fuel pressure YAMAHA WR 250F 2017 Owners Manual

SPECIAL TOOLS
1-15
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)
YU-03209This 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

MAINTENANCE AFTER BREAK-IN
1-33
EAS2GBB055
MAINTENANCE AFTER BREAK-IN
After a break-in, perform careful maintenance
to get ready for the next practice or race.
Refer to “PRE-OPERATION INSPECTION
AND MAINTENANCE” on page 3-9.
EAS2GBB056MAJOR MAINTENANCE
1. For the engine
• Leaks around the engine
Check for pressure leaks from the cylinder
head or the cylinder, oil leaks from the
crankcase or the case cover, leaks from the
coolant system, and other leaks.
• Check that the valve, the cylinder head, the
cylinder, the piston, and the piston ring fit
one another, and that contact between the
valve and the cylinder head, and that be-
tween the cylinder and the piston are cor-
rect.
• Engine oil change
Drain the oil, and check for dirt and foreign
materials such as metal chips. (If any foreign
material is mixed, disassemble and check
the crankcase.)
Pour the specified amount of the recom-
mended oil.
• AC magneto
Check for looseness in mounted areas of
the rotor and the stator.
Check that the connector is not being dis-
connected.
• Silencer
Check the main body and stay for cracks.
Check for leaks.
• Mounting bolts and nuts
Check for looseness in mounted areas of
parts, as well as engine mounting bolts and
engine brackets.
2. For the chassis
• Check welds and mounted areas of the
frame, the swingarm, the link, the bracket,
and so on, for looseness and cracks.
• Wheel (s)
Check the wheel for runout. Check the
spoke for looseness.
• Brake(s)
Check the brake disc mounting bolt for
looseness.
Check that the reservoir contains the speci-
fied amount of brake fluid. Check for leaks.• Cable
Grease and adjust cables.
•Drive chain
Lubricate the drive chain and adjust its ten-
sion.
• Fuel tank
Clean the inside of the fuel tank. Check for
leaks.
• Suspension
Check for oil leaks in the front fork or the rear
shock absorber. Check that the mounted
conditions are good.
• Sprocket
Check for looseness in the sprocket mount-
ed on the rear wheel.
• Mounting bolts and nuts
Check mounted areas for looseness.
ECA
NOTICE
After a break-in or before each race, always
check the points shown in “TORQUE-
CHECK POINTS” for tightening torques and
retighten them. (Refer to “TORQUE-CHECK
POINTS” on page 1-34.)
• Greasing and oiling
Always grease or oil the specified points.

MOTORCYCLE CARE AND STORAGE
1-36
EAS2GBB058
MOTORCYCLE CARE AND STOR-
AGE
EAS2GBB059CARE
While the open design of a motorcycle reveals
the attractiveness of the technology, it also
makes it more vulnerable. Rust and corrosion
can develop even if high-quality components
are used. A rusty exhaust pipe may go unno-
ticed on a car, however, it detracts from the
overall appearance of a motorcycle. Frequent
and proper care does not only comply with the
terms of the warranty, but it will also keep your
motorcycle looking good, extend its life and op-
timize its performance.
Before cleaning
1. Cover the muffler outlet with a plastic bag af-
ter the engine has cooled down.
2. Make sure that all caps and covers as well
as all electrical couplers and connectors, in-
cluding the spark plug cap, are tightly in-
stalled.
3. Remove extremely stubborn dirt, like oil
burnt onto the crankcase, with a degreasing
agent and a brush, but never apply such
products onto seals, gaskets, sprockets, the
drive chain and wheel axles. Always rinse
the dirt and degreaser off with water.
Cleaning
ECA
NOTICE
• Avoid using strong acidic wheel cleaners,
especially on spoked wheels. If such prod-
ucts are used on hard-to-remove dirt, do
not leave the cleaner on the affected area
any longer than instructed. Also, thor-
oughly rinse the area off with water, imme-
diately dry it, and then apply a corrosion
protection spray.
• Improper cleaning can damage plastic
parts (such as cowlings, panels, wind-
shields, headlight lenses, meter lenses,
etc.) and the mufflers. Use only a soft,
clean cloth or sponge with water to clean
plastic. However, if the plastic parts can-
not be thoroughly cleaned with water, di-
luted mild detergent with water may be
used. Be sure to rinse off any detergent
residue using plenty of water, as it is
harmful to plastic parts.• Do not use any harsh chemical products
on plastic parts. Be sure to avoid using
cloths or sponges which have been in con-
tact with strong or abrasive cleaning prod-
ucts, solvent or thinner, fuel (gasoline),
rust removers or inhibitors, brake fluid,
antifreeze or electrolyte.
• Do not use high-pressure washers or
steam-jet cleaners since they cause water
seepage and deterioration in the following
areas: seals (of wheel and swingarm bear-
ings, fork and brakes), electric compo-
nents (couplers, connectors, instruments,
switches and lights), breather hoses and
vents.
• For motorcycles equipped with a wind-
shield: Do not use strong cleaners or hard
sponges as they will cause dulling or
scratching. Some cleaning compounds for
plastic may leave scratches on the wind-
shield. Test the product on a small hidden
part of the windshield to make sure that it
does not leave any marks. If the wind-
shield is scratched, use a quality plastic
polishing compound after washing.
After normal use
Remove dirt with warm water, a mild detergent,
and a soft, clean sponge, and then rinse thor-
oughly with clean water. Use a toothbrush or
bottlebrush for hard-to-reach areas. Stubborn
dirt and insects will come off more easily if the
area is covered with a wet cloth for a few min-
utes before cleaning.
After riding in the rain, near the sea or on salt-
sprayed roads
Since sea salt or salt sprayed on roads during
winter are extremely corrosive in combination
with water, carry out the following steps after
each ride in the rain, near the sea or on salt-
sprayed roads.
TIP
Salt sprayed on roads in the winter may remain
well into spring.
1. Clean the motorcycle with cold water and a
mild detergent, after the engine has cooled
down.
NOTICE: Do not use warm water since it
increases the corrosive action of the salt.

