2015 YAMAHA WR 250F engine

ENGINE
3-18
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
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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.
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.
b. If no engine oil seeps out, check the engine
oil for leaks, and the engine oil passage and
the oil pump for damage.
c. Check the oil pressure again.
d. Tighten the oil pressure check bolt.
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EAS2GB2100
ADJUSTING 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.
1. Start the engine, and warm this up until the
oil has reached the specified temperature.
2. Attach the pocket tester with temperature
probe “1” to the oil drain bolt.
3. Install:
• Digital tachometer
TIP
Get the high tension cord “1” of the ignition coil
pinched in the detector “a” of the digital tachom-
eter.
Oil pressure check bolt
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
1
T R..
Oil temperature
70.0–80.0 °C (158.00–176.00 °F)
Digital tachometer
90890-06760
Digital tachometer
YU-39951-B
1
1 1
a a

ENGINE
3-19
4. Measure:
• Engine idling speed
Out of specification  Regulate.
5. Adjust:
• Engine idling speed
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a. Turn the starter knob/idle screw “1” in the di-
rection of “a” or “b” to make an adjustment.
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EAS2GB2101ADJUSTING THE VALVE CLEARANCE
TIP
• This section is intended for those who have
basic knowledge and skill concerning the ser-
vicing of Yamaha motorcycles (e.g., Yamaha
dealers, service engineers, etc.). Those who
have little knowledge and skill concerning ser-
vicing are requested not to undertake inspec-
tion, adjustment, disassembly, or reassembly
only by reference to this manual. It may lead
to servicing trouble and mechanical damage.
• Make sure that the valve clearance is
checked or adjusted while the engine is cold
(at room temperature).
• While the valve clearance is checked or ad-
justed, make sure that the piston is positioned
in the top dead center (TDC).1. Remove:
• Seat
• Side cover (left/right)
• Air scoop (left/right)
Refer to “GENERAL CHASSIS” on page 5-
1.
• Fuel tank
Refer to “FUEL TANK” on page 8-1.
•ECU
2. Remove:
• Spark plug
• Cylinder head cover
Refer to “CAMSHAFT” on page 6-11.
3. Remove:
• Timing mark accessing screw “1”
• Crankshaft end accessing screw “2”
• O-ring
4. Check:
• Valve clearance
Out of specification  Regulate.
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a. Turn the crankshaft counterclockwise with a
wrench.
b. Align the top dead center (TDC) mark “a” on
the rotor with the alignment mark “b” on the
crankcase cover. Engine idling speed
1900–2100 r/min
Direction “a” Engine idling speed  De-
creases.
Direction “b” Engine idling speed  In-
creases.
1 b
a
Valve clearance (cold)
Intake
0.12–0.19 mm (0.0047–0.0075 in)
Exhaust
0.17–0.24 mm (0.0067–0.0094 in)
12
ab

ENGINE
3-20
TIP
Check that the alignment mark “c” on the cam-
shaft sprocket and the alignment mark “d” on
the intake camshaft sprocket are aligned with
the edge of the cylinder head.
c. Measure the valve clearance “e” using a
thickness gauge “1”.
TIP
Record the measured reading if the clearance
is incorrect.
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5. Adjust:
• Valve clearance
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a. Remove the camshaft (intake and exhaust).
Refer to “CAMSHAFT” on page 6-11.
b. Remove the valve lifter “2” and the adjusting
pad “3” with a valve lapper “1”.
TIP
• Place a cloth in the timing chain space to pre-
vent adjusting pads from falling into the crank-
case.
• Identity each valve lifter and adjusting pad po-
sition very carefully so that they can be rein-
stalled in their original place.
c. Check the number on the originally installed
adjusting pad.
TIP
• The adjusting pad number “a” is indicated on
the top of the adjusting pad.
• For the number on the originally installed ad-
justing pad, convert the last digit of adjusting
pad number as per the below table.
dc
ee
1
Valve lapper
90890-04101
Valve lapping tool
YM-A8998
1
32

