2002 YAMAHA WR 426F check oil

1 - 8
GEN
INFO
SPECIAL TOOLS
YU-33975, 90890-01403 Ring nut wrench
This tool is used when tighten the steering ring nut to
specification.YU-33975 90890-01403
YM-1423, 90890-01423 Damper rod holder
Use this tool to remove and install the damper rod.YM-1423 90890-01423
YM-01442, 90890-01442 Fork seal driver
This tool is used when install the fork oil seal.YM-01442 90890-01442
YU-3112-C, 90890-03112 Pocket tester
Use this tool to inspect the coil resistance, output
voltage and amperage.YU-3112-C 90890-03112
YU-8036-B
90890-03113Inductive tachometer
Engine tachometer
This tool is needed for observing engine rpm.YU-8036-B 90890-03113
YM-33277-A, 90890-03141 Timing light
This tool is necessary for checking ignition timing.YM-33277-A 90890-03141
YM-4019, 90890-04019 Valve spring compressor
This tool is needed to remove and install the valve
assemblies.YM-4019 90890-04019
YM-91042, 90890-04086 Clutch holding tool
This tool is used to hold the clutch when removing or
installing the clutch boss securing nut.YM-91042 90890-04086
YM-4116, 90890-04116
YM-4097, 90890-04097Valve guide remover
Intake (4.5 mm)
Exhaust (5.0 mm)
This tool is needed to remove and install the valve
guide.YM-4116
YM-409790890-04116
90890-04097
Part number Tool name/How to use Illustration

2 - 10
SPECMAINTENANCE SPECIFICATIONS (WR426F)
Item Standard
Lubrication chart:
Pressure feed
Splashed scavenge
Oil strainer
Oil pan Oil pump rotor 2
Oil pump rotor 1
Oil tank
Oil filter
Check ball
Cylinder head
Crank pinPiston pinPiston
Drive axleMain axleTransmission gears
Camshaft
Valve lifter

2 - 12
SPECMAINTENANCE SPECIFICATIONS (WR426F)
Oil drain bolt (crankcase) M12 × 1.5 1 20 2.0 1.4
Oil drain bolt (frame) M8 × 1.25 1 23 2.3 17
Oil strainer (frame) M18 × 1.5 1 90 9.0 65
Crankcase bearing stopper M6 × 1.0 15 10 1.0 7.2
Drive axle oil seal stopper M6 × 1.0 2 10 1.0 7.2
Ratchet wheel guide M6 × 1.0 2 12 1.2 8.7
Kick crank M8 × 1.25 1 33 3.3 24
Primary drive gear M20 × 1.0 1 75 7.5 54
Clutch boss M20 × 1.0 1 75 7.5 54
Clutch spring M6 × 1.0 6 8 0.8 5.8
Balancer driven gear M14 × 1.0 1 50 5.0 36
Balancer weight plate M6 × 1.0 3 10 1.0 7.2
Drive sprocket M20 × 1.0 1 75 7.5 54
Shift guide M6 × 1.0 2 10 1.0 7.2
Stopper lever M6 × 1.0 1 10 1.0 7.2
Segment M8 × 1.25 1 30 3.0 22
Neutral switch M5 × 0.8 2 4 0.4 2.9 Part to be tightened Thread size Q’tyTightening torque
Nm m·kg ft·lb
NOTE:
- marked portion shall be checked for torque tightening after break-in or before each race.

2 - 27
SPECMAINTENANCE SPECIFICATIONS (WR400F)
Item Standard
Lubrication chart:
Pressure feed
Splashed scavenge
Oil strainer
Oil pan Oil pump rotor 2
Oil pump rotor 1
Oil tank
Oil filter
Check ball
Cylinder head
Crank pinPiston pinPiston
Drive axleMain axleTransmission gears
Camshaft
Valve lifter