ENGINE SPECIFICATIONS
2-2
EAS2GBB062
ENGINE SPECIFICATIONS
Engine
Engine type Liquid cooled 4-stroke, DOHC
Displacement 250 cm
3
Number of cylinders Single cylinder
Bore  stroke 77.0  53.6 mm (3.03  2.11 in)
Compression ratio 13.5:1
Starting system Electric starter and kickstarter
Fuel
Recommended fuel Premium unleaded gasoline only
Fuel tank capacity 7.5 L (2.0 US gal, 1.7 Imp.gal)
Fuel reserve amount 2.1 L (0.55 US gal, 0.46 lmp.gal)
Engine oil
Lubrication system Wet sump
Recommended brand YAMALUBE
Type SAE 10W-40, SAE 10W-50, SAE 15W-40,
SAE 20W-40 or SAE 20W-50
Recommended engine oil grade API service SG type or higher, JASO standard
MA
Engine oil quantity
Quantity (disassembled) 1.10 L (1.16 US qt, 0.97 Imp.qt)
Oil change 0.83 L (0.88 US qt, 0.73 Imp.qt)
With oil filter removal 0.85 L (0.90 US qt, 0.75 Imp.qt)
Oil filter
Oil filter type Paper
Bypass valve opening pressure 40.0–80.0 kPa (0.40–0.80 kgf/cm
2,
5.8–11.6 psi)
Oil pump
Oil pump type Trochoid
Inner-rotor-to-outer-rotor-tip clearance 0.000–0.150 mm (0.0000–0.0059 in)
Limit 0.23 mm (0.0091 in)
Outer-rotor-to-oil-pump-housing clearance 0.13–0.18 mm (0.0051–0.0071 in)
Limit 0.25 mm (0.0098 in)
Oil-pump-housing-to-inner-and-outer-rotor
clearance 0.06–0.11 mm (0.0024–0.0043 in)
Limit 0.18 mm (0.0071 in)
Cooling system
Radiator (including all routes) 1.00 L (1.06 US qt, 0.88 Imp.qt)
Radiator capacity 0.56 L (0.59 US qt, 0.49 Imp.qt)
Radiator cap valve opening pressure 107.9–137.3 kPa (1.08–1.37 kg/cm
2,
15.6–19.9 psi)
Radiator core
Width 112.6 mm (4.43 in)
Height 235.0 mm (9.25 in)
Depth 28.0 mm (1.10 in)
Water pump
Water pump type Single suction centrifugal pump
Spark plug(s)
Manufacturer/model NGK/LMAR8G
Spark plug gap 0.7–0.8 mm (0.028–0.031 in)

