torque YAMAHA YZ250F 2015 Owner's Manual

CHASSIS
3-33
2. Tighten:
• Spokes
Use a spoke nipple wrench “1” for tighten-
ing.
TIP
• Do not give a half turn (180 °) or more for one
tightening.
• Make sure that tightening after a break-in is
done until the initial looseness in nipples dis-
appears.
• Make sure that tightening is done in stages,
not at a time.
EAS1SM5110CHECKING THE WHEELS
1. Check:
• Wheel (s)
Damage/out-of-round  Replace.
EWA13260
WARNING
Never attempt to make any repairs to the
wheel.
TIP
After replacing a tire or a wheel, always bal-
ance the wheel.
EAS1SM5111CHECKING THE WHEEL BEARINGS
1. Check:
• Wheel bearings
“CHECKING THE FRONT WHEEL” on page
4-4and “CHECKING THE REAR WHEEL”
on page 4-8.
EAS1SM5112
CHECKING AND ADJUSTING THE STEER-
ING HEAD
1. Use a suitable stand to raise the front wheel
off the ground.
EWA13120
WARNING
Securely support the vehicle so that there is
no danger of it falling over.
2. Check:
• Steering head
Grasp the bottom of the front fork legs and
gently rock the front fork.
Blinding/looseness  Adjust the steering
head.
3. Remove:
• Handlebar
Refer to “HANDLEBAR” on page 4-31.
• Upper bracket
Refer to “STEERING HEAD” on page 4-49.
4. Adjust:
• Steering head
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Remove the washer “1”.
b. After loosening the ring nut “2” with a steer-
ing nut wrench “3”, tighten it to the specified
torque.
TIP
• Set the torque wrench at a right angle to the
steering nut wrench.
• Move the steering to the left and right a couple
of times to check that it moves smoothly. Spoke nipple wrench (6–7)
90890-01521
YM-01521
Spokes
2.5 Nm (0.25 m·kgf, 1.8 ft·lbf)
1
T R..
1
3
2

CHASSIS
3-34
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 4-49.
d. Loosen the ring nut fully turn and then tight-
en it to specification with a steering nut
wrench.
EWA13140
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 4-49.
f. Install the washer “1”.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
5. Install:
• Upper bracket
Refer to “STEERING HEAD” on page 4-49.
• Handlebar
Refer to “HANDLEBAR” on page 4-31.
EAS1SM5113
LUBRICATING THE LEVERS
1. Lubricate the pivoting points and metal-to-
metal moving parts of the following parts.
•Brake lever
• Clutch lever
EAS1SM5114LUBRICATING 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
Silicone grease
Recommended lubricant
Lithium-soap-based grease
Recommended lubricant
Lithium-soap-based grease

FRONT FORK
4-48
3. Adjust:
• Front fork top end “a”
4. Tighten:
• Pinch bolt (upper bracket) “1”
• Pinch bolt (lower bracket) “2”
EWA33DD044
WARNING
Tighten the lower bracket to specified
torque. If torqued too much, it may cause
the front fork to malfunction.
5. Install:
• Protector “1”
• Bolt (protector) “2”6. Adjust:
• Rebound damping force
TIP
Turn in the damping adjuster “1” finger-tight
and then turn out to the originally set position.
7. Adjust:
• Compression damping force
TIP
Turn in the damping adjuster “1” finger-tight
and then turn out to the originally set position. Front fork top end (standard) “a”
5 mm (0.20 in)
Upper bracket pinch bolts
21 Nm (2.1 m·kgf, 15 ft·lbf)
Lower bracket pinch bolts
21 Nm (2.1 m·kgf, 15 ft·lbf)
Bolt (protector)
5 Nm (0.5 m·kgf, 3.6 ft·lbf)
a
T R..
T R..
21
T R..
1
2
1
1

STEERING HEAD
4-52
8. Install:
• Steering stem nut “1”
TIP
Apply the lithium soap base grease to the con-
tact surface of the steering stem nut when in-
stalling.
9. After tightening the nut, check the steering
for smooth movement. If not, adjust the
steering by loosening the steering ring nut
little by little.
10.Adjust:
• Front fork top end “a”11.Tighten:
• Pinch bolt (upper bracket) “1”
• Pinch bolt (lower bracket) “2”
EWA33DD049
WARNING
Tighten the lower bracket to specified
torque. If torqued too much, it may cause
the front fork to malfunction. Steering stem nut
145 Nm (14.5 m·kgf, 105 ft·lbf)
Front fork top end (standard) “a”
5 mm (0.20 in)T R..
a
Upper bracket pinch bolts
21 Nm (2.1 m·kgf, 15 ft·lbf)
Lower bracket pinch bolts
21 Nm (2.1 m·kgf, 15 ft·lbf)
T R..
T R..
21

SWINGARM
4-61
EAS1SM5186REMOVING THE SWINGARM
1. Use a suitable stand to raise the rear wheel
off the ground.
EWA13120
WARNING
Securely support the vehicle so that there is
no danger of it falling over.
2. Measure:
• Swingarm side play
• Swingarm vertical movement
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Measure the tightening torque of the pivot
shaft nut.
b. Measure the swingarm side play “a” by mov-
ing the swingarm from side to side.
c. If the swingarm side play is out of specifica-
tion, check the spacers, the bearings, and
the collars.
d. Check the swingarm vertical movement “b”
by moving the swingarm up and down.
If swingarm vertical movement is not smooth
or if there is binding, check the spacers, the
bearings, and the collars.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
EAS1SM5187REMOVING THE BEARING
1. Remove:
• Bearing “1”
TIP
Remove the bearing by pressing its outer race.
EAS1SM5188CHECKING THE SWINGARM
1. Check:
• Swingarm
Bends/cracks/damage  Replace.
2. Check:
• Pivot shaft
Roll the pivot shaft on a flat surface.
Bends  Replace.
EWA13770
WARNING
Do not attempt to straighten a bent pivot
shaft.
3. Wash with kerosene:
• Pivot shaft
• Spacers
•Collars
• Bearing
4. Check:
• Oil seals
Damage  Replace.
• Bearing
• Spacers
Free play exists/unsmooth revolution/rust 
Replace bearing and bushing as a set. Pivot shaft nut
85 Nm (8.5 m·kgf, 61 ft·lbf)
Swingarm end free play limit (ra-
dial)
1.0 mm (0.04 in)
T R..

