2008 YAMAHA WR 250F lock

4-8
CHASSIS
SUSPENSION SETTING (FRONT FORK)
• If any of the following symptoms is experienced with the standard position as the base, make resetting by reference to the adjustment procedure gi ven in the same chart.
• Before any change, set t he rear shock absorber sunken length to the standard figure 90–100 mm (3.5–3.9 in).
SymptomSection
Check Adjust
Jump Large
gap Medi-
um
gap Small
gap
Stiff over entire
range ○○○ Compression damping Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Oil level (oil amount) Decrease oil level by about 5–10 mm (0.2–0.4 in).
Spring Replace with soft spring.
Unsmooth move-
ment over entire
range ○○○○ Outer tube
Check for any bends, dents, and other noticeable
scars, etc. If any, replace affected parts.
Inner tube
Under bracket tighten-
ing torque Retighten to specified torque.
Poor initial move-
ment ○Rebound damping Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Oil seal Apply grease in oil seal wall.
Soft over entire
range, bottoming
out ○○ Compression damping Turn adjuster clockwise (about 2 clicks) to in-
crease damping.
Oil level (oil amount) Increase oil level by about 5–10 mm (0.2–0.4 in).
Spring Replace with stiff spring.
Stiff toward stroke
end ○
Oil level (oil amount) Decrease oil level by about 5 mm (0.2 in).
Soft toward stroke
end, bottoming out ○
Oil level (oil amount) Increase oil level by about 5 mm (0.2 in).
Stiff initial move-
ment ○○○○
Compression dampingTurn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Low front, tending to
lower front posture ○○Compression damping Turn adjuster clockwise (about 2 clicks) to in-
crease damping.
Rebound damping Turn adjuster counterclockwise (about 2 clicks) to decrease damping.
Balance with rear end Set sunken length for 95–100 mm (3.7–3.9 in) when one passenger is astride seat (lower rear
posture).
Oil level (oil amount) Increase oil level by about 5 mm (0.2 in).
"Obtrusive" front,
tending to upper
front posture ○○Compression damping Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Balance with rear end Set sunken length for 90–95 mm (3.5–3.7 in) when one passenger is astride seat (upper rear
posture).
Spring Replace with soft spring.
Oil level (oil amount) Decrease oil level by about 5–10 mm (0.2–0.4 in).

4-9
CHASSIS
SUSPENSION SETTING (REAR SHOCK ABSORBER)
• If any of the following symptoms is experienced with the standard position as the base, make resetting by reference to the adjustment procedure gi ven in the same chart.
• Adjust the rebound damping in 2-click increments or decrements.
• Adjust the low compression damping in 1-click increments or decrements.
• Adjust the high compression damping in 1/6 turn increments or decrements.
Symptom Section
Check Adjust
Jump Large
gap Medi-
um
gap Small
gap
Stiff, tending to sink ○○Rebound damping Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Spring set length Set sunken length for 90–100 mm (3.5–3.9 in) when one passenger is astride seat.
Spongy and unsta-
ble ○○Rebound damping Turn adjuster clockwise (about 2 clicks) to in-
crease damping.
Low compression
damping Turn adjuster clockwise (about 1 click) to increase
damping.
Spring Replace with stiff spring.
Heavy and dragging ○○Rebound damping Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Spring Replace with soft spring.
Poor road gripping ○Rebound damping Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Low compression
damping Turn adjuster clockwise (about 1 clicks) to in-
crease damping.
High compression
damping Turn adjuster clockwise (about 1/6 turn) to in-
crease damping.
Spring set length Set sunken length for 90–100 mm (3.5–3.9 in) when one passenger is astride seat.
Spring Replace with soft spring.
Bottoming out ○○ High compression
damping
Turn adjuster clockwise (about 1/6 turn) to in-
crease damping.
Spring set length Set sunken length for 90–100 mm (3.5–3.9 in) when one passenger in astride seat.
Spring Replace with stiff spring.
Bouncing ○○ Rebound damping Turn adjuster clockwise (about 2 clicks) to in-
crease damping.
Spring Replace with soft spring.
Stiff travel ○○ High compression
damping
Turn adjuster counterclockw
ise (about 1/6 turn) to
decrease damping.
Spring set length Set sunken length for 90–100 mm (3.5–3.9 in) when one passenger is astride seat.
Spring Replace with soft spring.

