2008 YAMAHA WR 250F engine

2-8
MAINTENANCE SPECIFICATIONS
Carburetor:USA, CDN, ZA,
AUS, NZ EUROPE
Type/manufacturer FCR-MX37/KEIHIN← ----
I. D. mark 5UME E05UML L0----
Main jet (M.J) #170#160----
Main air jet (M.A.J) #115← ----
Jet needle (J.N) NJRUNNGU----
Cutaway (C.A) 1.5←----
Pilot jet (P.J) #42#45 ----
Pilot air jet (P.A.J) #70← ----
Pilot outlet (P.O) ø0.9←----
Bypass (B.P) ø1.0←----
Valve seat size (V.S) ø3.8←----
Starter jet (G.S) #68← ----
Leak jet (Acc.P) #70← ----
Float height (F.H) 8 mm (0.31 in)← ----
Engine idle speed 1,750–1,950 r/min← ----
Intake vacuum 31.3–36.7 kPa
(235–275 mmHg,
9.25–10.83 inHg) ←
----
Hot starter lever free play 3–6 mm (0.12–0.24
in) ←
----
Lubrication system: Oil filter type Paper type----
Oil pump type Trochoid type----
Tip clearance 0.12 mm or less (0.0047 in or less) 0.20 mm (0.008
in)
Side clearance 0.09–0.17 mm (0.0035–0.0067 in) 0.24 mm (0.009
in)
Housing and rotor clearance 0.03–0.10 mm (0.0012–0.0039 in) 0.17 mm
(0.0067 in)
Cooling: Radiator core sizeWidth 120.2 mm (4.73 in)----
Height 240 mm (9.45 in)----
Thickness 22 mm (0.87 in)----
Radiator cap opening pressure 110 kPa (1.1 kg/cm
2, 15.6 psi)----
Radiator capacity (total) 0.54 L (0.48 Imp qt, 0.57 US qt)----
Water pump Type Single-suction centrifugal pump----
Item
StandardLimit

2-11
TIGHTENING TORQUES
TIGHTENING TORQUES
ENGINE
△- marked portion shall be checked for torque ti ghtening after break-in or before each race.
Normal output 14 V/120 W at 5,000 r/min----
Charging coil resistance (color) 0.288–0.432 Ω at 20 °C (68 °F) (White–
Ground) ----
Lighting coil resistance (color) 0.224–0.336 Ω at 20 °C (68 °F) (Yellow–
Ground) ----
Rectifier/regulator: Regulator type Semiconductor short circuit----
Model/manufacture SH770AA/SHINDENGEN----
Regulated voltage (AC) 12.5–13.5 V----
Regulated voltage (DC) 14.0–15.0 V----
Rectifier capacity (AC) 12 A----
Rectifier capacity (DC) 8 A----
Electric starting system: Type Constant mesh----
Starter motor: Model/manufacturer 5UM01/YAMAHA----
Operation voltage 12 V----
Output 0.35 kW----
Armature coil resistance 0.0189–0.0231 Ω at 20 °C (68 °F) ----
Brush overall length 7 mm (0.28 in)3.5 mm (0.14
in)
Brush quantity 2 pcs.----
Spring force 3.92–5.88 N (400–600 g, 14.1–21.2 oz) ----
Commutator diameter 17.6 mm (0.69 in)16.6 mm (0.65
in)
Mica undercut (depth) 1.5 mm (0.06 in) ----
Starter relay: Model/manufacturer 2768090-A/JIDECO----
Amperage rating 180 A----
Coil winding resistance 4.2–4.6 Ω at 20 °C (68 °F) ----
Starting circui t cut-off relay:
Model/manufacturer ACM33221 M38/MATSUSHITA ----
Coil winding resistance 75.69–92.51 Ω at 20 °C (68 °F) ----
Fuse (amperage×quantity): Main fuse 10 A × 1----
Reserve fuse 10 A × 1----
Item
StandardLimit
Part to be tightened Thread size Q'tyTightening torque
Nm m•kg ft•lb
Spark plug M10S × 1.0 1 13 1.3 9.4
Camshaft cap M6 × 1.0 10 10 1.0 7.2
Cylinder head blind plug screw M12 × 1.0 1 28 2.8 20
Cylinder head (stud bolt) M6 × 1.0 2 7 0.7 5.1

