2002 YAMAHA WR 426F oil pressure

2 - 3
SPECGENERAL SPECIFICATIONS (WR426F)
Tire:
Type With tube
Size (front) 80/100-21 51M (USA, CDN, ZA)
90/90-21 54R (EUROPE, AUS, NZ)
Size (rear) 110/100-18 64M (USA, CDN, ZA)
130/90-18 69R (EUROPE, AUS, NZ)
Tire pressure (front and rear) 100 kPa (1.0 kgf/cm
2, 15 psi)
Brake:
Front brake type Single disc brake
Operation Right hand operation
Rear brake type Single disc brake
Operation Right foot operation
Suspension:
Front suspension Telescopic fork
Rear suspension Swingarm (link type monocross suspension)
Shock absorber:
Front shock absorber Coil spring/oil damper
Rear shock absorber Coil spring/gas, oil damper
Wheel travel:
Front wheel travel 300 mm (11.8 in)
Rear wheel travel 315 mm (12.4 in)
Electrical:
Ignition system CDI magneto
Headlight type: Quartz bulb (halogen)
Bulb wattage × quantity:
Headlight 12 V 60/55 W × 1
Tail light 12 V 21/5 W × 1

2 - 9
SPECMAINTENANCE SPECIFICATIONS (WR426F)
Lubrication system:
Oil filter type Wire mesh type ----
Oil pump type Trochoid type ----
Tip clearance “A”0.12 mm or less
(0.0047 in or less)0.20 mm
(0.008 in)
Tip clearance “B”0.09 ~ 0.17 mm
(0.0035 ~ 0.0067 in)0.24 mm
(0.009 in)
Side clearance 0.03 ~ 0.10 mm
(0.0012 ~ 0.0039 in)0.17 mm
(0.007 in)
Bypass valve setting pressure 40 ~ 80 kPa (0.4 ~ 0.8 kg/cm
2,
5.69 ~ 11.38 psi)----
Cooling:
Radiator core size
Width 117.8 mm (4.6 in) ----
Height 260 mm (10.2 in) ----
Thickness 32 mm (1.26 in) ----
Radiator cap opening pressure110 kPa (1.1 kg/cm
2, 15.6 psi)----
Radiator capacity (total) 0.76 L (0.67 lmp qt, 0.80 US qt) ----
Water pump
Type Single-suction centrifugal pump ----Item Standard Limit

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 - 13
SPECMAINTENANCE SPECIFICATIONS (WR426F)
EC212201
CHASSIS
Item Standard Limit
Steering system:
Steering bearing type Taper roller bearing ----
Front suspension: USA, CDN
AUS, NZ, ZAEUROPE
Front fork travel 300 mm
(11.8 in)←----
Fork spring free length 460 mm
(18.1 in)←455 mm (17.9 in)
Spring rate, STD K = 4.51 N/mm
(0.46 kg/mm,
25.8 lb/in)K = 4.12 N/mm
(0.42 kg/mm,
23.5 lb/in)----
Optional spring/spacer Yes←----
Oil capacity 568 cm
3
(20.0 lmp oz,
19.2 US oz) 578 cm3
(20.3 lmp oz,
19.5 US oz)----
Oil level 135 mm
(5.31 in)125 mm
(4.92 in)----

(From top of outer tube with inner
tube and damper rod fully com-
pressed without spring.)80 ~ 150 mm
(3.15 ~ 5.91 in)←----
Oil grade Suspension oil
“01”←----
Inner tube outer diameter 46 mm (1.81 in)←----
Front fork top end Zero mm
(Zero in)←----
Rear suspension: USA, CDN,
AUS, NZ, ZAEUROPE
Shock absorber travel 132 mm
(5.20 in)←----
Spring free length 260 mm
(10.24 in)←----
Fitting length 246 mm
(9.69 in)247 mm
(9.72 in)----
240.5 ~ 258.5 mm
(9.47 ~ 10.18 in)←----
Spring rate, STD K = 51.0 N/mm
(5.20 kg/mm,
291.2 lb/in)K = 49.0 N/mm
(5.00 kg/mm,
280.0 lb/in)----
Optional spring Yes←----
Enclosed gas pressure 1,000 kPa
(10 kg/cm
2,
142 psi)←----
Swingarm:
Swingarm free play limit
End ---- 1.0 mm (0.04 in)

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SPECMAINTENANCE SPECIFICATIONS (WR400F)
Lubrication system:
Oil filter type Wire mesh type ----
Oil pump type Trochoid type ----
Tip clearance “A”0.12 mm or less
(0.0047 in or less)0.20 mm
(0.008 in)
Tip clearance “B”0.09 ~ 0.17 mm
(0.0035 ~ 0.0067 in)0.24 mm
(0.009 in)
Side clearance 0.03 ~ 0.10 mm
(0.0012 ~ 0.0039 in)0.17 mm
(0.007 in)
Bypass valve setting pressure 40 ~ 80 kPa (0.4 ~ 0.8 kg/cm
2,
5.69 ~ 11.38 psi)----
Cooling:
Radiator core size
Width 117.8 mm (4.6 in) ----
Height 260 mm (10.2 in) ----
Thickness 32 mm (1.26 in) ----
Radiator cap opening pressure110 kPa (1.1 kg/cm
2, 15.6 psi)----
Radiator capacity (total) 0.76 L (0.67 lmp qt, 0.80 US qt) ----
Water pump
Type Single-suction centrifugal pump ----Item Standard Limit

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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

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SPECMAINTENANCE SPECIFICATIONS (WR400F)
EC212201
CHASSIS
Item Standard Limit
Steering system:
Steering bearing type Taper roller bearing ----
Front suspension: AUS EUROPE
Front fork travel 300 mm
(11.8 in)←----
Fork spring free length 460 mm
(18.1 in)←455 mm (17.9 in)
Spring rate, STD K = 4.51 N/mm
(0.46 kg/mm,
25.8 lb/in)K = 4.12 N/mm
(0.42 kg/mm,
23.5 lb/in)----
Optional spring/spacer Yes←----
Oil capacity 568 cm
3
(20.0 lmp oz,
19.2 US oz) 578 cm3
(20.3 lmp oz,
19.5 US oz)----
Oil level 135 mm
(5.31 in)125 mm
(4.92 in)----

(From top of outer tube with inner
tube and damper rod fully com-
pressed without spring.)80 ~ 150 mm
(3.15 ~ 5.91 in)←----
Oil grade Suspension oil
“01”←----
Inner tube outer diameter 46 mm (1.81 in)←----
Front fork top end Zero mm
(Zero in)←----
Rear suspension: AUS EUROPE
Shock absorber travel 132 mm
(5.20 in)←----
Spring free length 260 mm
(10.24 in)←----
Fitting length 246 mm
(9.69 in)247 mm
(9.72 in)----
240.5 ~ 258.5 mm
(9.47 ~ 10.18 in)←----
Spring rate, STD K = 51.0 N/mm
(5.20 kg/mm,
291.2 lb/in)K = 49.0 N/mm
(5.00 kg/mm,
280.0 lb/in)----
Optional spring Yes←----
Enclosed gas pressure 1,000 kPa
(10 kg/cm
2,
142 psi)←----
Swingarm:
Swingarm free play limit
End ---- 1.0 mm (0.04 in)

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