2002 YAMAHA WR 400F maintenance

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SPECMAINTENANCE SPECIFICATIONS (WR426F)
NOTE:
- marked portion shall be checked for torque tightening after break-in or before each race.Part to be tightened Thread size Q’tyTightening torque
Nm m·kg ft·lb
Rear wheel axle and nut M20 × 1.5 1 125 12.5 90
Driven sprocket and wheel hub M8 × 1.25 6 42 4.2 30
Nipple (spoke)—72 3 0.3 2.2
Disc cover and rear brake caliper M6 × 1.0 2 7 0.7 5.1
Protector and rear brake caliper M6 × 1.0 2 7 0.7 5.1
Engine mounting:
Engine bracket and frame M8 × 1.25 7 34 3.4 24
Engine and frame (front) M10 × 1.25 1 69 6.9 50
Engine and frame (upper) M10 × 1.25 1 55 5.5 40
Engine and frame (lower) M10 × 1.25 1 69 6.9 50
Engine guard (left and right) M8 × 1.25 2 23 2.3 17
Pivot shaft and nut M16 × 1.5 1 85 8.5 61
Relay arm and swingarm M14 × 1.5 1 80 8.0 58
Relay arm and connecting rod M14 × 1.5 1 80 8.0 58
Connecting rod and frame M14 × 1.5 1 80 8.0 58
Rear shock absorber and frame M10 × 1.25 1 56 5.6 40
Rear shock absorber and relay arm M10 × 1.25 1 53 5.3 38
Rear frame and frame M8 × 1.25 3 29 2.9 21
Swingarm and brake hose holder M5 × 0.8 4 1 0.1 0.7
Swingarm and patch M4 × 0.7 4 2 0.2 1.4
Drive chain tensioner mounting (upper) M8 × 1.25 1 19 1.9 13
Drive chain tensioner mounting (lower) M8 × 1.25 1 20 2.0 14
Chain support and swingarm M6 × 1.0 3 7 0.7 5.1
Seal guard and swingarm M5 × 0.8 4 6 0.6 4.3
Fuel tank mounting M6 × 1.0 2 10 1.0 7.2
Fuel tank and fuel cock M6 × 1.0 2 7 0.7 5.1
Fuel tank and seat set bracket M6 × 1.0 1 7 0.7 5.1
Fuel tank and hooking screw (fitting band) M6 × 1.0 1 7 0.7 5.1
Fuel tank and fuel tank bracket M6 × 1.0 4 7 0.7 5.1
Seat mounting M8 × 1.25 2 23 2.3 17
Side cover mounting M6 × 1.0 2 7 0.7 5.1
Air scoop and fuel tank M6 × 1.0 4 4 0.4 2.9
Air scoop and radiator panel (lower) M6 × 1.0 2 4 0.4 2.9
Front fender mounting M6 × 1.0 4 7 0.7 5.1
Rear fender and air filter case M6 × 1.0 2 7 0.7 5.1
Rear fender and frame (right) M6 × 1.0 1 10 1.0 7.2
Headlight stay (lower) and under bracket M8 × 1.25 2 7 0.7 5.1
Headlight (left and right) M6 × 1.0 2 10 1.0 7.2
Headlight (lower) M6 × 1.0 1 7 0.7 5.1
Tail light M6 × 1.0 3 4 0.4 2.9
Tail light lead clamp and rear fender M4 × 1.59 2 1 0.1 0.7
Coolant reservoir tank (front) M6 × 1.0 1 7 0.7 5.1
Coolant reservoir tank (rear) M6 × 1.0 1 11 1.1 8.0
Sidestand bracket and frame M10 × 1.25 2 66 6.6 48
Sidestand mounting M10 × 1.25 1 64 6.4 46

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SPECMAINTENANCE SPECIFICATIONS (WR426F)
EC212300
ELECTRICAL
Item Standard Limit
Ignition system:
Advancer type Electrical ----
CDI:
Magneto-model (stator)/manufacturer 5NG-50/YAMAHA ----
Source coil 1 resistance (color) 640 ~ 960 Ω at 20 ˚C (68 ˚F)
(Green – Brown)----
Source coil 2 resistance (color) 464 ~ 696 Ω at 20 ˚C (68 ˚F)
(Green – Pink)----
Lighting coil resistance (color) 0.16 ~ 0.24 Ω at 20 ˚C (68 ˚F)
(Black – Yellow)----
Pickup coil resistance (color) 248 ~ 372 Ω at 20 ˚C (68 ˚F)
(White – Red)----
CDI unit-model/manufacturer 5NG-50/YAMAHA
(For USA)
5NG-60/YAMAHA
(Except for USA)----
----
Ignition coil:
Model/manufacturer 5BE-00/YAMAHA ----
Minimum spark gap 6 mm (0.24 in) ----
Primary winding resistance 0.20 ~ 0.30 Ω at 20 ˚C (68 ˚F) ----
Secondary winding resistance 9.5 ~ 14.3 kΩ at 20 ˚C (68 ˚F) ----
Part to be tightened Thread size Q’tyTightening torque
Nm m·kg ft·lb
Stator M6 × 1.0 3 10 1.0 7.2
Rotor M10 × 1.25 1 48 4.8 35
Ignition coil M6 × 1.0 2 7 0.7 5.1

