Yamaha Wr250r 2008 Manual

							 
CRANKCASE 
5-57 
8 Crankcase Right 1
9 Dowel pin 2
10 Oil strainer 1
11 Nozzle 1
12 Left crankcase 1
For installation, reverse the removal proce-
dure.  
Separating the crankcase
Order Job/Parts to remove Q’ty Remarks
12 3 45
6 7
8
9
9
1011
12
LT
LT
LT
LT
T R..10 Nm (1.0 m • kg, 7.2 ft • Ib) 
T R..10 Nm (1.0 m • kg, 7.2 ft • Ib) 
T R..10 Nm (1.0 m • kg, 7.2 ft • Ib) 
T R..10 Nm (1.0 m • kg, 7.2 ft • Ib) T R..10 Nm (1.0 m • kg, 7.2 ft • Ib) T R..4 Nm (0.4 m • kg, 2.9 ft • Ib) 
LT 
						

							 
CRANKCASE 
5-58 
Removing the bearing and oil seal
Order Job/Parts to remove Q’ty Remarks  
Crankshaft assemblyRefer to“CRANKSHAFT ASSEMBLY AND 
BALANCER SHAFT” on page 5-61.
Transmission assembly Refer to“TRANSMISSION” on page 5-64.
1 Bearing cover plate 1
2 Bearing cover plate 2
3 Stopper plate 2
4 Oil seal 2
5 Bearing 7
6 Needle bearing 2
For installation, reverse the removal proce-
dure.
12
3
4 5
55 5
6
6
LT
LT
LT
E
E
E
E
E
E
T R..10 Nm (1.0 m • kg, 7.2 ft • Ib) 
T R..10 Nm (1.0 m • kg, 7.2 ft • Ib)  
						

							 
CRANKCASE 
5-59 
EAS25570 
DISASSEMBLING THE CRANKCASE 
1. Remove: 
 
Crankcase bolts
NOTE:
 
Loosen each bolt 1/4 of a turn at a time, in stag-
es and in a crisscross pattern. After all of the 
bolts are fully loosened, remove them.
2. Turn: 
 
Shift drum segment
NOTE:
 
Turn the shift drum segment to the position
shown in the illustration. In this position, the shift
drum segment’s teeth will not contact the crank- 
case during crankcase separation.
3. Remove: 
 
Right crankcase
CAUTION:
 
 ECA13910 
 
First check that the shift drum segment’s
teeth and the drive axle circlip are properly
positioned, then remove the right crank-
case. 
 
Do not damage the crankcase mating sur- 
faces. 
EAS32D1015 
CHECKING THE TIMING CHAIN, TIMING 
CHAIN GUIDE, OIL STRAINER, NOZZLE, 
DELIVERY PIPE 
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.
3. Check: 
 
Oil strainer
Obstruction  
→ 
 Blow out with compressed air.
Cracks/damage  
→ 
 Replace.4. Check: 
 
Nozzle 
 
Delivery pipe
Obstruction  
→  
 Blow out with compressed air.
Bends/cracks/damage  
→  
 Replace. 
EAS25580 
CHECKING THE CRANKCASE 
1. Thoroughly wash the crankcase halves in a
mild solvent.
2. Thoroughly clean all the gasket surfaces and
crankcase mating surfaces.
3. Check: 
 
Crankcase
Cracks/damage  
→  
 Replace. 
 
Oil delivery passages
Obstruction  
→ 
 Blow out with compressed air. 
EAS25700 
ASSEMBLING THE CRANKCASE 
1. Install: 
 
Nozzle “1” 
 
Oil strainer “2” 
 
Bearing cover plate “3” 
 
Oil delivery pipe “4” 
Nozzle bolt
10 Nm (1.0 m•kg, 7.2 ft•lb)
LOCTITE®
Oil delivery bolt
10 Nm (1.0 m•kg, 7.2 ft•lb)
LOCTITE®
Oil strainer bolt
10 Nm (1.0 m•kg, 7.2 ft•lb)
LOCTITE®
Bearing cover plate
10 Nm (1.0 m•kg, 7.2 ft•lb)
LOCTITE®
TR.. 
						

							 
CRANKCASE 
5-60 
2. Thoroughly clean all the gasket mating sur-
faces and crankcase mating surfaces.
3. Apply: 
 
Sealant
(onto the crankcase mating surfaces)
4. Install: 
 
Crankcase (to the left crankcase)
NOTE:
 
 
Turn the shift drum segment as shown so that
the shift drum segment teeth do not contact the
crankcase during its assembling. 
 
Tighten the bolts in a crisscross pattern in two 
(2) stages, with 1/4 turn each. 
Yamaha bond No. 1215 (Three
Bond No.1215®)
90890-85505
Crankcase bolt
10 Nm (1.0 m•kg, 7.2 ft•lb)
431
2
TR..
 