ENGINE SPECIFICATIONS
2-6
Throttle body
Type/quantity 30RA-A95R/1
ID mark 2GB1 00
Fuel line pressure (at idle) 300.0–390.0 kPa (3.00–3.90 kgf/cm
2,
43.5–56.6 psi)
Throttle position sensor
Resistance 6.30 k
Output voltage (at idle) 0.48–0.52 V
Fuel injection sensor
Crankshaft position sensor resistance 228–342 
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 5400.0–6600.0  at 0 °C (5400.0–6600.0 
at 32 °F)
289–391  at 80 °C (289–391  at 176 °F)
Coolant temperature sensor resistance 2512–2777  at 20 °C (2512–2777  at 68 °F)
210–220  at 100 °C (210–220  at 212 °F)
Idling condition
Engine idling speed 1900–2100 r/min
CO% 3.0–4.0 % (USA) (CAN)
Intake vacuum 27.3 kPa (205 mmHg, 8.1 inHg) (USA) (CAN)
Water temperature 70–90 °C (158–194 °F)
Oil temperature 70–80 °C (158–176 °F)
Throttle grip free play 3.0–6.0 mm (0.12–0.24 in)

CABLE ROUTING DIAGRAM
2-34
1. Clamp
2. Cylinder head breather hose
3. Throttle position sensor lead
4. Joint coupler
5. Intake air temperature sensor lead
6. Intake air pressure sensor lead
7. Wire harness
8. Injector lead
9. Throttle body
10. Injector coupler
11. Starter motor lead
12. Plastic band
13. Fuel sender coupler
14. High tension cord
15. Spark plug cap
16. Cylinder head cover
17. Fuel hose
18. Fuel sender
19. Sub-wire harness
20. Crankcase breather hose
21. Radiator breather hose
22. Radiator hose
23. Down tube
24. Starter motor
25. Neutral switch lead
26. AC magneto lead
27. Clutch cable
28. Radiator
29. Air filter case breather hose
30. Breather hose clamp
31. Grommet (high tension cord)
32. ECU
33. Air filter case
34. Sub-wire harness coupler
35. Engine bracket
A. Fix the wire harness, clutch switch lead and start
switch lead by the clamp, and insert the projec-
tion of the clamp into the hole in the sheet metal
of the radiator.
B. Route each lead so that the leads are not pinched
between the tank rail and air filter joint.
C. Insert the projection of the wire harness into the
hole in the frame.
D. Route the cylinder head breather hose without it
crossing the starter motor lead.
E. Pass the cylinder head breather hose between
the throttle cable and rectifier/regulator lead.
F. Connect the sub-wire harness to the wire har-
ness.
G. Pass the high tension cord above the fuel hose.
H. ±10°
I. Install the spark plug cap with this facing the right
of the vehicle.
J. Push the spark plug cap home, where there shall
be no gap between it and the cylinder head cover.
K. Pass the radiator breather hose between the
down tubes.
L. 50±3 mm (2.0±0.12 in)
M. Apply adhesive to the slit and inside of the grom-
met, and then fix the grommet according to the
specified dimensions.
N. Pass the sub-wire harness between the ECU and
the air filter case.
O. Insert the coupler of the sub-wire harness into the
rib of the air filter case.
P. Route the radiator breather hose through be-
tween the radiator hose, down tube and engine
bracket.

CABLE ROUTING DIAGRAM
2-36
1. Cable guide
2. Speed sensor lead
3. Joint coupler
4. Ground lead
5. Throttle position sensor lead
6. Throttle position sensor coupler
7. Radiator breather hose
8. Cylinder head breather hose
9. Crankcase breather hose
10. Radiator hose
11. Fuel hose
12. Engine ground lead
13. Coolant temperature sensor coupler
14. Radiator fan motor lead
15. Intake air pressure sensor coupler
16. Intake air temperature sensor coupler
17. Start switch coupler
18. Radiator fan motor coupler
19. Clutch switch coupler
20. Air filter case
21. Plate
22. Bracket
A. Pass the wire harness under the start switch lead
and clutch switch lead.
B. Insert and fix the joint coupler to the plate. After
fixing it, attach the cover.
C. Pass the throttle position sensor lead to the out-
side of the tension arm (the outside of the vehi-
cle).
D. After connecting the throttle position sensor cou-
pler, attach the cover.
E. Pass the radiator breather hose to the outside of
the tension arm and the throttle position sensor
lead (the outside of the vehicle), and to the inside
of the radiator hose (the side of the vehicle).
F. 45°
G. Install the engine ground lead within a range of
45° from a location where it will not run over the
step difference of the radiator hose joint. Both
sides of the engine ground lead terminal can be
used.
H. Attach the coupler cover to the coolant tempera-
ture sensor coupler.
I. Pass the radiator fan motor lead to the inside of
the tension arm (the side of the vehicle).
J. Install the ground lead terminal between the plate
and the bolt.
K. Fix the ground lead terminal to the detent in the
plate. For the ground lead terminal, either side
will do.
L. Detent

