2014 YAMAHA YZ250F Owners Manual

ENGINE SPECIFICATIONS
2-6
Crankshaft
Width A 55.95–56.00 mm (2.203–2.205 in)
Runout limit C 0.030 mm (0.0012 in)
Big end side clearance D 0.150–0.450 mm (0.0059–0.0177 in)
Balancer
Balancer drive method Gear
Clutch
Clutch type Wet, multiple-disc
Clutch release method Inner push, cam push
Clutch lever free play 7.0–12.0 mm (0.28–0.47 in)
Friction plate thickness 2.90–3.10 mm (0.114–0.122 in)
Wear limit 2.80 mm (0.110 in)
Plate quantity 9 pcs
Clutch plate thickness 1.10–1.30 mm (0.043–0.051 in)
Plate quantity 8 pcs
Warpage limit 0.10 mm (0.0039 in)
Clutch spring free length 45.00 mm (1.77 in)
Limit 44.00 mm (1.73 in)
Spring quantity 5 pcs
Push rod bending limit 0.10 mm (0.0039 in)
Transmission
Transmission type Constant mesh 5-speed
Primary reduction system Spur gear
Primary reduction ratio 3.353 (57/17)
Final drive Chain
Secondary reduction ratio 3.846 (50/13)
Operation Left foot operation
Gear ratio
1st 2.143 (30/14)
2nd 1.750 (28/16)
3rd 1.444 (26/18)
4th 1.222 (22/18)
5th 1.042 (25/24)
Shifting mechanism
Shift mechanism type Shift drum and guide bar
Shift fork guide bar bending limit 0.050 mm (0.0020 in)
Shift fork thickness 4.85 mm (0.1909 in)
Decompression device
Device type Auto decomp
CC
D
A

ENGINE SPECIFICATIONS
2-7
Air filter
Air filter element Wet element
Air filter oil grade Foam air-filter oil
Fuel pump
Pump type Electrical
Fuel injector
Model/quantity 30NA-FZ31/1
Resistance 12 
Throttle body
Type/quantity 30RA-A13M/1
ID mark 1SM1 00
Fuel pressure 324.0 kPa (3.24 kgf/cm
2, 47.0 psi)
Throttle position sensor
Resistance 6.30 k
Output voltage (at idle) 0.5 V
Fuel injection sensor
Crankshaft position sensor resistance 228–342 
Intake air pressure sensor output voltage 3.57–3.71 V at 101.3 kPa
Intake air temperature sensor resistance 290–390  at 80 °C (176 °F)
Coolant temperature sensor resistance 2.51–2.78 k at 20 °C (68 °F)
210–221  at 100 °C (212 °F)
Idling condition
Engine idling speed 1900–2100 r/min
Water temperature 70–80 °C (158–176 °F)
Oil temperature 55–65 °C (131–149 °F)
Throttle grip free play 3.0–5.0 mm (0.12–0.20 in)

CHASSIS SPECIFICATIONS
2-8
EAS1SM1054
CHASSIS SPECIFICATIONS
Chassis
Frame type Semi double cradle
Caster angle 27.08 ° (USA) (CAN) (AUS) (NZL) (ZAF)
26.83 ° (EUR)
27.00 ° (JPN)
Trail 118 mm (4.6 in) (USA) (CAN) (EUR)
119 mm (4.7 in) (JPN) (AUS) (NZL) (ZAF)
Front wheel
Wheel type Spoke wheel
Rim size 21  1.60
Rim material Aluminum
Wheel travel 310.0 mm (12.20 in)
Radial wheel runout limit 2.0 mm (0.08 in)
Lateral wheel runout limit 2.0 mm (0.08 in)
Wheel axle bending limit 0.50 mm (0.02 in)
Rear wheel
Wheel type Spoke wheel
Rim size 19  1.85
Rim material Aluminum
Wheel travel 315.0 mm (12.40 in)
Radial wheel runout limit 2.0 mm (0.08 in)
Lateral wheel runout limit 2.0 mm (0.08 in)
Wheel axle bending limit 0.50 mm (0.02 in)
Front tire
Type With tube
Size 80/100-21 51M
Manufacturer/model BRIDGESTONE/M403A (USA) (CAN) (AUS)
(NZL) (ZAF)
PIRELLI/MID SOFT 32 (EUR)
DUNLOP/MX51FA (JPN)
Rear tire
Type With tube
Size 100/90-19 57M
Manufacturer/model BRIDGESTONE/M404 (USA) (CAN) (AUS)
(NZL) (ZAF)
PIRELLI/MID SOFT 32 (EUR)
DUNLOP/MX51G (JPN)
Tire air pressure (measured on cold tires)
Front 100 kPa (1.00 kgf/cm2, 15 psi)
Rear 100 kPa (1.00 kgf/cm2, 15 psi)
Front brake
Type Single disc brake
Operation Right hand operation
Front disc brake
Disc outside diameter  thickness 250.0  3.0 mm (9.84  0.12 in)