5-3
RADIATOR
HANDLING NOTE
Do not remove the radiator cap
when the engine and radiator are
hot. Scalding hot fluid and steam
may be blown out under pressure,
which could cause serious injury.
When the engine has cooled, open
the radiator cap by the following
procedure:
Place a thick rag, like a towel, over
the radiator cap, slowly rotate the
cap counterclockwise to the de-
tent. This procedure allows any re-
sidual pressure to escape. When
the hissing sound has stopped,
press down on the cap while turn-
ing counterclockwise and remove
it.
CHECKING THE RADIATOR
1. Inspect:• Radiator core "1"
Obstruction →Blow out with com-
pressed air through rear of the ra-
diator.
Bent fin →Repair/replace.
INSTALLING THE RADIATOR
1. Install: • O-ring "1"
• Radiator pipe 1 "2"
• Bolt (radiator pipe) "3"
Apply the lithium soap base grease
on the O-ring.
2. Install:• Catch tank hose "1"
• Radiator hose 2 "2"
• Radiator hose 3 "3"
• Radiator pipe 2 "4"
• Radiator hose 5 "5"
• Radiator hose 4 "6"To right radiator "7".
3. Install: • Right radiator "1"
• Bolt (right radiator) "2"
• Radiator hose 5 "3"
Refer to "CABLE ROUTING DIA-
GRAM" section in the CHAPTER
2.
4. Install: • Left radiator "1"
• Bolt (left radiator) "2"
• Radiator hose 1 "3"
Refer to "CABLE ROUTING DIA-
GRAM" section in the CHAPTER
2.
5. Tighten:
• Radiator hose clamp "4" 6. Install:
• Radiator guard "1"
First fit the inner hook portion "a" and
then the outer one "b" onto the radia-
tor.
7. Install:• Catch tank "1"
• Bolt (catch tank) "2"
• Bolt (catch tank) "3"
• Catch tank hose "4"
• Catch tank breather hose "5"Refer to "CABLE ROUTING DIA-
GRAM" section in the CHAPTER
2.
Bolt (radiator pipe): 10 Nm (1.0 m•kg, 7.2
ft•lb)
Bolt (right radiator):10 Nm (1.0 m•kg, 7.2
ft•lb)
Bolt (left radiator): 10 Nm (1.0 m•kg, 7.2
ft•lb)
Radiator hose 1: 2 Nm (0.2 m•kg, 1.4
ft•lb)
Radiator hose clamp: 2 Nm (0.2 m•kg, 1.4
ft•lb)
Bolt (catch tank):
7 Nm (0.7 m•kg, 5.1
ft•lb)
Bolt (catch tank): 16 Nm (1.6 m•kg, 11
ft•lb)

5-16
CAMSHAFTS
REMOVING THE CAMSHAFT
1. Remove:• Timing mark accessing screw "1"
• Crankshaft end accessing screw
"2"
2. Align: • T.D.C. markWith align mark.
Checking steps:
a. Turn the crankshaft counterclock-
wise with a wrench.
b. Align the T.D.C. mark "a" on the rotor with the align mark "b" on the
crankcase cover when piston is at
T.D.C. on compression stroke.
In order to be sure t hat the piston is at
Top Dead Center, the punch mark "c"
on the exhaust camshaft and the
punch mark "d" on the intake cam-
shaft must align with the cylinder
head surface, as shown in the illustra-
tion.
3. Remove: • Timing chain tensioner cap bolt
"1"
• Timing chain tensioner "2"
• Gasket 4. Remove:
• Bolt (camshaft cap) "1"
• Camshaft cap "2"
• Clip
Remove the bolts (camshaft cap) in a
crisscross pattern, working from the
outside in.
The bolts (camshaft cap) must be
removed evenly to prevent dam-
age to the cylinder head, cam-
shafts or camshaft caps.
5. Remove:• Exhaust camshaft "1"
• Intake camshaft "2"
Attach a wire "3" to the timing chain to
prevent it from falling into the crank-
case.
CHECKING THE CAMSHAFT
1. Inspect:• Cam lobe
Pitting/scratches/blue discolora-
tion →Replace.
2. Measure:
• Cam lobe length "a" and "b"Out of specification →Replace. 3. Measure:
• Runout (camshaft)Out of specification →Replace.
4. Measure: • Camshaft-to-cap clearance
Out of specification →Measure
camshaft outside diameter.
Cam lobes length: Intake "a":29.65–29.75 mm
(1.1673–1.1713 in)
: 29.55 mm (1.1634 in)
Intake "b": 22.45–22.55 mm
(0.8839–0.8878 in)
: 22.35 mm (0.8799 in)
Exhaust "a":
30.399–30.499 mm
(1.1968–1.2007 in)
:
30.299 mm (1.1929 in)
Exhaust "b": 22.45–22.55 mm
(0.8839–0.8878 in)
: 22.35 mm (0.8799 in)
Runout (camshaft): Less than 0.03 mm
(0.0012 in)

