2017 YAMAHA WR 250F Owners Manual

ENGINE
3-21
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.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 6-12. Valve lapper
90890-04101
Valve lapping tool
YM-A8998
1
32
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
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.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲

ENGINE
3-23
INTAKE
Example:
Valve clearance (cold) 0.12–0.19 mm
(0.0047–0.0075 in)
Installed is 175
Measured clearance 0.27 mm (0.0106 in)
Replace 175 pad with 185 pad
Pad No.175 = 1.75 mm (0.0689 in)
Pad No.185 = 1.85 mm (0.0728 in)
0.12 0.19
0.250.29 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.30
0.34 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.35
0.39 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.40
0.44 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.45
0.49 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.50
0.54 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.55
0.59 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.60
0.64 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.65
0.69 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.70
0.74 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.75
0.79 180 185 190 195 200 205 210 215 220 225 230 235 240
0.80
0.84 185 190 195 200 205 210 215 220 225 230 235 240
0.85
0.89 190 195 200 205 210 215 220 225 230 235 240
0.90
0.94 195 200 205 210 215 220 225 230 235 240
0.95
0.99 200 205 210 215 220 225 230 235 240
1.00
1.04 205 210 215 220 225 230 235 240
1.05
1.09 210 215 220 225 230 235 240
1.10
1.14 215 220 225 230 235 240
1.15
1.19 220 225 230 235 240
1.20
1.24 225 230 235 240
1.25
1.29 230 235 240
1.30
1.34 235 240
1.35
1.39 240
120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.02 0.06
120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 0.00
0.01120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225
0.07 0.11 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235
0.20 0.24 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
A. Measured clearance
B. Installed pad number
C. Standard clearance

ENGINE
3-24
EXHAUST
Example:
Valve clearance (cold) 0.17–0.24 mm
(0.0067–0.0094 in)
Installed is 175
Measured clearance 0.32 mm (0.0126 in)
Replace 175 pad with 185 pad
Pad No.175 = 1.75 mm (0.0689 in)
Pad No.185 = 1.85 mm (0.0728 in)
EAS2GBB100CLEANING THE SPARK ARRESTER
Refer to “CLEANING THE SPARK ARREST-
ER” on page 6-7.
0.17 0.24
0.25
0.29 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.30
0.34 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.35
0.39 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.40
0.44 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.45
0.49 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.50
0.54 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.55
0.59 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.60
0.64 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.65
0.69 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.70
0.74 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.75
0.79 175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.80
0.84 180 185 190 195 200 205 210 215 220 225 230 235 240
0.85
0.89 185 190 195 200 205 210 215 220 225 230 235 240
0.90
0.94 190 195 200 205 210 215 220 225 230 235 240
0.95
0.99 195 200 205 210 215 220 225 230 235 240
1.00
1.04 200 205 210 215 220 225 230 235 240
1.05
1.09 205 210 215 220 225 230 235 240
1.10
1.14 210 215 220 225 230 235 240
1.15
1.19 215 220 225 230 235 240
1.20
1.24 220 225 230 235 240
1.25
1.29 225 230 235 240
1.30
1.34 230 235240
1.35
1.39 235 240
1.40
1.44 240 0.00
0.01 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220
0.02
0.06 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225
0.07
0.11 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230
0.12
0.16 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235
120 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240
A. Measured clearance
B. Installed pad number
C. Standard clearance

CHASSIS
3-25
EAS2GBB101
CHASSIS
EAS2GBB102BLEEDING THE BRAKE SYSTEMEWA
WARNING
Bleed the brake system whenever:
• The system is disassembled.
• A brake hose is loosened, disconnected,
or replaced.
• The brake fluid level is very low.
• Brake operation is faulty.
1. Remove:
• Brake master cylinder cap
• Reservoir diaphragm
• Reservoir float (front brake)
• Protector (rear brake)
TIP
• Be careful not to spill any brake fluid or allow
the reservoir to overflow.
• Make sure that there is enough brake fluid be-
fore applying the brake. Ignoring this precau-
tion could allow air to enter the brake system,
considerably lengthening the bleeding proce-
dure.
• If bleeding is difficult, it may be necessary to
let the brake fluid settle for a few hours. Re-
peat the bleeding procedure when the tiny
bubbles in the hose have disappeared.
2. Bleed the brake system.
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Fill the reservoir to the proper level with the
recommended brake fluid.
b. Install the reservoir diaphragm.
c. Connect the plastic hose “1” to the bleed
screw “2” securely, and place a container
under the end of the plastic hose.d. Slowly apply the brake several times.
e. Fully pull the brake lever or fully press down
the brake pedal and hold it in position.
f. Loosen the bleed screw.
TIP
Loosening the bleed screw will release the
pressure in the brake caliper and cause the
brake lever to contact the throttle grip or the
brake pedal to fully extend.
g. Tighten the bleed screw and then release
the brake lever or brake pedal.
h. Repeat steps (d) to (g) until all of the air bub-
bles have disappeared from the brake fluid
in the plastic hose.
TIP
During the procedure, keep adding brake fluid
to the reservoir.
ECA
NOTICE
• Wipe off any brake fluid on the brake
discs, tires, wheels, etc.
• Brake fluid may erode painted surfaces or
plastic parts. Always clean up spilled fluid
immediately.
i. Tighten the bleed screw.
j. Pour brake fluid to the reservoir up to the
specified level.
Refer to “CHECKING THE BRAKE FLUID
LEVEL” on page 3-30.
EWA
WARNING
After bleeding the hydraulic brake system,
check the brake operation.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
1 2
A
A. Front
B. Rear
Bleed screw
6 Nm (0.6 m·kgf, 4.3 ft·lbf)
2
1B
T R..

