light YAMAHA WR 426F 2002 Service Manual

4 - 101
ENGCRANKCASE AND CRANKSHAFT
5. Install:
Dowel pin 1
O-ring 2
Crankcase (right)
To crankcase (left).
NOTE:
Fit the crankcase (right) onto the crankcase
(left). Tap lightly on the case with soft ham-
mer.
When installing the crankcase, the connect-
ing rod should be positioned at TDC (top
dead center).
6. Tighten:
Hose guide 1
Clutch cable holder 2
Bolt (crankcase)
NOTE:
Tighten the crankcase tightening bolts in
stage, using a crisscross pattern.
7. Install:
Oil delivery pipe
O-ring
Bolt (oil delivery pipe)
8. Install:
Timing chain
Timing chain guide (rear)
Bolt (timing chain guide)
9. Remove:
Sealant
Forced out on the cylinder mating sur-
face.
10. Apply:
Engine oil
To the crank pin, bearing and oil deliv-
ery hole.
11. Check:
Crankshaft and transmission operation.
Unsmooth operation → Repair.
New
T R..12 Nm (1.2 m · kg, 8.7 ft · lb)
New
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)

4 - 103
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 → Replace.
2. Inspect:
O-ring 1
Damage → Replace.
3. Check:
Gears movement
Unsmooth movement → Repair or
replace.
EC4H4600
Bearing
1. Inspect:
Bearing 1
Rotate inner race with a finger.
Rough spot/seizure → Replace.

5 - 19
CHASFRONT BRAKE AND REAR BRAKE
2. Install:
Copper washer 1
Union bolt 2
WARNING
Always use new copper washers.
CAUTION:
Install the brake hose so that its pipe por-
tion a directs as show and lightly touches
the projection b on the caliper.
New
T R..30 Nm (3.0 m · kg, 22 ft · lb)
3. Install:
Brake hose holder 1
Caliper 2
Bolt (caliper) 3
NOTE:
Fit the brake hose holder cut a over the pro-
jection b on the front fork and clamp the brake
hose.
4. Tighten:
Pad pin 4
5. Install:
Pad pin plug 5
T R..23 Nm (2.3 m · kg, 17 ft · lb)
T R..18 Nm (1.8 m · kg, 13 ft · lb)
T R..3 Nm (0.3 m · kg, 2.2 ft · lb)
EC5A5100
Rear caliper
1. Install:
Pad support 1
Brake pad 2
Pad pin 3
NOTE:
Install the brake pads with their projections
a into the caliper recesses b.
Temporarily tighten the pad pin at this point.

5 - 28
CHASFRONT FORK
EC550000
FRONT FORK
Extent of removal:1 Front fork removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removalFRONT FORK 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.
Front wheel Refer to “FRONT WHEEL AND REAR
WHEEL” section.
Front caliper Refer to “FRONT BRAKE AND REAR
BRAKE” section.
Headlight
Handlebar Refer to “HANDLEBAR” section.
1 Protector 1
2 Brake hose holder 2
3 Pinch bolt (handle crown) 2 Only loosening.
4 Cap bolt 1Loosen when disassembling the front fork.
5 Pinch bolt (under bracket) 2 Only loosening.
6 Front fork 1
1

5 - 41
CHAS
EC5B0000
HANDLEBAR
Extent of removal:1 Handlebar removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removalHANDLEBAR REMOVAL
Headlight
1 Decompression cable 1 Disconnect at the lever side.
2 Decompression lever holder 1
3 Clutch cable 1 Disconnect at the lever side.
4 Clutch lever holder 1
5“ENGINE STOP” button 1
6 Lights switch 1
7 Master cylinder 1 Refer to “REMOVAL POINTS”.
8 Throttle cable cap 1
9 Throttle cable #2 (pushed) 1 Disconnect at the throttle side.
10 Throttle cable #1 (pulled) 1 Disconnect at the throttle side.
11 Grip (right) 1 Refer to “REMOVAL POINTS”.
12 Tube guide 1
13 Cover (grip cap) 1
14 Collar 1
15 Grip (left) 1 Refer to “REMOVAL POINTS”.
16 Handlebar holder (upper) 2
17 Handlebar 1
1
HANDLEBAR

