2002 YAMAHA WR 426F steering

2 - 38
SPECCABLE ROUTING DIAGRAM
EC240000
CABLE ROUTING DIAGRAM
1Hose guide
2Brake hose
3Regulator
4Fuel tank breather hose
5Oil tank breather hose
6Clamp
7Sub wire harness
8Tail light lead
9TPS (throttle position sensor) lead
0Neutral switch lead
AOil hose
BCylinder head breather hose
CHose holder
DCDI magneto lead
EClutch cable
FDecompression cable
GLights switch lead
HCarburetor breather hose
IOverflow hose
JCoolant reservoir tank breather hoseÅPass the fuel tank breather
hose behind handlebar, then
insert it into the steering shaft
hole.
ıPass the decompression
cable, regulator lead and lights
switch lead under where the oil
hose is attached.
ÇFasten the CDI magneto lead,
neutral switch lead and lights
switch lead to the frame with a
plastic locking tie.
ÎFasten the sub wire harness
and lights switch lead to the
frame in front of the protector
of the sub wire harness with a
plastic locking tie and cut off
the tie end.‰Pass the cylinder head
breather hose along the right
side of the oil tank breather
hose.
ÏFasten the sub wire harness
to the frame with a plastic
locking tie ends at the lower
left of the frame and cut off
the tie end. For fastening,
pass the plastic locking tie
through the upper holes in the
engine brackets.
ÌPass the sub wire harness
between the engine brackets.
ÓFasten the TPS lead (in the
sub wire harness) under the
frame so that it does not con-
tact the carburetor.

3 - 3
INSP
ADJ
MAINTENANCE INTERVALS
* marked: For USAFRONT FORKS
Inspect and adjust
Replace oil
Replace oil seal
●
●●
●
●
Suspension oil “01”
FRONT FORK OIL SEAL AND DUST
SEAL
Clean and lube
●●Lithium base grease
REAR SHOCK ABSORBER
Inspect and adjust
Lube
Retighten
●
●●
●●(After
rain ride)
●Molybdenum disulfide
grease
CHAIN GUARD AND ROLLERS
Inspect
●●
SWINGARM
Inspect, lube and retighten
●●
Molybdenum disulfide
grease
RELAY ARM, CONNECTING ROD
Inspect, lube and retighten
●●
Molybdenum disulfide
grease
STEERING HEAD
Inspect free play and retighten
Clean and lube
Replace bearing
●●
●
●Lithium base grease
TIRE, WHEELS
Inspect air pressure, wheel run-out,
tire wear and spoke looseness
Retighten sprocket bolt
Inspect bearings
Replace bearings
Lubricate
●
●●
●
●
●●
Lithium base grease
THROTTLE, CONTROL CABLE
Check routing and connection
Lubricate
Inspect and clean (throttle cable)
●
●
●●
●
●Yamaha cable lube or
SAE 10W-30 motor oil
Inspect dirt and wear on
the throttle cable on the
carburetor side. ItemAfter
break-inEvery
race
Every
third
or
500 km
(300 mi)Every
fifth
or
1,000 km
(600 mi)
As re-
quiredRemarks

3 - 4
INSP
ADJ
PRE-OPERATION INSPECTION AND MAINTENANCE
EC320000
PRE-OPERATION INSPECTION AND MAINTENANCE
Before riding for break-in operation, practice or a race, make sure the machine is in good operating
condition.
Before using this machine, check the following points.
GENERAL INSPECTION AND MAINTENANCE
Item Routine Page
CoolantCheck that coolant is filled up to the radiator filler cap.
Check that the coolant level is correct in the coolant reservoir
tank.
Check the cooling system for leakage.P.3-5 ~ 9
FuelCheck that a fresh gasoline is filled in the fuel tank. Check the
fuel line for leakage.P.1-14
Engine oilCheck that the oil level is correct. Check the crankcase and
frame oil line for leakage.P.3-14 ~ 18
Gear shifter and clutchCheck that gears can be shifted correctly in order and that the
clutch operates smoothly.P.3-10
Throttle grip/HousingCheck that the throttle grip operation and free play are correctly
adjusted. Lubricate the throttle grip and housing, if necessary.P.3-10 ~ 11
Brakes Check the play of front brake and effect of front and rear brake. P.3-26 ~ 32
ChainCheck chain slack and alignment. Check that the chain is lubri-
cated properly.P.3-33 ~ 36
WheelsCheck for excessive wear and tire pressure. Check for loose
spokes and have no excessive play.P.3-44 ~ 45
SteeringCheck that the handlebar can be turned smoothly and have no
excessive play.P.3-45 ~ 46
Front forks and rear shock
absorberCheck that they operate smoothly and there is no oil leakage. P.3-36 ~ 43
Cables (wires)Check that the clutch and throttle cables move smoothly. Check
that they are not caught when the handlebars are turned or
when the front forks travel up and down.—
Muffler Check that the muffler is tightly mounted and has no cracks.—
Sprocket Check that the driven sprocket tightening bolt is not loose. P.3-33
Lubrication Check for smooth operation. Lubricate if necessary. P.3-47
Bolts and nuts Check the chassis and engine for loose bolts and nuts. P.1-19
Lead connectorsCheck that the CDI magneto, CDI unit, and ignition coil are con-
nected tightly.P.1-6
SettingsIs the machine set suitably for the condition of the racing course
and weather or by taking into account the results of test runs
before racing? Are inspection and maintenance completely
done?P.7-1 ~ 22