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SPECMAINTENANCE SPECIFICATIONS (WR400F)
MAINTENANCE SPECIFICATIONS (WR400F)
ENGINE
Item Standard Limit
Cylinder head:
Warp limit ---- 0.05 mm
(0.002 in)
Cylinder:
Bore size 92.00 ~ 92.01 mm
(3.6220 ~ 3.6224 in)----
Out of round limit ---- 0.05 mm
(0.002 in)
Camshaft:
Drive method Chain drive (left) ----
Camshaft cap inside diameter 22.000 ~ 22.021 mm
(0.8661 ~ 0.8670 in)----
Camshaft bearing diameter 21.967 ~ 21.980 mm
(0.8648 ~ 0.8654 in)----
Camshaft-to-cap clearance 0.020 ~ 0.054 mm
(0.0008 ~ 0.0021 in)0.08 mm
(0.003 in)
Cam dimensions
Intake“A”31.7 ~ 31.8 mm
(1.248 ~ 1.252 in)31.6 mm
(1.244 in)
“B”22.95 ~ 23.05 mm
(0.9035 ~ 0.9075 in)22.85 mm
(0.900 in)
Exhaust“A”31.2 ~ 31.3 mm
(1.2283 ~ 1.2323 in)31.1 mm
(1.224 in)
“B”22.95 ~ 23.05 mm
(0.9035 ~ 0.9075 in)22.85 mm
(0.900 in)
Camshaft runout limit ---- 0.03 mm
(0.0012 in)
A
B

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SPECMAINTENANCE SPECIFICATIONS (WR400F)
Cam chain:
Cam chain type/No. of links 92RH2010-120MPX/120 ----
Cam chain adjustment method Automatic ----
Valve, valve seat, valve guide:
Valve clearance (cold) IN 0.10 ~ 0.15 mm
(0.0039 ~ 0.0059 in)----
EX 0.20 ~ 0.25 mm
(0.0079 ~ 0.0098 in)----
Valve dimensions:
“A” head diameter IN 26.9 ~ 27.1 mm
(1.0591 ~ 1.0669 in)----
EX 27.9 ~ 28.1 mm
(1.0984 ~ 1.1063 in)----
“B” face width IN 2.26 mm (0.089 in) ----
EX 2.26 mm (0.089 in) ----
“C” seat width IN 0.9 ~ 1.1 mm
(0.0354 ~ 0.0433 in)1.6 mm
(0.0630 in)
EX 0.9 ~ 1.1 mm
(0.0354 ~ 0.0433 in)1.6 mm
(0.0630 in)
“D” margin thickness IN 1 mm (0.0394 in) 0.85 mm
(0.033 in)
EX 1 mm (0.0394 in) 0.85 mm
(0.033 in)
Stem outside diameter IN 4.475 ~ 4.490 mm
(0.1762 ~ 0.1768 in)4.445 mm
(0.1750 in)
EX 4.965 ~ 4.980 mm
(0.1955 ~ 0.1961 in)4.935 mm
(0.1943 in)
Guide inside diameter IN 4.500 ~ 4.512 mm
(0.1772 ~ 0.1776 in)4.550 mm
(0.1791 in)
EX 5.000 ~ 5.012 mm
(0.1969 ~ 0.1973 in)5.050 mm
(0.1988 in)
Stem-to-guide clearance IN 0.010 ~ 0.037 mm
(0.0004 ~ 0.0015 in)0.08 mm
(0.003 in)
EX 0.020 ~ 0.047 mm
(0.0008 ~ 0.0019 in)0.10 mm
(0.004 in)
Stem runout limit ---- 0.01 mm
(0.0004 in) Item Standard Limit
Head Diameter
B
Face WidthC
Seat Width
D
Margin ThicknessA

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SPECMAINTENANCE SPECIFICATIONS (WR400F)
Valve seat width IN0.9 ~ 1.1 mm
(0.0354 ~ 0.0433 in)1.6 mm
(0.0630 in)
EX 0.9 ~ 1.1 mm
(0.0354 ~ 0.0433 in)1.6 mm
(0.0630 in)
Valve spring:
Free length IN 41.36 mm (1.63 in) 39.3 mm
(1.55 in)
EX 43.60 mm (1.72 in) 41.4 mm
(1.63 in)
Set length (valve closed) IN 32.86 mm (1.29 in) ----
EX 35.38 mm (1.39 in) ----
Compressed pressure
(installed) IN 112.8 ~ 129.8 N
(11.5 ~ 13.2 kg, 25.35 ~ 29.10 lb)----
EX 116.3 ~ 133.9 N
(11.9 ~ 13.7 kg, 26.23 ~ 30.20 lb)----
Tilt limit IN ---- 2.5˚/1.8 mm
(2.5˚/0.071 in)
EX ---- 2.5˚/1.9 mm
(2.5˚/0.075 in)
Direction of winding
(top view) IN Clockwise ----
EX Clockwise ----
Piston:
Piston to cylinder clearance 0.040 ~ 0.065 mm
(0.0016 ~ 0.0026 in)0.1 mm
(0.004 in)
Piston size “D”91.945 ~ 91.960 mm
(3.6199 ~ 3.6205 in)----
Measuring point “H”9 mm (0.354 in) ----
Piston off-set 1 mm (0.0394 in) ----
Piston pin bore inside diameter 18.004 ~ 18.015 mm
(0.7088 ~ 0.7093 in)18.045 mm
(0.7104 in)
Piston pin outside diameter 17.991 ~ 18.000 mm
(0.7083 ~ 0.7087 in)17.971 mm
(0.7075 in) Item Standard Limit
*
H
D