5-17
CAMSHAFTS
Measurement steps:
a. Install the camshaft onto the cylin-der head.
b. Position a strip of Plastigauge
®
"1" onto the camshaft.
c. Install the clip, dowel pins and camshaft caps.
• Tighten the bolts (camshaft cap) in a crisscross pattern from innermost
to outer caps.
• Do not turn the camshaft when measuring clearance with the Plas-
tigauge
®.
d. Remove the camshaft caps and
measure the width of the Plasti-
gauge
® "1".
5. Measure:• Camshaft outside diameter "a"Out of specification →Replace the
camshaft.
Within specification →Replace
camshaft case and camshaft
caps as a set. CHECKING THE CAMSHAFT
SPROCKET
1. Inspect:
• Camshaft sprocket "1"Wear/damage →Replace the
camshaft assemb ly and timing
chain as a set.
CHECKING THE
DECOMPRESSION SYSTEM
1. Check: • Decompression system
Checking steps:
a. Check that the decompression
mechanism cam "1" moves
smoothly.
b. Check that the decompression
mechanism cam lever pin "2"
projects from the camshaft.
CHECKING THE TIMING CHAIN
TENSIONER
1. Check:• While pressing the tensioner rod lightly with fingers, use a thin
screwdriver "1" and wind the ten-
sioner rod up fully clockwise.
• When releasing the screwdriver
by pressing lightly with fingers,
make sure that the tensioner rod
will come out smoothly.
• If not, replace the tensioner as- sembly. INSTALLING THE CAMSHAFT
1. Install:
• Exhaust camshaft "1"
• Intake camshaft "2"
Installation steps:
a. Turn the crankshaft counterclock- wise with a wrench.
• Apply the molybdenum disulfide oil on the camshafts.
• Apply the engine oil on the decom- pression system.
• Squeezing the decompression le-
ver allows the crankshaft to be
turned easily.
b. Align the T.D.C. mark "a" on the rotor with the align mark "b" on the
crankcase cover when piston is at
T.D.C. on compression stroke.
c. Fit the timing chain "3" onto both camshaft sprockets and install the
camshafts on the cylinder head.
Camshaft-to-cap clear-
ance:
0.028–0.062 mm
(0.0011–0.0024 in)
:0.08 mm (0.003
in)
Bolt (camshaft cap): 10 Nm (1.0 m•kg, 7.2
ft•lb)
Camshaft outside diame-
ter: 21.959–21.972 mm
(0.8645–0.8650 in)