3 - 45
INSP
ADJ
STEERING HEAD INSPECTION AND ADJUSTMENT
2. Inspect:
Bearing free play
Exist play → Replace.
STEERING HEAD INSPECTION AND
ADJUSTMENT
1. Elevate the front wheel by placing a suit-
able stand under the engine.
2. Check:
Steering shaft
Grasp the bottom of the forks and gen-
tly rock the fork assembly back and
forth.
Free play → Adjust steering head.
3. Check:
Steering smooth action
Turn the handlebar lock to lock.
Unsmooth action → Adjust steering ring
nut.
4. Adjust:
Steering ring nut
Steering ring nut adjustment steps:
Remove the headlight.
Remove the handlebar and handle crown.
Loosen the ring nut 1 using the ring nut
wrench 2.
Ring nut wrench:
YU-33975/90890-01403

3 - 46
INSP
ADJ
STEERING HEAD INSPECTION AND ADJUSTMENT
Tighten the ring nut 3 using ring nut
wrench 4.
NOTE:
Set the torque wrench to the ring nut wrench
so that they form a right angle.
Ring nut wrench:
YU-33975/90890-01403
T R..
Ring nut (initial tightening):
38 Nm (3.8 m • kg, 27 ft • lb)
Loosen the ring nut one turn.
Retighten the ring nut using the ring nut
wrench.
WARNING
Avoid over-tightening.
T R..
Ring nut (final tightening):
7 Nm (0.7 m • kg, 5.1 ft • lb)
Check the steering shaft by turning it lock
to lock. If there is any binding, remove the
steering shaft assembly and inspect the
steering bearings.
Install the handle crown 5, steering shaft
nut 6, handlebar 7, handlebar holder 8
and headlight 9.
NOTE:
The upper handlebar holder should be
installed with the punched mark a for-
ward.
Insert the end of fuel breather hose 0 into
the hole of the steering shaft.
CAUTION:
First tighten the bolts on the front side of
the handlebar holder, and then tighten
the bolts on the rear side.
T R..
Steering shaft nut:
145 Nm (14.5 m • kg, 105 ft • lb)
Handlebar upper holder:
28 Nm (2.8 m • kg, 20 ft • lb)
Pinch bolt (handle crown):
23 Nm (2.3 m • kg, 17 ft • lb)
Headlight:
7 Nm (0.7 m • kg, 5.1 ft • lb)

5 - 46
CHAS

12. Adjust:

Clutch lever free play
Refer to “CLUTCH ADJUSTMENT”
section in the CHAPTER 3.

Decompression lever free play
Refer to “DECOMPRESSION LEVER
ADJUSTMENT” section in the CHAP-
TER 3.
13. Fasten the decompression cable
1
and
clutch cable
2
with a clamp
3
.
1
2
3

14. Insert the end of the fuel breather hose
1
into the hole of the steering shaft.
HANDLEBAR

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 - 48
CHASSTEERING
Extent of removal Order Part name Q’ty Remarks
8 Bearing (upper) 1
9 Bearing (lower) 1 Refer to “REMOVAL POINTS”.
10Ball race
2Refer to “REMOVAL POINTS”.
2