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SPECMAINTENANCE SPECIFICATIONS (WR400F)
Piston rings:
Top ring
Type Barrel ----
Dimensions (B × T) 1.2 × 3.5 mm (0.05 × 0.14 in) ----
End gap (installed) 0.20 ~ 0.35 mm
(0.008 ~ 0.014 in)0.6 mm
(0.024 in)
Side clearance (installed) 0.030 ~ 0.065 mm
(0.0012 ~ 0.0026 in)0.12 mm
(0.005 in)
2nd ring
Type Taper ----
Dimensions (B × T) 1.00 × 3.35 mm (0.04 × 0.13 in) ----
End gap (installed) 0.40 ~ 0.55 mm
(0.016 ~ 0.022 in)0.9 mm
(0.035 in)
Side clearance 0.020 ~ 0.055 mm
(0.0008 ~ 0.0022 in)0.12 mm
(0.005 in)
Oil ring
Dimensions (B × T) 2.0 × 2.9 mm (0.08 × 0.11 in) ----
End gap (installed) 0.2 ~ 0.5 mm (0.01 ~ 0.02 in) ----
Crankshaft:
Crank width “A”61.95 ~ 62.00 mm
(2.439 ~ 2.441 in)----
Runout limit “C”0.03 mm (0.0012 in) 0.05 mm
(0.002 in)
Big end side clearance “D”0.15 ~ 0.45 mm
(0.0059 ~ 0.0177 in)0.50 mm
(0.02 in)
Small end free play “F”0.4 ~ 1.0 mm (0.02 ~ 0.04 in) 2.0 mm
(0.08 in)
Balancer:
Balancer drive method Gear ----
Decompression device:
Type Manual ----
Cable free play 5 ~ 9 mm (0.20 ~ 0.35 in) ----
Air filter oil grade: Engine oil ----Item Standard Limit
T
B
B
T
B
T

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SPECMAINTENANCE SPECIFICATIONS (WR400F)
Clutch:
Friction plate 1 thickness 2.72 ~ 2.88 mm
(0.107 ~ 0.113 in)2.52 mm
(0.099 in)
Inner diameterø112 mm (4.41 in) ----
Quantity 7 ----
Friction plate 2 thickness 2.92 ~ 3.08 mm
(0.115 ~ 0.121 in)2.72 mm
(0.107 in)
Inner diameterø116 mm (4.57 in) ----
Quantity 1 ----
Clutch plate thickness 1.1 ~ 1.3 mm (0.043 ~ 0.051 in) ----
Quantity 7 ----
Warp limit ---- 0.1 mm
(0.004 in)
Clutch spring free length 44 mm (1.73 in) 43 mm
(1.69 in)
Quantity 5 ----
Clutch housing thrust clearance 0.20 ~ 0.45 mm
(0.0079 ~ 0.0177 in)----
Clutch housing radial clearance 0.010 ~ 0.044 mm
(0.0004 ~ 0.0017 in)----
Clutch release method Inner push, cam push ----
Shifter:
Shifter type Cam drum and guide bar ----
Guide bar bending limit ---- 0.05 mm
(0.002 in)
Kick starter:
Type Ratchet type ----
Carburetor:
I. D. mark 5GS6 61 ----
Main jet (M.J) #165 ----
Main air jet (M.A.J) #200 ----
Jet needle-clip position (J.N) OBDRQ-4 ----
Cutaway (C.A) 1.5 ----
Pilot jet (P.J) #42 ----
Pilot air jet (P.A.J) #75 ----
Pilot outlet (P.O)ø0.9 ----
Pilot screw (example) (P.S) 1-1/2 ----
Bypass (B.P)ø1.0 ----
Valve seat size (V.S)ø3.8 ----
Starter jet (G.S) #65 ----
Float height (F.H) 8 mm (0.31 in) ----
Engine idle speed 1,700 ~ 1,900 r/min ----
Intake vacuum 33.3 ~ 38.7 kPa
(250 ~ 290 mmHg, 9.84 ~ 11.42 inHg)---- Item Standard Limit

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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