2015 YAMAHA WR 250F sensor

FEATURES
1-6
EAS20170
FEATURES
EAS2GB2014OUTLINE OF THE FI SYSTEM
The main function of a fuel supply system is to provide fuel to the combustion chamber at the opti-
mum air-fuel ratio in accordance with the engine operating conditions and the atmospheric tempera-
ture. In the conventional carburetor system, the air-fuel ratio of the mixture to be supplied to the
combustion chamber is determined by the amount of intake air and fuel that is measured on the basis
of the jets to be used in the carburetor.
Despite the same amount of intake air, the fuel amount requirement varies with the engine operating
conditions (acceleration, deceleration, and operation under a heavy load). The carburetor that mea-
sures fuel through the use of jets are provided with various auxiliary devices, so that the optimum air
fuel ratio can be obtained to accommodate frequent changes in the operating conditions of the en-
gine. This model has adopted an electronically controlled fuel injection (FI) system, in place of the
conventional carburetor system. This system can obtain the optimum air-fuel ratio required by the
engine at all times by using a microprocessor that regulates the fuel injection amount according to
the engine operating conditions detected by various sensors.
1. Fuel injector
2. Throttle position sensor
3. Intake air pressure sensor
4. Engine trouble warning light
5. Intake air temperature sensor
6. ECU
7. Fuel pump
8. Battery
9. Lean angle sensor
10.Crankshaft position sensor
11.Coolant temperature sensor
12.Ignition coil
13.Speed sensor
748
9 10 116 5 123
12
13

FEATURES
1-7
EAS2GB2015FI SYSTEM
The fuel pump delivers fuel to the fuel injector via the fuel filter. The pressure regulator maintains the
fuel pressure that is applied to the fuel injector at only 324 kPa (3.24 kgf/cm
2, 47.0 psi). Accordingly,
when the energizing signal from the ECU energizes the fuel injector, the fuel passage opens, causing
the fuel to be injected into the intake manifold only during the time the passage remains open. There-
fore, the longer the length of time the fuel injector is energized (injection duration), the greater the
volume of fuel that is supplied. Conversely, the shorter the length of time the fuel injector is energized
(injection duration), the lesser the volume of fuel that is supplied.
The injection duration and the injection timing are controlled by the ECU. Signals input from the throt-
tle position sensor, the coolant temperature sensor, the crankshaft position sensor, the intake air
pressure sensor, and the intake air temperature sensor enable the ECU to determine the injection
duration. The injection timing is determined through the signals from the crankshaft position sensor.
As a result, the volume of fuel that is required by the engine can be supplied at all times in accordance
with the driving conditions.
1. Fuel pump
2. Fuel injector
3. ECU
4. Throttle position sensor
5. Coolant temperature sensor
6. Crankshaft position sensor
7. Intake air pressure sensor
8. Throttle body
9. Intake air temperature sensor
10.Air filter case
A. Fuel system
B. Intake system
C. Control system
1
23
5
6 7
8 9 10A
BC
4

SPECIAL TOOLS
1-17
Pocket tester
90890-03112
Analog pocket tester
YU-03112-CThis tool is used to measure
the voltage, current, and re-
sistance of electrical compo-
nents.
Timing light
90890-03141
Timing light
YU-03141This tool is used to measure
the ignition timing.
Pressure gauge
90890-03153
Pressure gauge
YU-03153This tool is used to measure
the fuel pressure.
Fuel pressure adapter
90890-03186
Fuel pressure adapter
YM-03186This tool is used to mount the
pressure gauge.
Test harness S– pressure
sensor (3P)
90890-03207
Test harness S– pressure
sensor (3P)
YU-03207This tool is used to check the
throttle position sensor input
voltage.
Test harness– lean angle
sensor (6P)
90890-03209
Test harness– lean angle
sensor (6P)This tool is used to check the
lean angle sensor output volt-
age.
FI diagnostic tool sub–lead
90890-03212
FI diagnostic tool sub–lead
YU-03212This tool is used to connect
the Yamaha diagnostic tool
to a battery.
Test harness– speed sensor
5TJ (3P)
90890-03228
Test harness– speed sensor
5TJ (3P)
YU-03228This tool is used to check the
speed sensor output voltage.
Yamaha diagnostic tool
90890-03231
Yamaha diagnostic tool (US)
90890-03234This tool is used to check er-
ror codes or carry out self-di-
agnosis. Tool name/Part number How to use Illustration