3
PERIODIC CHECKS AND ADJUSTMENTS
PERIODIC MAINTENANCE............................................................................. 3-1
INTRODUCTION ........................................................................................ 3-1
PERIODIC MAINTENANCE CHART FOR THE EMISSION CONTROL
SYSTEM .................................................................................................... 3-1
GENERAL MAINTENANCE AND LUBRICATION CHART ........................ 3-2
MAINTENANCE INTERVALS FOR COMPETITION USE ......................... 3-4
PRE-OPERATION INSPECTION AND MAINTENANCE................................. 3-9
GENERAL INSPECTION AND MAINTENANCE........................................ 3-9
ENGINE.......................................................................................................... 3-10
CHECKING THE COOLANT LEVEL ........................................................ 3-10
CHECKING THE COOLING SYSTEM ..................................................... 3-10
CHANGING THE COOLANT.................................................................... 3-10
CHECKING THE RADIATOR CAP .......................................................... 3-11
CHECKING THE RADIATOR CAP VALVE OPENING PRESSURE ....... 3-11
CHECKING THE COOLANT CIRCULATORY SYSTEM FOR LEAKS .... 3-12
ADJUSTING THE CLUTCH LEVER FREE PLAY .................................... 3-12
ADJUSTING THE THROTTLE GRIP FREE PLAY .................................. 3-13
LUBRICATING THE THROTTLE CABLE ................................................ 3-14
CLEANING THE AIR FILTER ELEMENT................................................. 3-14
CHECKING THE THROTTLE BODY JOINT ............................................ 3-15
CHECKING THE BREATHER HOSES .................................................... 3-15
CHECKING THE EXHAUST SYSTEM..................................................... 3-15
CHECKING THE FUEL LINE ................................................................... 3-16
CHECKING THE ENGINE OIL LEVEL..................................................... 3-16
CHANGING THE ENGINE OIL ................................................................ 3-17
ADJUSTING THE ENGINE IDLING SPEED ............................................ 3-18
ADJUSTING THE VALVE CLEARANCE ................................................. 3-19
CLEANING THE SPARK ARRESTER ..................................................... 3-24
CHASSIS........................................................................................................ 3-25
BLEEDING THE BRAKE SYSTEM .......................................................... 3-25
CHECKING THE BRAKE HOSE .............................................................. 3-26
ADJUSTING THE FRONT BRAKE .......................................................... 3-26
ADJUSTING THE REAR BRAKE ............................................................. 3-27
CHECKING THE FRONT BRAKE PADS ................................................. 3-27
CHECKING THE REAR BRAKE PADS ................................................... 3-29
CHECKING THE REAR BRAKE PAD INSULATOR ................................ 3-30
CHECKING THE BRAKE FLUID LEVEL.................................................. 3-30
ADJUSTING THE DRIVE CHAIN SLACK ................................................ 3-31
CHECKING THE FRONT FORK LEGS ................................................... 3-32
CHECKING THE FRONT FORK PROTECTOR GUIDE .......................... 3-32
CLEANING THE FRONT FORK OIL SEAL AND DUST SEAL ................ 3-32
AIR BLEEDING FROM FRONT FORK .................................................... 3-32
ADJUSTING THE FRONT FORK LEGS .................................................. 3-33
CHECKING THE SWINGARM OPERATION ........................................... 3-34
CHECKING THE REAR SUSPENSION ................................................... 3-34