CAMSHAFT
5-16
EAS1SM5213CHECKING THE DECOMPRESSION SYS-
TEM
1. Check:
• Decompression system
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Check that the decompressor cam “1”
moves smoothly.
b. Check that the decompressor lever pin “2”
projects from the camshaft.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
EAS1SM5214INSTALLING THE CAMSHAFTS
1. Install:
• Exhaust camshaft “1”
• Intake camshaft “2”
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Turn the crankshaft counterclockwise with a
wrench.
TIP
• Apply molybdenum disulfide oil to the cam-
shafts.
• Apply the engine oil on the decompression
system.
b. Align the top dead center (TDC) mark “a” on
the rotor with the alignment mark “b” on the
crankcase cover.c. Fit the timing chain “3” onto both camshaft
sprockets and install the camshafts on the
cylinder head.
TIP
Make sure that the alignment mark “c” on the
exhaust camshaft sprocket and the alignment
mark “d” on the intake camshaft sprocket are
aligned with the edge of the cylinder head.
ECA33DD029
NOTICE
Do not turn the crankshaft during the cam-
shaft installation. Damage or improper
valve timing will result.
d. Install the clips, the camshaft caps and the
bolts (camshaft cap).
TIP
• Before installing the clips, cover the cylinder
head with a clean cloth to prevent the clips
from coming off into the cylinder head cavity.
• Tighten the bolts to the specified torque in two
or three steps in the proper tightening se-
quence as shown.
ECA33DD030
NOTICE
The bolts (camshaft cap) must be tightened
evenly, or damage to the cylinder head,
camshaft caps, and camshaft will result.
1
2
Bolt (camshaft cap)
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
b
a
dc
3
T R..

CYLINDER HEAD
5-21
EAS1SM5219INSTALLING THE CYLINDER HEAD
1. Install:
• Timing chain guide (intake side) “1”
• Dowel pin “2”
• Cylinder head gasket “3”
• Cylinder head “4”
TIP
• Install the cylinder head gasket with its char-
acter stamp “a” rearward of the vehicle as
shown.
• While pulling up the timing chain, install the
timing chain guide (intake side) and the cylin-
der head.
2. Install:
• Washer “1”
• Cylinder head bolt “2”
• Cylinder head nut “3”
3. Tighten:
• Cylinder head bolt “1” – “4”
• Cylinder head nut “5”, “6”
TIP
• Apply molybdenum disulfide grease to the
threads and contact surfaces of the bolts and
to both contact surfaces of the washers.
• Tighten the bolts and nuts to the specified
torque in two or three steps in the proper tight-
ening sequence as shown.
Cylinder head bolt “1” – “4”
33 Nm (3.3 m·kgf, 24 ft·lbf)
Cylinder head nut “5”, “6”
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
New
12
24
3
a
1
3 22
T R..
15
6
42
3 FWD
x2 x4

CHASSIS
10-6
EAS1SM5379SUSPENSION SETTING (FRONT FORK)
TIP
• If any of the following symptoms is experienced with the standard position as the base, make reset-
ting by reference to the adjustment procedure given in the same chart.
• Before any change, set the rear shock absorber sunken length to the standard figure 90–100 mm
(3.5–3.9 in).
SymptomSection
Check Adjust
JumpLarge
gapMedi-
um
gapSmall
gap
Stiff over entire
rangeCompression
damping forceTurn adjuster counterclock-
wise (about 2 clicks) to de-
crease damping.
Oil amount Decrease oil amount by about
5–10 cm
3 (0.2–0.3 US oz, 0.2–
0.4 Imp.oz).
Spring Replace with soft spring.
Unsmooth
movement over
entire rangeOuter tube
Inner tubeCheck for any bends, dents,
other noticeable scars, etc. If
any, replace affected parts.
Slide metal Replace with a new one for ex-
tended use.
Piston metal Replace with a new one for ex-
tended use.
Lower bracket
tightening
torqueRetighten to specified torque.
Poor initial
movementRebound
damping forceTurn adjuster counterclock-
wise (about 2 clicks) to de-
crease damping.
Oil seals Apply grease in oil seal wall.
Soft over entire
range, bottom-
ing outCompression
damping forceTurn adjuster clockwise (about
2 clicks) to increase damping.
Oil amount Increase oil amount by about
5–10 cm
3 (0.2–0.3 US oz, 0.2–
0.4 Imp.oz).
Spring Replace with stiff spring.
Stiff toward
stroke endOil amountDecrease oil amount by about
5 cm
3 (0.2 US oz, 0.2 Imp.oz).
Soft toward
stroke end, bot-
toming outOil amountIncrease oil amount by about 5
cm
3 (0.2 US oz, 0.2 Imp.oz).
Stiff initial
movementCompression
damping forceTurn adjuster counterclock-
wise (about 2 clicks) to de-
crease damping.