CHASSIS SPECIFICATIONS
2-9
Brake disc thickness limit 2.5 mm (0.10 in)
Brake pad lining thickness (inner) 4.4 mm (0.17 in)
Limit 1.0 mm (0.04 in)
Brake pad lining thickness (outer) 4.4 mm (0.17 in)
Limit 1.0 mm (0.04 in)
Master cylinder inside diameter 9.52 mm (0.37 in)
Caliper cylinder inside diameter 22.65 mm  2 (0.89 in  2)
Recommended brake fluid DOT 4
Rear brake
Type Single disc brake
Operation Right foot operation
Rear disc brake
Disc outside diameter  thickness 245.0  4.0 mm (9.65  0.16 in)
Brake disc thickness limit 3.5 mm (0.14 in)
Brake disc deflection limit 0.15 mm (0.0059 in)
Brake pad lining thickness (inner) 6.4 mm (0.25 in)
Limit 1.0 mm (0.04 in)
Brake pad lining thickness (outer) 6.4 mm (0.25 in)
Limit 1.0 mm (0.04 in)
Master cylinder inside diameter 11.0 mm (0.43 in)
Caliper cylinder inside diameter 25.40 mm  1 (1.00 in  1)
Recommended fluid DOT 4
Steering
Steering bearing type Taper roller bearing
Center to lock angle (left) 43.0 °
Center to lock angle (right) 43.0 °
Front suspension
Type Telescopic fork
Spring/shock absorber type Coil spring/oil damper
Front fork travel 310.0 mm (12.20 in)
Fork spring free length 497.0 mm (19.57 in)
Limit 492.0 mm (19.37 in)
Installed length 497.0 mm (19.57 in)
Spring rate K1 4.70 N/mm (0.48 kgf/mm, 26.84 lbf/in) (USA)
(CAN)
4.60 N/mm (0.47 kgf/mm, 26.27 lbf/in) (EUR)
(JPN) (AUS) (NZL) (ZAF)
Spring stroke K1 0.0–310.0 mm (0.00–12.20 in)
Inner tube outer diameter 48.0 mm (1.89 in)
Inner tube bending limit 0.2 mm (0.01 in)
Optional spring available Yes
Recommended oil Suspension oil S1
Standard oil amount 526.0 cm
3 (17.78 US oz, 18.55 Imp.oz) (USA)
(CAN)
551.0 cm
3 (18.63 US oz, 19.43 Imp.oz) (EUR)
(JPN) (AUS) (NZL) (ZAF)
Rebound damping adjusting positions
* Position in which the adjuster is turned in finger tight
Minimum 20 click (s) out*
Standard 9 click (s) out* (USA) (CAN)
8 click (s) out* (EUR) (JPN) (AUS) (NZL) (ZAF)
Maximum (hard) Fully turned in

CHASSIS SPECIFICATIONS
2-10
Compression damping adjusting positions * Position in which the adjuster is turned in finger tight
Minimum 20 click (s) out*
Standard 8 click (s) out* (USA) (CAN) 6 click (s) out* (EUR) (JPN) (AUS) (NZL) (ZAF)
Maximum (hard) Fully turned in
Rear suspension Type Swingarm (link suspension)
Spring/shock absorber type Coil spring/gas-oil damper
Rear shock absorber assembly travel 132.0 mm (5.20 in)
Spring free length 275.0 mm (10.83 in)
Spring rate K1 56.00 N/mm (5.71 kgf/mm, 319.76 lbf/in) (USA)
(CAN)
54.00 N/mm (5.51 kgf/mm, 308.34 lbf/in) (EUR)
(JPN) (AUS) (NZL) (ZAF)
Spring stroke K1 0.0–150.0 mm (0.00–5.91 in)
Optional spring available Yes
Enclosed gas/air pressure (STD) 980 kPa (9.8 kgf/cm
2, 139.4 psi)
Spring installed length Minimum Position in which the spring is turned in 1.5 mm
(0.06 in) from its free length.
Standard Position in which the spring is turned in 10 mm
(0.39 in) from its free length.
Maximum Position in which the spring is turned in 18 mm
(0.71 in) from its free length.
Rebound damping adjusting positions
* Position in which the adjuster is turned in finger tight
Minimum 30 click (s) out*
Standard 14 click (s) out*
Maximum Fully turned in
Compression damping adjusting positions (for fast compression damping)
* Position in which the adjuster is turned in finger tight
Minimum 2 turn (s) out*
Standard 1-1/3 turn (s) out* (USA) (CAN)
1-1/8 turn (s) out* (EUR) (JPN) (AUS) (NZL)
(ZAF)
Maximum Fully turned in
Compression damping adjusting positions
(for slow compression damping)* Position in which the adjuster is turned in finger tight
Minimum 20 click (s) out*
Standard 10 click (s) out*
Maximum Fully turned in
Swingarm
Swingarm end free play limit (radial) 1.0 mm (0.04 in)
Swingarm end free play limit (axial) 0.2–0.9 mm (0.01–0.04 in)
Drive chain
Type/manufacturer 520DMA2-SDH/DAIDO
Number of links 114
Drive chain slack 50–60 mm (1.97–2.36 in)
15-link length limit 242.9 mm (9.56 in)