ENGINE
3-21
d. Select an adjusting pad with a proper valve
clearance from the adjusting pad selection
table.
TIP
• There are 25 types of adjusting pads, ranging
from 1.20 mm (0.0472 in) to 2.40 mm (0.0945
in), in increments of 0.05 mm (0.0020 in).
• The field where the number on the originally
installed adjusting pad and the measured
valve clearance intersect shows the adjusting
pad number to replace.
Example:
Pad number = 148
Rounded value = 150
e. Install the new adjusting pads “4” and the
valve lifters “5”.
ECA
NOTICE
Do not twist adjusting pads and valve lifters
forcibly during installation.
TIP
• Apply the engine oil on the valve lifters.
• Apply molybdenum disulfide oil to the valve
stem ends.
• Check that the valve lifters turn smoothly
when rotated with your finger.
• Make sure that valve lifters and adjusting
pads are installed in place.
• Make sure that adjusting pads are installed
with their numbers facing upward.f. Install the camshafts (exhaust and intake).
Refer to “CAMSHAFT” on page 6-11.
g. Measure the valve clearance again.
h. If the valve clearance is out of specification,
repeat adjusting the valve clearance until it
is within specification.
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Last digit of pad
numberRounded valve
0, 1 or 2 0
4, 5 or 6 5
8 or 9 10
4 5

ENGINE
3-22
INTAKE
EXHAUST
120 125 130 135 140 145 150 155 160 165 170175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.02
0.06 0.00 0.01
120 125 130 135 140 145 150 155160165 170 175 180 185 190 195 200 205 210 215 220 225 230 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225
0.07
0.11120 125 130 135 140 145 150 155 160 165170 175 180 185 190 195 200 205 210 215 220 225 230 235
0.12
0.19
0.20
0.24125130135140145150155160165170175180 185 190 195 200 205 210 215 220 225 230 235240
0.250.29130135140145150155160165170175180185 190 195 200 205 210 215 220 225 230 235240
0.30 0.34 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
0.35 0.39 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
0.40 0.44 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
0.45 0.49 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
0.50 0.54 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
0.55 0.59 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
0.600.64 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
0.65 0.69 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
0.70 0.74 175 180 185 190 195 200 205 210 215 220 225 230 235240
0.75 0.79 180 185 190 195 200 205 210 215 220 225 230 235240
0.80 0.84 185 190 195 200 205 210 215 220 225 230 235240
0.85 0.89 190 195 200 205 210 215 220 225 230 235240
0.90 0.94 195 200 205 210 215 220 225 230 235240
0.95 0.99 200 205 210 215 220 225 230 235240
1.001.04 205 210 215 220 225 230 235240
1.05 1.09 210 215 220 225 230 235240
1.10 1.14 215 220 225 230 235240
1.15 1.19 220 225 230 235240
1.20 1.24 225 230 235240
1.25 1.29 230 235240
1.30 1.34 235240
1.35 1.39 240
0.19
0.12
120 125 130 135 140 145 150 155 160 165 170175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.00
0.01 120 125 130 135 140 145150155 160 165 170 175 180 185 190 195 200 205 210 215 220
0.02
0.06120 125 130 135 140 145 150 155160 165 170 175 180 185 190 195 200 205 210 215 220 225
0.07
0.11120 125 130 135 140 145 150 155 160165 170 175 180 185 190 195 200 205 210 215 220 225 230
0.12 0.16120125130135140145150155160165170 175 180 185 190 195 200 205 210 215 220 225230235
0.17
0.24
0.25 0.29 125 130 135 140 145 150 155 160 165 170 175180 185 190 195 200 205 210 215 220 225230235240
0.30 0.34130135140145150155160165170175180185 190 195 200 205 210 215 220 225230235240
0.35 0.39 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.40 0.44 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.45 0.49 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.50 0.54 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.55 0.59 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.60 0.64 160 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.65 0.69 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.70 0.74 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.75 0.79 175 180 185 190 195 200 205 210 215 220 225230235240
0.80 0.84 180 185 190 195 200 205 210 215 220 225230235240
0.85 0.89 185 190 195 200 205 210 215 220 225230235240
0.90 0.94 190 195 200 205 210 215 220 225230235240
0.95 0.99 195 200 205 210 215 220 225230235240
1.00 1.04 200 205 210 215 220 225230235240
1.05 1.09 205 210 215 220 225230235240
1.10 1.14 210 215 220 225230235240
1.15 1.19 215 220 225230235240
1.20 1.24 220 225230235240
1.25 1.29 225230235240
1.30 1.34 230235240
1.35 1.39 235240
1.40 1.44 240
0.24
0.17

ENGINE
3-23
EAS2GB2102CLEANING THE SPARK ARRESTER
Refer to “CLEANING THE SPARK ARREST-
ER” on page 6-7.