2 - 29
SPECMAINTENANCE SPECIFICATIONS (WR400F)
NOTE:
- marked portion shall be checked for torque tightening after break-in or before each race. Oil drain bolt (crankcase) M12 × 1.5 1 20 2.0 1.4
Oil drain bolt (frame) M8 × 1.25 1 23 2.3 17
Oil strainer (frame) M18 × 1.5 1 90 9.0 65
Crankcase bearing stopper M6 × 1.0 15 10 1.0 7.2
Drive axle oil seal stopper M6 × 1.0 2 10 1.0 7.2
Ratchet wheel guide M6 × 1.0 2 12 1.2 8.7
Kick crank M8 × 1.25 1 33 3.3 24
Primary drive gear M20 × 1.0 1 75 7.5 54
Clutch boss M20 × 1.0 1 75 7.5 54
Clutch spring M6 × 1.0 5 8 0.8 5.8
Balancer driven gear M14 × 1.0 1 50 5.0 36
Balancer weight plate M6 × 1.0 3 10 1.0 7.2
Drive sprocket M20 × 1.0 1 75 7.5 54
Shift guide M6 × 1.0 2 10 1.0 7.2
Stopper lever M6 × 1.0 1 10 1.0 7.2
Segment M8 × 1.25 1 30 3.0 22
Neutral switch M5 × 0.8 2 4 0.4 2.9 Part to be tightened Thread size Q’tyTightening torque
Nm m·kg ft·lb

3 - 1
INSP
ADJ
MAINTENANCE INTERVALS
EC300000
REGULAR INSPECTION AND ADJUSTMENTS
MAINTENANCE INTERVALS
The following schedule is intended as a general guide to maintenance and lubrication. Bear in mind
that such factors as weather, terrain, geographical location, and individual usage will alter the
required maintenance and lubrication intervals. If you are a doubt as to what intervals to follow in
maintaining and lubricating your machine, consult your Yamaha dealer.
ItemAfter
break-inEvery
race
Every
third
or
500 km
(300 mi)Every
fifth
or
1,000 km
(600 mi)
As re-
quiredRemarks
ENGINE OIL
Replace
●●
OIL FILTER
Clean
●●
VALVES
Check the valve clearances.
Inspect
Replace
●●
●
●The engine must be cold.
Check the valve seats and
valve stems for wear.
VALVE SPRINGS
Inspect
Replace
●
●Check the free length and
the tilt.
VALVE LIFTERS
Inspect
Replace
●
●Check for scratches and
wear.
CAMSHAFTS
Inspect
Replace
●
●Inspect the camshaft sur-
face.
CAMSHAFT SPROCKETS
Inspect
Replace
●
●Check for wear on the
teeth and for damage.
PISTON
Inspect
Clean
Replace
●●
●
●Inspect crack
Remove carbon
PISTON RING
Inspect
Replace
●
●●Check ring end gap
PISTON PIN
Inspect
Replace
●
●
CYLINDER HEAD
Inspect and clean
●
Remove carbon
Change gasket
CYLINDER
Inspect and clean
Replace
●
●Inspect score marks
Inspect wear
CLUTCH
Inspect and adjust
Replace
●●
●
Inspect housing, friction
plate, clutch plate and
spring
TRANSMISSION
Inspect
Replace bearing
●
●

3 - 2
INSP
ADJ
MAINTENANCE INTERVALS
SHIFT FORK, SHIFT CAM, GUIDE BAR
Inspect
●Inspect wear
ROTOR NUT
Retighten
●●
MUFFLER
Inspect and retighten
Clean
Replace
●●
●
●
*Whichever comes first
*SPARK ARRESTER
Clean
(Every
six
months)
●
CRANK
Inspect and clean
●●
CARBURETOR
Inspect, adjust and clean
●●
When using a high-pres-
sure washer, make sure
that water does not enter
the accelerator pump.
SPARK PLUG
Inspect and clean
Replace
●●
●
DRIVE CHAIN
Lubricate, slack, alignment
Replace
●●
●
Use chain lube
Chain slack: 40 ~ 50 mm
(1.6 ~ 2.0 in)
COOLING SYSTEM
Check coolant level and leakage
Check radiator cap operation
Replace coolant
Inspect hoses
●●
●●
●
Every two years
OUTSIDE NUTS AND BOLTS
Retighten
●●
Refer to “STARTING AND
BREAK-IN” section in the
CHAPTER 1.
AIR FILTER
Clean and lubricate
Replace
●●
●Use foam air-filter oil
OIL STRAINER (frame)
Clean
●
FRAME
Clean and inspect
●●
FUEL TANK, COCK
Clean and inspect
●●
BRAKES
Adjust lever position and pedal height
Lubricate pivot point
Check brake disc surface
Check fluid level and leakage
Retighten brake disc bolts, caliper
bolts, master cylinder bolts and union
bolts
Replace pads
Replace brake fluid
●
●
●
●
●●
●
●
●
●
●
●
Every one year ItemAfter
break-inEvery
race
Every
third
or
500 km
(300 mi)Every
fifth
or
1,000 km
(600 mi)
As re-
quiredRemarks


3

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