1. M6   
×  
 90 mm
2. M6   
×  
 65 mm
3. M6   
×  
 45 mm
2
1
3
2
3
2
32 
						

							 
CRANKSHAFT ASSEMBLY AND BALANCER SHAFT 
5-61 
EAS25970 
CRANKSHAFT ASSEMBLY AND BALANCER SHAFT 
Removing the crankshaft assembly and balancer shaft
Order Job/Parts to remove Q’ty Remarks  
Crankcase.Separate.
Refer to“CRANKCASE” on page 5-56.
1 Balancer shaft 1
2 Crankshaft assembly 1
For installation, reverse the removal proce-
dure.
1 2 
						

							 
CRANKSHAFT ASSEMBLY AND BALANCER SHAFT 
5-62 
EAS26000 
REMOVING THE CRANKSHAFT ASSEMBLY 
1. Remove: 
 
Crankshaft assembly “1”
NOTE:
 
 
Remove the crankshaft assembly by using the 
crankcase separating tool “2”. 
EAS26060 
CHECKING THE CRANKSHAFT ASSEMBLY 
1. Measure: 
 
Crankshaft runout
Out of specification  
→ 
 Replace the crank-
shaft, bearing or both.
NOTE:
 
Turn the crankshaft slowly.
2. Measure: 
 
Big end side clearance
Out of specification  
→ 
 Replace the big end
bearing, crankshaft pin, or connecting rod.3. Measure: 
 
Crankshaft width
Out of specification   
→  
 Replace the crank-
shaft.
4. Check: 
 
Crankshaft sprocket “1”
Damage   
→  
 Replace the crankshaft.
5. Check: 
 
Crankshaft journal oil passage
Obstruction   
→  
 Blow out with compressed air. 
EAS26210 
INSTALLING THE CRANKSHAFT 
ASSEMBLY 
1. Install: 
 
Crankshaft assembly
NOTE:
 
Install the crankshaft assembly with the crank-
shaft installer pot “1”, crankshaft installer bolt  
Crankcase separating tool
90890-01135
Crankcase separator
YU-01135-B
Runout limit C
0.030 mm (0.0012 in)
Big end side clearance D
0.350 
– 
0.650 mm (0.0138 
– 
0.0256
in) 
Width A
61.95  
–  
62.00 mm (2.439  
–  
2.441 in)
1 
						

							 
CRANKSHAFT ASSEMBLY AND BALANCER SHAFT 
5-63 
“2”, adapter (M12) “3” and spacer “4”.
CAUTION:
 
 ECA13970 
To avoid scratching the crankshaft and to
ease the installation procedure, lubricate the
oil seal lips with lithium-soap-based grease 
and each bearing with engine oil.
NOTE:
 
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. 
Crankshaft installer pot “1”
90890-01274
Installing pot
YU-90058
Crankshaft installer bolt “2”
90890-01275
Bolt
YU-90060
Adapter (M12) “3”
90890-01278
Adapter #3
YU-90063
Spacer (crankshaft installer) “4”
90890-04081
Pot spacer
YM-91044
4
3
2
1 
						

							 
TRANSMISSION 
5-64 
EAS26241 
TRANSMISSION 
Removing the transmission, shift drum assembly, and shift forks
Order Job/Parts to remove Q’ty Remarks  
CrankcaseSeparate.
Refer to“CRANKCASE” on page 5-56.
1 Shift fork guide bar 1
2 Shift drum 1
3 Shift fork-R 1
4 Shift fork-C 1
5 Shift fork-L 1
6 Main axle assembly 1
7 Drive axle assembly 1
8 O-ring 1
9 Collar 1
For installation, reverse the removal proce-
dure.
1
23
4
5 67
8
9
E
E
E 
						

							 
TRANSMISSION 
5-65 
Disassembling the transmission
Order Job/Parts to remove Q’ty Remarks  
1 2nd pinion gear 1
2 6th pinion gear 1
3 3rd pinion gear 1
4 Circlip 1
5 Washer 1
6 5th pinion gear 1
7 Main axle 1
8 Circlip 1
9 Plain washer 1
10 1st wheel gear 1
11 Washer 1
12 Collar 1
13 5th wheel gear 1
14 Circlip 1
15 Washer 1
16 4th wheel gear 1
17 3rd wheel gear 1
18 6th wheel gear 1
19 Circlip 1
20 Washer 1
21 2nd wheel gear 1
1 2 3 4 5 6 7
8
9
10
11 12
13
14
15
16
17
18 19
20
21
22
M
M
M
M
M
M 
						

							 
TRANSMISSION 
5-66 
22 Drive axle 1
For installation, reverse the removal proce-
dure.  
Disassembling the transmission
Order Job/Parts to remove Q’ty Remarks
1 2 3 4 5 6 7
8
9
10
11 12
13
14
15
16
17
18 19
20
21
22
M
M
M
M
M
M