2-14
TIGHTENING TORQUES
Front fork and front fork cap boltM51 × 1.5 2 30 3.0 22
Front fork and base valve M30 × 1.0 2 55 5.5 40
Front fork cap bolt and damper rod M12 × 1.25 2 29 2.9 21
Front fork bleed screw and front fork cap bolt M5 × 0.8 2 1 0.1 0.7
△ Front fork and front fork protector M6 × 1.0 6 7 0.7 5.1
△ Front fork protector and brake hose holder M6 × 1.0 2 7 0.7 5.1
Throttle grip cap M5 × 0.8 2 4 0.4 2.9
△ Front brake master cylinder M6 × 1.0 2 9 0.9 6.5
Brake lever mounting bolt M6 × 1.0 1 6 0.6 4.3
Brake lever mounting nut M6 × 1.0 1 6 0.6 4.3
Brake lever position locknut M6 × 1.0 1 5 0.5 3.6
△ Front brake hose guide and front brake hose guide bracket M5 × 0.8 1 4 0.4 2.9
△ Front brake hose guide and lower bracket M6 × 1.0 1 4 0.4 2.9
Clutch lever holder M5 × 0.8 2 4 0.4 2.9
Clutch lever mounting nut M6 × 1.0 1 4 0.4 2.9
Hot starter lever holder M5 × 0.8 2 4 0.4 2.9
Hot starter lever mounting nut M5 × 0.8 1 2 0.2 1.4
Front brake master cylinder cap M4 × 0.7 2 2 0.2 1.4
△ Front brake hose union bolt M10 × 1.25 2 30 3.0 22
△ Front brake caliper M8 × 1.25 2 23 2.3 17
△ Front brake caliper and brake hose holder M6 × 1.0 1 10 1.0 7.2
Pad pin plug M10 × 1.0 2 3 0.3 2.2
△ Front brake caliper and pad pin M10 × 1.0 1 18 1.8 13
△ Rear brake caliper and pad pin M10 × 1.0 1 18 1.8 13
△ Brake caliper and bleed screw M8 × 1.25 2 6 0.6 4.3
△ Front wheel axle and axle nut M16 × 1.5 1 90 9.0 65
△ Front wheel axle holder M8 × 1.25 4 21 2.1 15
△ Front brake disc M6 × 1.0 6 12 1.2 8.7
△ Rear brake disc M6 × 1.0 6 14 1.4 10
△ Brake pedal M8 × 1.25 1 26 2.6 19
△ Rear brake master cylinder M6 × 1.0 2 10 1.0 7.2
Rear brake master cylinder cap M4 × 0.7 2 2 0.2 1.4
△ Rear brake hose union bolt M10 × 1.25 2 30 3.0 22
△ Rear wheel axle and axle nut M20 × 1.5 1 125 12.5 90
△ Nipple (spoke) —72 3 0.3 2.2
△ Rear wheel sprocket M8 × 1.25 6 50 5.0 36
△ Rear brake disc cover M6 × 1.0 2 10 1.0 7.2
△ Rear brake caliper protector M6 × 1.0 2 7 0.7 5.1
Drive chain puller adjust bolt and locknut M8 × 1.25 2 19 1.9 13
Engine mounting:
△ Engine and engine bracket (front) M10 × 1.25 1 53 5.3 38
△ Engine and frame (lower) M10 × 1.25 1 53 5.3 38
△ Upper engine bracket and frame M8 × 1.25 4 34 3.4 24
△ Lower engine bracket and frame M8 × 1.25 4 34 3.4 24
Part to be tightened
Thread size Q'tyTightening torque
Nm m•kg ft•lb

2-15
TIGHTENING TORQUES
△Engine and engine bracket (upper) M10 × 1.25 1 55 5.5 40
△ Engine guard M6 × 1.0 3 7 0.7 5.1
Regulator M6 × 1.0 2 7 0.7 5.1
△ Pivot shaft and nut M16 × 1.5 1 85 8.5 61
△ Relay arm and swingarm M14 × 1.5 1 70 7.0 50
△ 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 (upper) M8 × 1.25 1 38 3.8 27
△ Rear frame (lower) M8 × 1.25 2 32 3.2 23
△ Swingarm and brake hose holder M5 × 0.8 4 2 0.2 1.4
Swingarm and patch M4 × 0.7 4 2 0.2 1.4
Upper drive chain tensioner M8 × 1.25 1 16 1.6 11
Lower drive chain tensioner M8 × 1.25 1 16 1.6 11
Drive chain support M6 × 1.0 3 7 0.7 5.1
Seal guard and swingarm M5 × 0.8 4 6 0.6 4.3
△ Fuel tank M6 × 1.0 2 9 0.9 6.5
△ Fuel cock M6 × 1.0 2 4 0.4 2.9
Seat set bracket and fuel tank M6 × 1.0 1 7 0.7 5.1
Fuel tank bracket and fuel tank M6 × 1.0 4 7 0.7 5.1
△ Air scoop and fuel tank M6 × 1.0 6 7 0.7 5.1
△ Air scoop and radiator guard (lower) M6 × 1.0 2 6 0.6 4.3
△ Front fender M6 × 1.0 4 7 0.7 5.1
△ Rear fender (front) M6 × 1.0 2 7 0.7 5.1
△ Rear fender (rear) M6 × 1.0 2 11 1.1 8.0
△ Side cover M6 × 1.0 2 7 0.7 5.1
△ Seat M8 × 1.25 2 23 2.3 17
Multi-function display bracket and upper bracket M6 × 1.0 2 7 0.7 5.1
Multi-function display M5 × 0.8 2 4 0.4 2.9
Plate 1 and front fork protector M5 × 0.8 2 4 0.4 2.9
Plate 2 and front fork protector —2 0.5 0.05 0.36
Speed sensor lead holder and lower bracket M6 × 1.0 1 13 1.3 9.4
Speed sensor lead holder and clamp M6 × 1.0 1 7 0.7 5.1
Headlight body and headlight unit —2 1 0.1 0.7
△ Headlight M6 × 1.0 2 7 0.7 5.1
Taillight —3 1 0.1 0.7
Taillight lead clamp and rear fender —3 0.5 0.05 0.36
△ Catch tank (upper) M6 × 1.0 1 16 1.6 11
△ Catch tank (lower) M6 × 1.0 1 7 0.7 5.1
Footrest bracket and frame M10 × 1.25 4 55 5.5 40
Sidestand M10 × 1.25 1 25 2.5 18
Part to be tightened
Thread size Q'tyTightening torque
Nm m•kg ft•lb

