Yamaha Wr 450 F Owners Manual

4 - 98
ENGTRANSMISSION, SHIFT CAM AND SHIFT FORK
TRANSMISSION, SHIFT CAM AND SHIFT FORK
TRANSMISSION, SHIFT CAM AND SHIFT FORK
Extent of removal:1 Shift fork, shift cam, main axle and drive axle removal
Extent of removal Order Part name Q’ty Remarks
TRANSMISSION, SHIFT CAM 
AND SHIFT FORK REMOVAL
Preparation for removal Engine Refer to “ENGINE REMOVAL” section.
Separate the crankcase. Refer to “CRANKCASE AND CRANK-
SHAFT” section.
1 Shift fork 1 1
Refer to “REMOVAL POINTS”. 2 Shift fork 2 1
3 Shift fork...

4 - 99
ENGTRANSMISSION, SHIFT CAM AND SHIFT FORK
EC4H3000
REMOVAL POINTS
Shift fork, shaft cam and transmission
1. Remove:
Shift forks
Shift cam
Main axle
Drive axle
NOTE:
Tap lightly on the transmission drive axle and
shift cam with a soft hammer to remove.
Remove assembly carefully. Note the posi-
tion of each part. Pay particular attention to
the location and direction of shift forks.
EC4H4000
INSPECTION
EC4H4200
Gears
1. Inspect:
Matching dog a 
Gear teeth b 
Shift fork groove c 
Wear/damage...

4 - 100
ENGTRANSMISSION, SHIFT CAM AND SHIFT FORK
EC4H4801
Shift fork, shift cam and segment
1. Inspect:
Shift fork 1 
Wear/damage/scratches → Replace.
2. Inspect:
Shift cam 1 
Segment 2 
Bend/wear/damage → Replace.
3. Check:
Shift fork movement
Unsmooth operation → Replace shift
fork.
NOTE:
For a malfunctioning shift fork, replace not only
the shift fork itself but the two gears each adja-
cent to the shift fork.
ASSEMBLY AND INSTALLATION
Transmission
1. Install:
5th pinion gear (25T) 1 
3rd...

4 - 101
ENGTRANSMISSION, SHIFT CAM AND SHIFT FORK
2. Install:
2nd wheel gear (26T) 1 
4th wheel gear (21T) 2 
3rd wheel gear (21T) 3 
5th wheel gear (21T) 4 
1st wheel gear (29T) 5 
O-ring 6
To drive axle 7.
NOTE:
Apply the molybdenum disulfide oil on the
1st, 2nd and 3rd wheel gears inner circum-
ference and on the end surface.
Apply the molybdenum disulfide oil on the
4th and 5th wheel gears inner circumfer-
ence.
Apply the lithium soap base grease on the O-
ring.
3. Install:
Plain washer 1...

4 - 102
ENGTRANSMISSION, SHIFT CAM AND SHIFT FORK
5. Install:
Shift fork 1 (L) 1 
Shift fork 2 (C) 2 
Shift fork 3 (R) 3 
Shift cam 4 
To main axle and drive axle.
NOTE:
Apply the molybdenum disulfide oil on the
shift fork grooves.
Mesh the shift fork #1 (L) with the 4th wheel
gear 5 and #3 (R) with the 5th wheel gear
7 on the drive axle.
Mesh the shift fork #2 (C) with the 3rd pinion
gear 6 on the main axle.
6. Install:
Transmission assembly 1 
To crankcase (left) 2.
NOTE:
Apply the engine oil...

 
5 - 1
CHAS
 
EC500000 
CHASSIS 
EC590000 
FRONT WHEEL AND REAR WHEEL 
EC598000 
FRONT WHEEL 
FRONT WHEEL AND REAR WHEEL 
Extent of removal:  
1  
 Front wheel removal  
2  
 Wheel bearing removal  
3  
 Brake disc removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removal  
FRONT WHEEL REMOVAL  
Hold the machine by placing the
suitable stand under the engine.
WARNING
 
Support the machine securely so there is no 
danger of it falling over. 
1 Trip meter cable 1
2 Hose cover 1
3 Bolt...

 
5 - 2
CHAS
 
EC598100 
REAR WHEEL 
Extent of removal: 
1  
 Rear wheel removal  
2  
 Wheel bearing removal  
3  
 Brake disc removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removal 
REAR WHEEL REMOVAL  
Hold the machine by placing the
suitable stand under the engine.
WARNING
 
Support the machine securely so there is no 
danger of it falling over. 
1 Nut (rear wheel axle) 1
2 Rear wheel axle 1
3 Chain puller 2
4 Rear wheel 1 Refer to “REMOVAL POINTS”.
5 Collar 2
6 Driven...

 
5 - 3
CHAS
 
FRONT WHEEL AND REAR WHEEL 
EC593000 
REMOVAL POINTS 
EC523101 
Rear wheel  
1. Remove: 
 
Wheel   
1  
 
NOTE:
 
Push the wheel forward and remove the drive 
chain   
2  
. 
EC513201 
Wheel bearing (if necessary)  
1. Remove: 
 
Bearing   
1  
 
NOTE:
 
Remove the bearing using a general bearing 
puller   
2  
. 
EC594000 
INSPECTION 
EC514100 
Wheel  
1. Measure: 
 
Wheel runout
Out of limit   
→  
 Repair/replace.
2. Inspect: 
 
Bearing
Rotate inner race with a finger.
Rough...

 
5 - 4
CHAS
 
FRONT WHEEL AND REAR WHEEL 
EC514200 
Wheel axle 
1. Measure: 
 
Wheel axle bends
Out of specification  
→  
 Replace.
Use the dial gauge  
1  
.
NOTE:
 
The bending value is shown by one half of the 
dial gauge reading.
WARNING
 
Do not attempt to straighten a bent axle. 
Wheel axle bending limit:
0.5 mm (0.020 in) 
EC594200 
Brake disc 
1. Measure: 
 
Brake disc deflection (only rear brake
disc)
Use the dial gauge  
1  
. 
Out of specification  
→  
 Inspect wheel
runout.
If wheel...

 
5 - 5
CHAS
 
FRONT WHEEL AND REAR WHEEL 
EC595000 
ASSEMBLY AND INSTALLATION
Front wheel 
1. Install: 
 
Bearing (left)  
1 
  
 
Spacer  
2 
  
 
Bearing (right)  
3 
  
 
Oil seal  
4 
 
NOTE:
 
 
Apply the lithium soap base grease on the
bearing and oil seal lip when installing. 
 
Use a socket that matches the outside diam-
eter of the race of the bearing. 
 
Left side of bearing shall be installed first. 
 
Install the oil seal with its manufacture’s 
marks or numbers facing outward....