5 - 45
CHASHANDLEBAR
8. Install:
Master cylinder 1
Master cylinder bracket 2
Bolt (master cylinder bracket) 3
NOTE:
Install the bracket so that the arrow mark a
faces upward.
First tighten the bolt on the upper side of the
master cylinder bracket, and then tighten the
bolt on the lower side.
9. Install:
Lights switch 1
T R..9 Nm (0.9 m · kg, 6.5 ft · lb)
T R..2 Nm (0.2 m · kg, 1.4 ft · lb)
10. Install:
“ENGINE STOP” button 1
Clutch lever holder 2
Bolt (clutch lever holder) 3
Decompressor lever holder 4
Bolt (decompressor lever holder) 5
Clamp 6
NOTE:
The “ENGINE STOP” button, clutch lever
holder, decompression lever holder and
clamp should be installed according to the
dimensions shown.
Pass the “ENGINE STOP” button lead in the
middle of the clutch holder.
T R..4 Nm (0.4 m · kg, 2.9 ft · lb)
T R..4 Nm (0.4 m · kg, 2.9 ft · lb)
11. Install:
Clutch cable 1
Decompression cable 2
NOTE:
Apply the lithium soap base grease on the
clutch cable end and decompression cable
end.
B
2
1

5 - 47
CHAS
EC560000
STEERING
Extent of removal:1 Under bracket removal2 Bearing removal
Extent of removal Order Part name Q’ty Remarks
STEERING REMOVAL
WARNING
Support the machine securely so there is no
danger of it falling over.
Preparation for removal Hold the machine by placing the
suitable stand under the engine.
Headlight
Handlebar
Cable guide
Front fenderRefer to “HANDLEBAR” section.
1 Trip meter 1
2 Steering shaft nut 1
3 Front fork 2 Refer to “FRONT FORK” section.
4 Handle crown 1
5 Ring nut 1 Use special tool.
Refer to “REMOVAL POINTS”.
6 Under bracket 1
7Ball race cover
1
2
1
STEERING

5 - 60
CHASREAR SHOCK ABSORBER
EC580000
REAR SHOCK ABSORBER
Extent of removal:1 Rear shock absorber removal2 Rear shock absorber disassembly
Extent of removal Order Part name Q’ty Remarks
Preparation for removalREAR SHOCK ABSORBER
REMOVAL
Hold the machine by placing the
suitable stand under the engine.
WARNING
Support the machine securely so there is nodanger of it falling over.
Seat, fitting band and side covers Refer to “SEAT, FUEL TANK AND SIDE
COVERS” section in the CHAPTER 4.
Silencer Refer to “EXHAUST PIPE AND
SILENCER” section in the CHAPTER 4.
Drain the coolant. Refer to “COOLANT REPLACEMENT”
section in the CHAPTER 3.
Coolant reservoir tank Refer to “RADIATOR” section in the
CHAPTER 4.
1 Tail light connector 2
2 Band 2
3 Bolt (reservoir tank) 1
4 Clamp (air cleaner joint) 1 Only loosening.
5 Rear frame 1
6 Bolt (rear shock absorber-relay arm) 1Hold the swingarm.
7 Bolt (rear shock absorber-frame) 1
8 Rear shock absorber 1
12

5 - 67
CHASREAR SHOCK ABSORBER
8. Install:
Band 1
Tail light connector 2

6 - 1
–+ELECELECTRICAL COMPONENTS AND WIRING DIAGRAM
EC600000
ELECTRICAL
EC610000
ELECTRICAL COMPONENTS AND WIRING DIAGRAM
EC611000
ELECTRICAL COMPONENTS
1Headlight
2“ENGINE STOP” button
3Regulator
4TPS (throttle position sensor)
5Tail light
6CDI magneto
7Neutral switch
8Ignition coil
9Spark plug
0Lights switch
ACDI unitCOLOR CODE
B ................... Black
Br .................. Brown
G ................... Green
Gy ................. Gray
L .................... Blue
O ................... Orange
P ................... Pink
R ................... Red
Sb ................. Sky blue
EC612000
WIRING DIAGRAM
* Except for USA
B/L
R/WL/W
LY
L
Y
B
1B L
L
B YL
B YYYLB
5LB
YBLB
LB
3
7
4 8
9
W
R Br
G PB/YP
B Br
G W
R
O
L Y B/LL/WSb
B/L Y O
L
A
Y
Br
Gy
PGR
WB
L YL Y
B B/L
SbW
Sb
WL/W
R/WL/WL/WR/WSb
W
O
B
0
6
B GyBGy
O
L Y Sb
B/L*
B*
Sb*
Y
BL
B
B
B
B/WBB/W G/B
2
W................... White
Y.................... Yellow
B/L................. Black/Blue
B/W ............... Black/White
B/Y ................ Black/Yellow
G/B ................ Green/Black
L/W................ Blue/White
R/W ............... Red/White