ELECTRICAL SPECIFICATIONS
2-11
EAS1SM1055
ELECTRICAL SPECIFICATIONS
Voltage
System voltage 12 V
Ignition system
Ignition system TCI
Advancer type Digital
Ignition timing (B.T.D.C.) 10.0 ° at 2000 r/min
Engine control unit
Model/manufacturer 1SM0/YAMAHA (USA) (CAN)
1SM1/YAMAHA (EUR) (AUS) (NZL) (ZAF)
1SM2/YAMAHA (JPN)
Ignition coil
Minimum ignition spark gap 6.0 mm (0.24 in)
Primary coil resistance 2.16–2.64 
Secondary coil resistance 8.64–12.96 k
AC magneto
Standard output 14.0 V, 95 W at 5000 r/min
Stator coil resistance 0.624–0.936 
Rectifier/regulator
Regulator type Semi conductor-short circuit
No load regulated voltage 14.1–14.9 V
Rectifier capacity (DC) 23.0 A

TIGHTENING TORQUES
2-12
EAS20320
TIGHTENING TORQUES
EAS1SM1056GENERAL TIGHTENING TORQUE SPECIFI-
CATIONS
This chart specifies tightening torques for stan-
dard fasteners with a standard ISO thread
pitch. Tightening torque specifications for spe-
cial components or assemblies are provided for
each chapter of this manual. To avoid warpage,
tighten multi-fastener assemblies in a criss-
cross pattern and progressive stages until the
specified tightening torque is reached. Unless
otherwise specified, tightening torque specifi-
cations require clean, dry threads. Compo-
nents should be at room temperature.
A. Distance between flats
B. Outside thread diameter
A (nut)B
(bolt)General tightening
torques
Nm m·kgf ft·lbf
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 13.0 94

TIGHTENING TORQUES
2-13
EAS1SM1057ENGINE TIGHTENING TORQUES
TIP
- marked portion shall be checked for torque tightening after break-in or before each race.
ITEMThread
sizeQ’ty TIGHTENING TORQUES Remarks
Camshaft cap bolt
M6 8 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Cylinder head blind plug
M12 1 28 Nm (2.8 m·kgf, 20 ft·lbf)
Spark plug
M10 1 13 Nm (1.3 m·kgf, 9.4 ft·lbf)
Cylinder head stud bolt
M6 2 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Cylinder head stud bolt (exhaust
pipe)M8 2 15 Nm (1.5 m·kgf, 11 ft·lbf)
Cylinder head bolts
M9 4 33 Nm (3.3 m·kgf, 24 ft·lbf)
Cylinder head nuts
M6 2 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Cylinder head cover bolt
M6 2 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Cylinder bolt
M6 1 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Oil pressure check bolt
M6 1 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Balancer weight plate screw
M6 2 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Balancer driven gear nut M14 1 50 Nm (5.0 m·kgf, 36 ft·lbf)
Balancer nut M10 1 40 Nm (4.0 m·kgf, 29 ft·lbf)
Timing chain guide stopper plate
(exhaust side)M6 1 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Timing chain tensioner cap bolt
M6 1 6 Nm (0.6 m·kgf, 4.3 ft·lbf)
Timing chain tensioner bolt
M6 2 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Coolant drain bolt
M6 1 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Radiator hose clamp screw
M6 8 1.5 Nm (0.15 m·kgf, 1.1 ft·lbf)
Radiator bolt
M6 4 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Radiator pipe bolt
M6 1 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Radiator pipe joint bolt
M6 1 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Water pump housing cover bolt
M6 4 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Oil pump bolt
M5 2 5 Nm (0.5 m·kgf, 3.6 ft·lbf)
Oil pump cover screw
M4 1 2.0 Nm (0.20 m·kgf, 1.4 ft·lbf)
Oil strainer bolt
M6 1 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Throttle cable cover bolt
M5 1 3.5 Nm (0.35 m·kgf, 2.5 ft·lbf)
Throttle body joint bolt
M6 2 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Throttle body joint clamp bolt
M5 1 3.0 Nm (0.30 m·kgf, 2.2 ft·lbf)
Air filter joint clamp bolt
M4 1 3.5 Nm (0.35 m·kgf, 2.5 ft·lbf)
Air filter case bolt M6 3 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Air filter bolt M6 1 2.0 Nm (0.20 m·kgf, 1.4 ft·lbf)
Air filter case cover bolt
M6 3 6 Nm (0.6 m·kgf, 4.3 ft·lbf)
LT
M
LT
LT
LT