5-18
CAMSHAFTS
The camshafts should be installed
onto the cylinder head so that the
punch mark "c" on the exhaust cam-
shaft and the punch mark "d" on the
intake camshaft must align with the
cylinder head surface, as shown in
the illustration.
Do not turn the crankshaft during
the camshaft installation. Damage
or improper valve timing will re-
sult.
d. Install the clips, camshaft caps "4"
and bolts (camshaft cap) "5".
• Before removing the clips, cover the cylinder head with a clean rag to
prevent the clips from into the cylin-
der head cavity.
• Apply the molybdenum disulfide oil on the thread of the bolts (camshaft
cap).
• Tighten the bolts to the specified torque in two or three steps in the
proper tightening sequence as
shown.
The bolts (camshaft cap) must be
tightened evenly, or damage to the
cylinder head, camshaft caps, and
camshaft will result.
2. Install:• Timing chain tensioner
Installation steps:
a. While pressing the tensioner rod lightly with fingers, use a thin
screwdriver and wind the tension-
er rod up fully clockwise.
b. With the rod fully wound and the chain tensioner UP mark "a" fac-
ing upward, install the gasket "1"
and the timing chain tensioner "2",
and tighten the bolt "3" to the
specified torque.
c. Release the screwdriver, check the tensioner rod to come out and
tighten the gasket "4" and the cap
bolt "5" to the specified torque.
3. Turn:
• CrankshaftCounterclockwise several turns.
4. Check:
• Rotor T.D.C. markAlign with the crankcase align
mark.
• Camshaft match marks Align with the cylinder head sur-
face.
Out of alignment →Adjust. 5. Install:
• Timing mark accessing screw "1"
• Crankshaft end accessing screw "2"
6. Install: • Timing chain guide (top side) "1"
• Cylinder head cover gasket "2"
• Cylinder head cover "3"
• Bolt (cylinder head cover) "4"
Apply the sealant on the cylinder
head cover gasket.
7. Install:• Cylinder head breather hose
• Spark plug
Bolt (camshaft cap):
10 Nm (1.0 m•kg, 7.2
ft•lb)
Bolt (timing chain ten-
sioner):10 Nm (1.0 m•kg, 7.2
ft•lb)
Tensioner cap bolt: 7 Nm (0.7 m•kg, 5.1
ft•lb)
Bolt (cylinder head cov-
er): 10 Nm (1.0 m•kg, 7.2
ft•lb)
YAMAHA Bond No. 1215
(ThreeBond
® No. 1215):
90890-85505
Spark plug: 13 Nm (1.3 m•kg, 9.4
ft•lb)

5-30
CLUTCH
14 Nut (clutch boss)1 Refer to removal section.
15 Lock washer 1 Refer to removal section.
16 Clutch boss 1 Refer to removal section.
17 Thrust washer 1
18 Primary driven gear 1
19 Push lever shaft 1
Order
Part name Q'tyRemarks

5-31
CLUTCH
REMOVING THE CLUTCH BOSS
1. Remove:•Nut "1"
• Lock washer "2"
• Clutch boss "3"
Straighten the lock washer tab and
use the clutch holding tool "4" to hold
the clutch boss.
A. For USA and CDN
B. Except for USA and CDN
CHECKING THE CLUTCH
HOUSING AND BOSS
1. Inspect: • Clutch housing "1"
Cracks/wear/damage →Replace.
• Clutch boss "2" Scoring/wear/damage →Replace.
CHECKING THE PRIMARY DRIVEN
GEAR
1. Check: • Circumferential play
Free play exists →Replace.
• Gear teeth "a" Wear/damage →Replace. CHECKING THE CLUTCH
SPRINGS
1. Measure:
• Clutch spring free length "a"
Out of specification →Replace
springs as a set.
CHECKING THE FRICTION
PLATES
1. Measure: • Friction plate thickness
Out of specification →Replace
friction plate as a set.
Measure at all four points.
CHECKING THE CLUTCH PLATES
1. Measure: • Clutch plate warpageOut of specification →Replace
clutch plate as a set.
Use a surface plate "1" and thick-
ness gauge "2". CHECKING THE PUSH LEVER
SHAFT
1. Inspect:
• Push lever shaft "1"
Wear/damage →Replace.
CHECKING THE PUSH ROD
1. Inspect: • Push rod 1 "1"
• Bearing "2"
• Washer "3"
• Push rod 2 "4"
•Ball "5"Wear/damage/bend →Replace.
INSTALLING THE PUSH LEVER
SHAFT
1. Install: • Push lever shaft "1"
• Bolt (push lever shaft) "2"
• Apply the lithium soap base grease
on the oil seal lip.
• Apply the engine oil on the push le- ver shaft.
• Fit the seat plate "3" in the groove "a" of the push lever shaft and tight-
en the bolt (seat plate).
INSTALLING THE CLUTCH
1. Install:• Primary driven gear "1"
• Thrust washer "2"
• Clutch boss "3"
Clutch holding tool:
YM-91042/90890-04086
Clutch spring free
length:
37.0 mm (1.46 in)
: 36.0 mm (1.42
in)
Friction plate thickness: 2.9–3.1 mm (0.114–
0.122 in)
: 2.7 mm (0.106
in)
Warp limit: 0.1 mm (0.004 in)
Bolt (push lever shaft): 10 Nm (1.0 m•kg, 7.2
ft•lb)