CHASSIS
3-26
EAS2GBB103CHECKING THE BRAKE HOSE
1. Check:
• Brake hose “1”
Cracks/damage/wear  Replace.
2. Check:
• Brake hose clamp
Loose connection  Tighten the clamp bolt.
3. Stand the vehicle upright and apply the front
brake and the rear brake several times.
4. Check:
• Brake hoses
Brake fluid leaks  Replace the damaged
brake hose.
Refer to “FRONT BRAKE” on page 5-13.
Refer to “REAR BRAKE” on page 5-23.
EAS2GBB104ADJUSTING THE FRONT BRAKE
1. Check:
• Brake lever position “a”2. Remove:
• Brake lever cover
3. Adjust:
• Brake lever position
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Loosen the locknut “1”.
b. Turn the adjusting bolt “2” in direction “a” or
“b” until the specified brake lever position is
obtained.
c. Tighten the locknut.
EWA
WARNING
A soft or spongy feeling in the brake lever
can indicate the presence of air in the brake
system. Before the vehicle is operated, the
air must be removed by bleeding the brake
system. Air in the brake system will consid-
erably reduce braking performance.
ECA
NOTICE
After adjusting the brake lever position,
make sure there is no brake drag.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
4. Install:
• Brake lever cover
A. Front
B. Rear
Brake lever position
95 mm (3.74 in)
Extent of adjustment
76–97 mm (2.99–3.82 in)
1
1
Direction “a”
Brake lever position is increased.
Direction “b”
Brake lever position is decreased.
Locknut
5 Nm (0.5 m·kgf, 3.6 ft·lbf)
a
b
T R..

CHASSIS
3-27
EAS2GBB105ADJUSTING THE REAR BRAKE
1. Check:
• Brake pedal position “a”
(distance from the top of the rider footrest to
the top of the brake pedal)
Out of specification  Regulate.
2. Adjust:
• Brake pedal position
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Loosen the locknut “1”.
b. Turn the adjusting bolt “2” in direction “a” or
“b” until the specified brake pedal position is
obtained.
c. Tighten the locknut.
EWA
WARNING
A soft or spongy feeling in the brake pedal
can indicate the presence of air in the brake
system. Before running, bleed the brake
system. Air in the brake system will cause
braking performance to be reduced.
ECA
NOTICE
After adjusting the brake pedal position,
make sure that there is no brake drag.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
EAS2GBB106CHECKING THE FRONT BRAKE PADS
1. Measure:
• Brake pad thickness “a”
Out of specification  Replace as a set.
TIP
The pads worn up to the indicator “b” grooves
mean that the brake pad thickness limit is
reached.
2. Replace:
• Brake pads
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Remove the pad pin plug “1”.
b. Loosen the pad pin “2”. Brake pedal position
5.0 mm (0.20 in)
Direction “a”
Brake pedal is raised.
Direction “b”
Brake pedal is lowered.
Locknut
6 Nm (0.6 m·kgf, 4.3 ft·lbf)
1 2
a
b
T R..
Brake pad lining thickness
4.4 mm (0.17 in)
Limit
1.0 mm (0.04 in)
a
b
a
1

CHASSIS
3-28
c. Remove the brake caliper “3” from the front
fork.
d. Remove the pad pin and brake pads “4”.
e. Connect the plastic hose “5” to the bleed
screw “6” and place a container under the
end of the plastic hose.
f. Loosen the bleed screw and push the brake
caliper piston in.
EWA
WARNING
Do not reuse the drained brake fluid.
g. Tighten the bleed screw.
h. Install the brake pads “7” and the pad pin.
TIP
• Install the brake pads with their projections “a”
into the brake caliper recesses “b”.
• Temporarily tighten the pad pin at this point.i. Install the brake caliper “8” and tighten the
pad pin “9”.
j. Install the pad pin plug “10”.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
3. Check:
• Brake fluid level
Refer to “CHECKING THE BRAKE FLUID
LEVEL” on page 3-30.
4. Check:
• Brake lever operation
A softy or spongy feeling  Bleed the brake
system.
Refer to “BLEEDING THE BRAKE SYS-
TEM” on page 3-25. Bleed screw
6 Nm (0.6 m·kgf, 4.3 ft·lbf)
3
2
4
6
5
T R..
Bolt (brake caliper)
23 Nm (2.3 m·kgf, 17 ft·lbf)
Pad pin
17 Nm (1.7 m·kgf, 12 ft·lbf)
Pad pin plug
2.5 Nm (0.25 m·kgf, 1.8 ft·lbf)
7
a b
T R..
8
9
T R..
10