PRE-OPERATION INSPECTION AND MAINTENANCE
3-9
EAS2GBB079
PRE-OPERATION INSPECTION AND MAINTENANCE
Before riding for break-in operation, practice or a race, make sure the machine is in good operating
condition.
Before using this machine, check the following points.
EAS2GBB080GENERAL INSPECTION AND MAINTENANCE
TIP
Perform usual maintenance enough so that, in the race course, a confirmation of that and simple set-
ting adjustments may only be left, in order to get enough time to use effectively.ITEM inspect Page
CoolantCheck that coolant is filled up to the radiator cap.
Check the cooling system for leakage.3-10 – 12
FuelCheck that a fresh gasoline is filled in the fuel tank.
Check the fuel line for leakage.1-30
Engine oilCheck that the oil level is correct. Check the crank-
case and oil line for leakage.3-16 – 18
Gear shifter and clutchCheck that gears can be shifted correctly in order and
that the clutch operates smoothly.3-12 – 13
Throttle grip/HousingCheck that the throttle grip operation and free play
are correctly adjusted. Lubricate the throttle grip and
housing, if necessary.3-13 – 14
BrakesCheck the play of front brake and effect of front and
rear brake.3-25 – 31
Drive chainCheck drive chain slack and alignment. Check that
the drive chain is lubricated properly.3-31
5-69 – 71
WheelsCheck for excessive wear and tire pressure. Check
for loose spokes and have no excessive play.3-36 – 37
SteeringCheck that the handlebar can be turned smoothly and
have no excessive play.3-37 – 38
Front forks and rear
shock absorberCheck that they operate smoothly and there is no oil
leakage.3-32 – 36
Cables (wires)Check that the clutch and throttle cables move
smoothly. Check that they are not caught when the
handlebars are turned or when the front forks travel
up and down.—
Exhaust pipeCheck that the exhaust pipe is tightly mounted and
has no cracks.3-15 – 16
Rear wheel sprocketCheck that the rear wheel sprocket tightening bolt is
not loose.5-10 – 11
LubricationCheck for smooth operation. Lubricate if necessary. 3-14
3-38 – 39
Bolts and nutsCheck the chassis and engine for loose bolts and
nuts.1-34 – 35
Lead connectorsCheck that the AC magneto, ECU and ignition coil are
connected tightly.1-9 – 12
SettingsIs the machine set suitably for the condition of the rac-
ing course and weather or by taking into account the
results of test runs before racing? Are inspection and
maintenance completely done?4-1 – 8

ENGINE
3-18
d. Install the oil strainer.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
6. Install:
•Gasket
• Drain bolt
7. Pour the specified amount of engine oil into
the oil filler cap hole.
8. Install:
• Oil filler cap
9. Check:
• Oil level
Refer to “CHECKING THE ENGINE OIL
LEVEL” on page 3-16.
10.Check:
• Engine oil pressure
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Slightly loosen the oil pressure check bolt
“1”.
EWA
WARNING
When the engine is started with the check
bolt removed, oil will spout; therefore, al-
ways loosen it before the checkup.b. Start the engine and keep it idling until oil
starts to seep from the oil pressure check
bolt.
EWA
WARNING
Always keep the engine idling speed during
the checkup without increasing the engine
speed.
ECA
NOTICE
If no engine oil seeps out after one minute,
immediately turn the engine off so it will not
seize.
c. If no engine oil seeps out, check the engine
oil for leaks, and the engine oil passage and
the oil pump for damage.
d. Check the oil pressure again.
e. Tighten the oil pressure check bolt.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
EAS2GBB098ADJUSTING THE ENGINE IDLING SPEED
TIP
• Because the air pressure is lower at high alti-
tudes, the air-fuel mixture will become richer.
If the idling speed is low, turn the starter knob/
idle screw a few clicks counterclockwise to in-
crease the speed before the adjustment.
• Before adjusting the engine idling speed,
make sure that the air filter element is not
clogged, the engine compression is proper,
and the throttle grip free play is proper.
• Adjust the engine idling speed with the starter
knob/idle screw pushed in completely. Oil strainer bolt
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Drain bolt
20 Nm (2.0 m·kgf, 14 ft·lbf)
Engine oil quantity
Oil change
0.83 L (0.88 US qt, 0.73 Imp.qt)
With oil filter removal
0.85 L (0.90 US qt, 0.75 Imp.qt)
Quantity (disassembled)
1.10 L (1.16 US qt, 0.97 Imp.qt)
T R..
New
T R..
Oil pressure check bolt
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
1
T R..