446 6 6
4
ab2
1LT
23
6

CRANKSHAFT ASSEMBLY AND BALANCER SHAFT
6-78
EAS2GBB317
CRANKSHAFT ASSEMBLY AND BALANCER SHAFT
Removing the crankshaft assembly and balancer shaft
Order Part name Q’ty Remarks
CrankcaseSeparate.
Refer to “CRANKCASE” on page 6-72.
Transmission Refer to “TRANSMISSION” on page 6-81.
1 Balancer shaft 1
2 Crankshaft assembly 1
For installation, reverse the removal proce-
dure.
M
M
1
2

CRANKSHAFT ASSEMBLY AND BALANCER SHAFT
6-79
EAS2GBB318REMOVING THE CRANKSHAFT ASSEMBLY
1. Remove:
• Crankshaft assembly “1”
TIP
Remove the crankshaft assembly by using the
crankcase separating tool “2”.
EAS2GBB319CHECKING THE CRANKSHAFT ASSEMBLY
1. Measure:
• Crankshaft runout
Out of specification  Replace the crank-
shaft, bearing or both.
TIP
Turn the crankshaft slowly.2. Measure:
• Big end side clearance “a”
Out of specification  Replace the big end
bearing, crankshaft pin, or connecting rod.
3. Measure:
• Crank assembly width “a”
Out of specification  Replace the crank-
shaft. Crankcase separating tool
90890-04152
Crankcase separating tool
YU-A9642
Runout limit
0.030 mm (0.0012 in)
2
1
Big end side clearance
0.150–0.450 mm (0.0059–0.0177
in)
Crank assembly width
55.95–56.00 mm (2.203–2.205 in)

CRANKSHAFT ASSEMBLY AND BALANCER SHAFT
6-80
4. Check:
• Crankshaft sprocket “1”
Damage  Replace the crankshaft.
5. Check:
• Crankshaft journal oil passage
Obstruction  Blow out with compressed
air.
EAS2GBB320INSTALLING THE CRANKSHAFT ASSEM-
BLY
1. Install:
• Crankshaft assembly
TIP
Install the crankshaft assembly with the crank-
shaft installer pot “1”, crankshaft installer bolt
“2”, adapter (M12) “3” and spacer “4”.
ECA
NOTICE
• To avoid scratching the crankshaft and to
ease the installation procedure, lubricate
the oil seal lips with lithium-soap-based
grease.
• In order to prevent the crankshaft seizure,
apply molybdenum disulfide grease.
TIP
Hold the connecting rod at top dead center
(TDC) with one hand while turning the nut of the
crankshaft installer bolt with the other. Turn the
crankshaft installer bolt until the crankshaft as-
sembly bottoms against the bearing.
EAS2GBB321INSTALLING THE BALANCER SHAFT
1. Install:
• Balancer shaft “1”
TIP
Apply the molybdenum grease to the part “a”
where the balancer shaft fit into the bearing.
ECA
NOTICE
Do not apply the molybdenum grease to the
balancer shaft thread. Crankshaft installer pot
90890-01274
Installing pot
YU-90058
Crankshaft installer bolt
90890-01275
Bolt
YU-90060
Adapter (M12)
90890-01278
Adapter #3
YU-90063
Spacer (crankshaft installer)
90890-04081
Pot spacer
YM-91044
1
M
1
a

TRANSMISSION
6-81
EAS2GBB322
TRANSMISSION
Removing the transmission, shift drum assembly, and shift forks
Order Part name Q’ty Remarks
Engine Refer to “ENGINE REMOVAL” on page 6-1.
CrankcaseSeparate.
Refer to “CRANKCASE” on page 6-72.
1 Main axle 1
2 Drive axle 1
3 Long shift fork guide bar 1
4 Short shift fork guide bar 1
5Spring 4
6 Shift cam 1
7 Shift fork 3 (R) 1
8 Shift fork 2 (C) 1
9 Shift fork 1 (L) 1
10 Collar 1
For installation, reverse the removal proce-
dure.
2
10
1
53
4 578
69
M
M
M
M
EE
E
E
LS
New
M

TRANSMISSION
6-82
EAS2GBB323REMOVING THE TRANSMISSION
1. Remove:
• Long shift fork guide bar “1”
• Short shift fork guide bar “2”
• Shift cam “3”
• Shift fork 3 “4”
• Shift fork 2 “5”
• Shift fork 1 “6”
• Main axle “7”
• Drive axle “8”
• Collar “9”
TIP
• Remove assembly with the collar “9” installed
to the crankcase.
• Make a note of the position of each part. Pay
particular attention to the location and direc-
tion of shift forks.
• Remove the main axle and the drive axle all
together by tapping the drive axle lightly with
a soft hammer.
EAS2GBB324CHECKING THE SHIFT FORKS
1. Check:
• Shift fork cam follower “1”
• Shift fork pawl “2”
Bends/damage/scoring/wear  Replace the
shift fork.2. Check:
• Shift fork guide bar
Roll the shift fork guide bar on a flat surface.
Bends  Replace.
EWA
WARNING
Do not attempt to straighten a bent shift fork
guide bar.
3. Check:
• Shift fork movement
(along the shift fork guide bar)
Rough movement  Replace the shift forks
and shift fork guide bar as a set.
EAS2GBB325CHECKING THE SHIFT DRUM ASSEMBLY
1. Check:
• Shift drum groove
Damage/scratches/wear  Replace the
shift drum assembly.
• Shift drum segment “1”
Damage/wear  Replace the shift drum as-
sembly.
1
4
62
5
3
8
7
9

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)
34
2
1
6
5
M
New