CHASSIS
3-30
EWA
WARNING
• Use only the designated brake fluid. Other
brake fluids may cause the rubber seals to
deteriorate, causing leakage and poor
brake performance.
• Refill with the same type of brake fluid that
is already in the system. Mixing brake flu-
ids may result in a harmful chemical reac-
tion, leading to poor brake performance.
• When refilling, be careful that water does
not enter the brake fluid reservoir. Water
will significantly lower the boiling point of
the brake fluid and could cause vapor
lock.
ECA
NOTICE
Brake fluid may damage painted surfaces
and plastic parts. Therefore, always clean
up any spilt brake fluid immediately.
EAS2GB2112ADJUSTING THE DRIVE CHAIN SLACKECA
NOTICE
A drive chain that is too tight will overload
the engine and other vital parts, and one
that is too loose can skip and damage the
swingarm or cause an accident. Therefore,
keep the drive chain slack within the speci-
fied limits.
1. Use a suitable stand to raise the rear wheel
off the ground.
EWA
WARNING
Securely support the vehicle so that there is
no danger of it falling over.
2. Shift the transmission into the neutral posi-
tion.
3. Pull the drive chain up above the drive chain
guide installation bolt with a force of about
50 N (5.0 kgf, 36 lbf).
4. Check:
• Drive chain slack “a”
Out of specification  Regulate.
TIP
Measure drive chain slack between the drive
chain guide and the bottom of the chain as
shown.5. Adjust:
• Drive chain slack
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a. Loosen the wheel axle nut “1”.
b. Loosen both locknuts “2”.
c. Turn the adjusting bolt “3” in direction “a” or
“b” until the specified drive chain slack is ob-
tained.
TIP
• To maintain the proper wheel alignment, ad-
just both sides evenly.
• Push the rear wheel forward to make sure that
there is no clearance between the swingarm
end plates and the ends of the swingarm.
d. Tighten the locknut.
e. Tighten the wheel axle nut.
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Drive chain slack
50–60 mm (1.97–2.36 in)
Direction “a”
The drive chain slack decreases.
Direction “b”
The drive chain slack increases.
Locknut
21 Nm (2.1 m·kgf, 15 ft·lbf)
Wheel axle nut
125 Nm (12.5 m·kgf, 90 ft·lbf)
a
1
32
a
b
T R..
T R..

CHASSIS
3-37
c. Turn the front fork to the right and left a few
times, and make sure that the steering ro-
tates smoothly. If it does not turn smoothly,
remove the lower bracket and check the up-
per and lower bearings.
Refer to “STEERING HEAD” on page 5-53.
d. Loosen the ring nut fully turn and then tight-
en it to specification with a steering nut
wrench.
EWA
WARNING
Do not overtighten the lower ring nut.
e. Check the steering head for looseness or
binding by turning the front fork all the way in
both directions. If any binding is felt, remove
the lower bracket and check the upper and
lower bearings.
Refer to “STEERING HEAD” on page 5-53.
f. Install the washer “1”.
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5. Install:
• Upper bracket
Refer to “STEERING HEAD” on page 5-53.
• Handlebar
Refer to “HANDLEBAR” on page 5-33.
EAS2GB2126
CHECKING AND LUBRICATING THE CA-
BLES
The following procedure applies to all of the in-
ner and outer cables.
EWA
WARNING
Damaged outer cable may cause the cable
to corrode and interfere with its movement.
Replace damaged outer cable and inner ca-
bles as soon as possible.
1. Check:
• Outer cable
Damage  Replace.
2. Check:
• Cable operation
Rough movement  Lubricate.
TIP
Hold the cable end upright and pour a few
drops of lubricant into the cable sheath or use
a suitable lubricating device.
EAS2GB2127LUBRICATING THE LEVERS
1. Lubricate the pivoting points and metal-to-
metal moving parts of the following parts.
•Brake lever
• Clutch lever
EAS2GB2128LUBRICATING THE PEDAL
1. Lubricate the pivoting point and metal-to-
metal moving parts of the pedal. Steering nut wrench
90890-01403
Exhaust flange nut wrench
YU-A9472
Ring nut (initial tightening torque)
38 Nm (3.8 m·kgf, 27 ft·lbf)
Ring nut (final tightening torque)
7 Nm (0.7 m·kgf, 5.1 ft·lbf)
T R..
T R..
1
Recommended lubricant
Engine oil or a suitable cable lu-
bricant
Recommended lubricant
Silicone grease
Recommended lubricant
Lithium-soap-based grease
Recommended lubricant
Lithium-soap-based grease