ENGINE SPECIFICATIONS
2-7
Fuel pump
Pump type Electrical
Fuel injector
Model/quantity 30NA-FZ31/1
Resistance 12 
Throttle body
Type/quantity 30RA-A95R/1
ID mark 2GB1 00
Fuel line pressure at idling 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  (Gy–B)
Intake air pressure sensor output voltage 3.61–3.67 V at 101.3 kPa (3.61–3.67 V at 1.01
kgf/cm
2, 3.61–3.67 V at 14.7 psi)
Intake air temperature sensor resistance 290–390  at 80 °C (290–390  176 °F)
Coolant temperature sensor resistance 2.51–2.78 k at 20 °C (2.51–2.78 k at 68 °F)
210–221  at 100 °C (210–221  at 212 °F)
Idling condition
Engine idling speed 1900–2100 r/min
CO% 3.0–4.0 % (USA) (CAN)
Intake vacuum 25.3–29.3 kPa (190–220 mmHg, 7.5–8.7 inHg)
(USA) (CAN)
Water temperature 70.0–90.0 °C (158.00–194.00 °F)
Oil temperature 70.0–80.0 °C (158.00–176.00 °F)
Throttle grip free play 3.0–5.0 mm (0.12–0.20 in)

TIGHTENING TORQUES
2-16
TIP
Exhaust pipe nut
First temporarily tighten nuts to 13 Nm (1.3 m·kgf, 9.4 ft·lbf). Then retighten them to 20 Nm (2.0 m·kgf,
14 ft·lbf).Clutch boss nut M16 1 75 Nm (7.5 m·kgf, 54 ft·lbf)Use a
lock
washer.
Drive sprocket nut M18 1 75 Nm (7.5 m·kgf, 54 ft·lbf)Use a
lock
washer.
Segment
M8 1 30 Nm (3.0 m·kgf, 22 ft·lbf)
Shift guide bolt
M6 2 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Stopper lever bolt
M6 1 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Shift pedal bolt M6 1 12 Nm (1.2 m·kgf, 8.7 ft·lbf)
Rotor nut
M12 1 65 Nm (6.5 m·kgf, 47 ft·lbf)
Stator screw
M5 2 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Crankshaft position sensor bolt
M6 2 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Damper assembly cover bolt
M6 2 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Starter clutch bolt
M6 6 16 Nm (1.6 m·kgf, 12 ft·lbf)
Starter motor bolt
M6 1 12 Nm (1.2 m·kgf, 8.7 ft·lbf)
Coolant temperature sensor
M10 1 16 Nm (1.6 m·kgf, 12 ft·lbf)
Neutral switch bolt
M5 2 3.5 Nm (0.35 m·kgf, 2.5 ft·lbf)
Intake air temperature sensor screw
M5 1 1.5 Nm (0.15 m·kgf, 1.1 ft·lbf)
Rectifier/regulator bolt
M6 2 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
ECU bolt
M5 2 3.8 Nm (0.38 m·kgf, 2.8 ft·lbf)
Ignition coil bolt
M6 2 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Throttle position sensor screw
M5 2 3.4 Nm (0.34 m·kgf, 2.5 ft·lbf)
Intake air pressure sensor screw
M6 1 5 Nm (0.5 m·kgf, 3.6 ft·lbf) ITEMThread
sizeQ’ty TIGHTENING TORQUES Remarks
LT
LT
LT
LT
LT
LT

TIGHTENING TORQUES
2-19
Drive chain tensioner bolt (lower
side)M8 1 16 Nm (1.6 m·kgf, 12 ft·lbf)
Drive chain support bolt M6 1 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Drive chain support nut M6 2 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Drive chain guide bolt M5 3 4.0 Nm (0.40 m·kgf, 2.9 ft·lbf)
Rear frame and left cover bolt M6 2 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Fuel tank bolt (front side) M6 2 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Fuel tank bolt (rear side) M6 1 9 Nm (0.9 m·kgf, 6.5 ft·lbf)
Fuel tank bracket bolt (front side) M6 4 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Fuel tank bracket bolt (rear side) M6 2 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Fuel pump bolt M5 6 4.0 Nm (0.40 m·kgf, 2.9 ft·lbf)
Fuel sender screw M6 2 4.0 Nm (0.40 m·kgf, 2.9 ft·lbf)
Fuel inlet pipe screw M5 2 3.4 Nm (0.34 m·kgf, 2.5 ft·lbf)
Fuel tank cap cover bolt M6 2 4.0 Nm (0.40 m·kgf, 2.9 ft·lbf)
Seat set bracket and fuel tank screw M6 1 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Seat bolt M8 2 22 Nm (2.2 m·kgf, 16 ft·lbf)
Left side cover bolt M6 1 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Right side cover bolt M6 2 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Frame and air scoop bolt M6 2 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Fuel tank and air scoop bolt M6 2 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Radiator guard and air scoop bolt M6 4 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Front fender bolt M6 4 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Rear fender bolt (front side) M6 4 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Rear fender bolt (rear side) M6 2 16 Nm (1.6 m·kgf, 12 ft·lbf)
Mud flap screw — 2 1.3 Nm (0.13 m·kgf, 0.94 ft·lbf)
Headlight body and headlight stay
boltM6 2 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Multi-function meter nut M5 2 3.8 Nm (0.38 m·kgf, 2.8 ft·lbf)
Multi-function meter bracket bolt M6 1 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Front brake hose guide and head-
light stay boltM5 1 3.8 Nm (0.38 m·kgf, 2.8 ft·lbf)
Plate 1 and front fork protector bolt M5 2 3.8 Nm (0.38 m·kgf, 2.8 ft·lbf)
Plate 2 and front fork protector
screw— 2 0.5 Nm (0.05 m·kgf, 0.36 ft·lbf)
Speed sensor lead holder and
speed sensor lead bracket boltM6 1 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Speed sensor lead bracket and low-
er bracket boltM6 1 13 Nm (1.3 m·kgf, 9.4 ft·lbf)
Starter relay and positive battery
lead boltM6 1 3.5 Nm (0.35 m·kgf, 2.5 ft·lbf) ITEMThread
sizeQ’ty TIGHTENING TORQUES Remarks