2-17
TIGHTENING TORQUES
GENERAL TORQUE
SPECIFICATIONS
This chart specifies torque for stan-
dard fasteners with standard I.S.O.
pitch threads. Torque specifications
for special components or assem-
blies are included in the applicable
sections of this book. To avoid
warpage, tighten multi-fastener as-
semblies in a crisscross fashion, in
progressive stages, until full torque is
reached. Unless otherwise specified,
torque specifications call for clean,
dry threads. Components should be
at room temperature. A. Distance between flats
B. Outside thread diameter
DEFINITION OF UNITS
A
(Nut) B
(Bolt
) TORQUE SPECIFI-
CATION
Nm m•kg ft•lb
10
mm 6 mm 6 0.6 4.3
12
mm 8 mm 15 1.5 11
14
mm 10
mm 30 3.0 22
17
mm 12
mm 55 5.5 40
19
mm 14
mm 85 8.5 61
22
mm 16
mm 130 13 94
Unit
Read Definition Measure
mm
millimeter 10-3 meterLength
cmcentimeter 10-2 meterLength
kgkilogram 103 gramWeight
NNewton 1 kg × m/sec2Force
NmNewton meter N × mTorque
m•kgMeter kilogram m × kg Torque
PaPascalN/m2Pressure
N/mmNewton per millimeter N/mm Spring rate
LLiter—Volume or capacity
cm3Cubic centimeter —Volume or capacity
r/minRevolution per minute —Engine speed

2-25
CABLE ROUTING DIAGRAM
1. Clamp
2. Positive battery lead
3. Battery
4. Negative battery lead
5. Taillight coupler
6. CDI unit coupler (6-pin)
7. CDI unit coupler (3-pin)
8. CDI unit coupler (6-pin)A. Fasten the wire harness, nega-
tive battery lead and starter mo-
tor lead to the upper engine
bracket (left side). Locate the
clamp end facing toward the up-
per side of the frame with the tie
end cut off on the inside of the
frame. B. Fasten the wire harness, nega-
tive battery lead and starter mo-
tor lead to the upper engine
bracket (left side). Locate the
clamp end facing toward the up-
per side of the frame with the tie
end cut off on the inside of the
frame. Clamp the wire harness
and negative lead at the mark-
ing.

2-27
CABLE ROUTING DIAGRAM
1. Throttle cable
2. Clamp
3. Brake hose
4. Clutch cable
5. Hose guide
6. Main switch coupler
7. Wire harness
8. Headlight coupler
9. Hot starter cable
10. Multi-function display bracket
11. Main switch12. Upper bracket
13. Clutch switch coupler
14. Engine stop switch coupler
15. Multi-function display coupler
16. Start switch coupler
17. Speed sensor coupler
18. Speed sensor lead
A. Fasten the star
t switch lead to
the handlebar with the plastic
bands. B. Fasten the engine stop switch
lead and clutch switch lead to
the handlebar with the plastic
bands.
C. Pass the brake hose through
the hose guides.
D. Secure the coupler by inserting it into the multi-function display
bracket.

3-1
MAINTENANCE INTERVALS
REGULAR INSPECTION AND ADJUSTMENTS
MAINTENANCE INTERVALS
The following schedule is intended as a general guide to maint enance 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 maintaini ng and lubricating your machine, consult your Yamaha dealer.
ItemAfter
break- in Every
race
Every third
(or 500
km) Every
fifth (or 1,000
km)
As re-
quired Remarks
ENGINE OIL Replace ●●
VALVES Check the valve clearances ●● The engine must be cold.
Inspect ●Check the valve seats and valve
stems for wear.
Replace ●
VALVE SPRINGS Inspect ●Check the free length and the tilt.
Replace ●
VALVE LIFTERS Inspect ●Check for scratches and wear.
Replace ●
CAMSHAFTS Inspect the camshaft surface.
Inspect ●Inspect the decompression system.
Replace ●
CAMSHAFT SPROCKETS Inspect ●Check for wear on the teeth and for
damage.
Replace ●
PISTON Inspect ●●Inspect crack.
Clean ●Inspect carbon deposits and eliminate
them.
Replace ●
PISTON RING Inspect ●Check ring end gap.
Replace ●●
PISTON PIN Inspect ●
Replace ●
CYLINDER HEAD Inspect carbon deposits and eliminate
them.
Inspect and clean ●Change gasket.
CYLINDER Inspect and clean ●Inspect score marks.
Replace ●Inspect wear.