2015 YAMAHA WR 250F oil pressure

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

IMPORTANT INFORMATION
1-9
EAS20180
IMPORTANT INFORMATION
EAS2GB2022PREPARATION FOR REMOVAL AND DIS-
ASSEMBLY
1. Before the jobs, completely remove mud,
dust, and the like in order to prevent the en-
try of them into the inside during the jobs.
• Before cleaning with high-pressure water of
washers, cover the following parts.
Air duct
Silencer exhaust port
Drain hole on the cylinder head (right side)
Hole under the water pump housing
2. Use proper special tools and equipment.
See “SPECIAL TOOLS”.
3. During disassembly, check and measure the
required parts, and make a record of them
so that you may refer to the record when in-
stalling them. Moreover, arrange gears, cyl-
inders, pistons, and other parts for each
section so as not to confuse or lose them.4. During disassembly, clean each of the parts,
and store them in trays for each section.
5. Flammable. Keep servicing areas away
from any source of fire.
6. During servicing, take special care not to re-
ceive an injury or a burn on the engine, the
exhaust pipe, the silencer, or the like.
7. If coolant is left adhered to the chassis, paint
and plating will be damaged. Therefore,
rinse it out with water in good time.
EWA
WARNING
Coolant is potentially harmful and should
be handled with special care.
• If it enters your eyes, wash it away with wa-
ter enough and then get medical attention
• If it splashes on your skin or clothes,
quickly wash it away with water and then
with soapy water.
• If it is swallowed, immediately induce vom-
iting and get medical attention.
EAS2GB2023REPLACEMENT PARTS
Make sure that the parts and grease or oil to be
used for repair of the vehicle, including periodic
replacement parts, are new YAMAHA genuine
parts and recommended parts.
Do not use any used parts, because these may
not be genuine though they have similar ap-
pearances or because the quality may be
changed by aging.

SPECIAL TOOLS
1-16
Radiator cap tester
90890-01325
Mityvac cooling system tester
kit
YU-24460-AThis tool is used to check the
radiator and the radiator cap.
Radiator cap tester adapter
90890-01352
Pressure tester adapter
YU-33984This tool is used to check the
radiator and the radiator cap.
Steering nut wrench
90890-01403
Exhaust flange nut wrench
YU-A9472This tool is used to remove or
tighten the steering nut.
Cap bolt wrench
90890-01500
Cap bolt wrench
YM-01500This tool is used to remove or
tighten the base valve.
Cap bolt ring wrench
90890-01501
Cap bolt ring wrench
YM-01501This tool is used to loosen or
tighten the damper assem-
bly.
Fork seal driver
90890-01502
Fork seal driver (48)
YM-A0948This tool is used to install the
oil seal of the front fork.
Spoke nipple wrench (6–7)
90890-01521
Spoke nipple wrench (6–7)
YM-01521This tool is used to tighten the
spoke. Tool name/Part number How to use Illustration

MAINTENANCE AFTER BREAK-IN
1-35
EAS2GB2057
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.
EAS2GB2058MAJOR 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 1-36.)
• Greasing and oiling
Always grease or oil the specified points.

MOTORCYCLE CARE AND STORAGE
1-38
EAS2GB2060
MOTORCYCLE CARE AND STOR-
AGE
EAS2GB2061CARE
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
EAS2GB2064
ENGINE SPECIFICATIONS
Engine
Engine type Liquid cooled 4-stroke, DOHC
Displacement 250 cm
3
Cylinder arrangement Single cylinder
Bore  stroke 77.0  53.6 mm (3.0  2.1 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 (1.98 US gal, 1.65 Imp.gal)
Fuel reserve amount 1.6 L (0.42 US gal, 0.35 Imp.gal)
Engine oil
Lubrication system Wet sump
Recommended brand YAMALUBE
Type SAE 10W-30, 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)
Without oil filter element replacement 0.83 L (0.88 US qt, 0.73 Imp.qt)
With oil filter element replacement 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 Less than 0.150 mm (0.0059 in)
Limit 0.20 mm (0.0079 in)
Outer-rotor-to-oil-pump-housing clearance 0.13–0.18 mm (0.0051–0.0071 in)
Limit 0.24 mm (0.0094 in)
Oil-pump-housing-to-inner-and-outer-rotor
clearance 0.06–0.11 mm (0.0024–0.0043 in)
Limit 0.17 mm (0.0067 in)
Cooling system
Radiator capacity (including all routes) 1.00 L (1.06 US qt, 0.88 Imp.qt)
Radiator capacity 0.56 L (0.60 US qt, 0.50 Imp.qt)
Radiator cap 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
Manufacturer/model NGK/LMAR8G
Spark plug gap 0.7–0.8 mm (0.028–0.031 in)

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)

CHASSIS SPECIFICATIONS
2-10
Rear suspension
Type Swingarm (link suspension)
Spring/shock absorber type Coil spring/gas-oil damper
Rear shock absorber assembly travel 126.0 mm (4.96 in)
Spring free length 275.0 mm (10.83 in)
Spring installed length 265.0 mm (10.43 in)
Spring rate K1 54.00 N/mm (5.51 kgf/mm, 308.34 lbf/in)
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 preload adjusting positions
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 1-1/4 turn (s) out*
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
Size/manufacturer 520VM2/DAIDO
Number of links 114
Drive chain slack 50–60 mm (1.97–2.36 in)
15-link length limit 239.3 mm (9.42 in)