TIGHTENING TORQUES
2-20
TIP
Lower ring nut
1. First, tighten the lower ring nut approximately 38 Nm (3.8 m·kgf, 27 ft·lbf) by using the steering nut
wrench, then loosen the lower ring nut one turn.
2. Retighten the lower ring nut 7 Nm (0.7 m·kgf, 5.1 ft·lbf).Starter relay and starter motor lead
boltM6 1 3.5 Nm (0.35 m·kgf, 2.5 ft·lbf)
Lean angle sensor bolt M4 2 3.8 Nm (0.38 m·kgf, 2.8 ft·lbf)
Taillight assembly screw — 3 1.1 Nm (0.11 m·kgf, 0.80 ft·lbf)
Taillight lead clamp and rear fender — 3 0.5 Nm (0.05 m·kgf, 0.36 ft·lbf)
Battery bracket bolt M6 4 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Frame and battery negative lead
boltM6 1 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Rear fender and relay bracket screw — 2 1.1 Nm (0.11 m·kgf, 0.80 ft·lbf)
Front reflector nut (For Canada) M6 2 3.8 Nm (0.38 m·kgf, 2.8 ft·lbf)
Rear reflector nut (For Canada) M5 3 1.8 Nm (0.18 m·kgf, 1.3 ft·lbf)ITEMThread
sizeQ’ty TIGHTENING TORQUES Remarks

LUBRICATION POINTS AND LUBRICANT TYPES
2-22
EAS2GB2072CHASSISStarter idle gear inner surface, thrust surfaces
Starter clutch drive gear inner surface, thrust surfaces
Cylinder head cover gasketThree bond
No.1215®
Crankcase mating surfaceThree bond
No.1215®
Stator assembly lead grommetThree bond
No.1215®
Lubrication point Lubricant types
Upper bearings (steering head)
Upper bearings and bearing race cover (steering head)
Lower bearings and oil seal lip (steering head)
Steering stem threads and nut contacting surface
Pivot shaft bearing
Swingarm pivot portion (collar side surface and thrust bearing)
Swingarm pivot portion (collar outer surface)
Swingarm pivot portion (oil seal lip)
Pivot shaft outer surface
Relay arm bearing and oil seal lip
Relay arm thrust washer surface (both sides)
Relay arm collar outer surface and bolt outer surface
Relay arm bolt threads (swingarm side)
Connecting arm bearing and oil seal lip
Connecting arm collar outer surface and bolt outer surface
Rear shock absorber assembly collar outer surface and dust seal lip (upper
side)
Rear shock absorber assembly bearing and dust seal lip (lower side)
Brake pedal pivot portion (O-ring and bolt outer surface)
Front wheel oil seal lip
Front wheel axle outer surface
Speed sensor oil seal lip
Rear wheel oil seal lip
Rear wheel axle outer surface
Sidestand pivot portion and collar outer surface
Brake lever contacting portion (front brake master cylinder)
Front brake lever bolt outer surface
Clutch lever sliding surface and bolt outer surface
Clutch lever adjuster rubber lip
Clutch cable end (clutch lever side)Lubrication point Lubricant types
E
E
LS
LS
LS
LS
M
M
M
M
M
M
M
M
M
M
M
M
M
LS
LS
LS
LS
LS
LS
LS
S
S
LS
LS
LS