torque YAMAHA WR 450F 2008 User Guide

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 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
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 torqueRetighten 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).

5-19
CAMSHAFTS
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",
the timing chain tensioner "2", and
the gasket "3", and tighten the bolt
"4" to the specified torque.
c. Release the screwdriver, check
the tensioner rod to come out and
tighten the gasket "5" and the cap
bolt "6" to the specified torque.
3. Turn:
• Crankshaft
Counterclockwise several turns.4. Check:
• Rotor T.D.C. mark
Align with the crankcase align
mark.
• Camshaft match marks
Align with the cylinder head sur-
face.
Out of alignment→Adjust.
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)

5-21
CYLINDER HEAD
CHECKING THE CYLINDER HEAD
1. Eliminate:
• Carbon deposits (from the com-
bustion chambers)
Use a rounded scraper.
Do not use a sharp instrument to
avoid damaging or scratching:
• Spark plug threads
• Valve seats
2. Inspect:
• Cylinder head
Scratches/damage→Replace.
3. Measure:
• Cylinder head warpage
Out of specification→Resurface.
Warpage measurement and resur-
facing steps:
a. Place a straightedge and a feeler
gauge across the cylinder head.
b. Use a feeler gauge to measure
the warpage.
c. If the warpage is out of specifica-
tion, resurface the cylinder head.
d. Place a 400–600 grit wet sandpa-
per on the surface plate, and re-
surface the head using a figure-
eight sanding pattern.
To ensure an even surface rotate the
cylinder head several times.
INSTALLING THE CYLINDER
HEAD
1. Install:
• Timing chain guide (exhaust side)
"1"
• Dowel pin "2"
• Cylinder head gasket "3" • Cylinder head "4"
While pulling up the timing chain, in-
stall the timing chain guide (exhaust
side) and cylinder head.
2. Install:
• Washer "1"
• Bolts "2"
Installation steps:
Tighten the cylinder head using
the rotation angle procedure to ob-
tain uniform tightening torque.
a. Wash the threads and contact
surfaces of the bolts, the contact
surfaces of the plain washers, the
contact surface of the cylinder
head, and the threads of the
crankcase.
b. Apply the molybdenum disulfide
grease on the threads and con-
tact surfaces of the bolts and on
both contact surfaces of the plain
washers.
c. Install the plain washers and
bolts.
d. Tighten the bolts to the specified
torque in two or three steps in the
proper tightening sequence as
shown.e. Remove the bolts.
f. Again apply the molybdenum dis-
ulfide grease on the threads and
contact surfaces of the bolts and
on both contact surfaces of the
plain washers.
g. Retighten the bolts.
Tighten the bolts to the specified
torque in two or three steps in the
proper tightening sequence as
shown.
h. Put a mark on the corner "1" of the
bolt (cylinder head) and the cylin-
der head "2" as shown.
Tighten the bolts 90° in each of the
two steps to reach the specified angle
of 180° in the proper tightening se-
quence as shown.
Cylinder head warpage:
Less than 0.05 mm
(0.002 in)
Bolts (cylinder head):
1st:
30 Nm (3.0 m•kg, 22
ft•lb)
Bolts (cylinder head):
2nd:
20 Nm (2.0 m•kg, 14
ft•lb)
Bolts (cylinder head):
Final:
Specified angle 180°

5-48
AC MAGNETO AND STARTER CLUTCH
AC MAGNETO AND STARTER CLUTCH
REMOVING THE AC MAGNETO AND STARTER CLUTCH
Order Part name Q'ty Remarks
Drain the engine oil.Refer to "CHANGING THE ENGINE OIL"
section in the CHAPTER 3.
Seat and fuel tankRefer to "REMOVING THE SEAT, FUEL
TANK AND SIDE COVERS" section in the
CHAPTER 3.
Disconnect the AC magneto lead.
1 Shift pedal 1
2 Cover (torque limiter) 1
3 Torque limiter 1 Do not disassemble.
4 Crankcase cover (left) 1
5 Gasket 1
6 Dowel pin 2
7 Idle gear 1
8 Bearing 1
9Shaft 1
10* Nut (rotor) 1 Refer to NOTE.
11 Rotor 1 Refer to removal section.

5-50
AC MAGNETO AND STARTER CLUTCH
REMOVING THE ROTOR
1. Remove:
• Nut (rotor) "1"
• Washer
Use the sheave holder "2".
2. Remove:
• Rotor "1"
Use the rotor puller "2".
REMOVING THE STARTER
CLUTCH
1. Remove:
• Starter clutch assembly cover "1"
Insert a thin screwdriver or the like
under the convexity "a" and remove
the starter clutch assembly cover by
prying it gently to void damage to the
cover.
2. Remove:
• Starter clutch "1"
Using a thin screwdriver or the like,
remove the plate "a" while prying it
upward little by little.
CHECKING THE AC MAGNETO
1. Inspect:
• Rotor inner surface "a"
• Stator outer surface "b"
Damage→Inspect the crankshaft
runout and crankshaft bearing.
If necessary, replace AC magneto
and/or stator.
CHECKING THE WOODRUFF KEY
1. Inspect:
• Woodruff key "1"
Damage→Replace.
CHECKING THE STARTER
CLUTCH
1. Check:
• Starter clutch
Damage/wear→Replace.
2. Check:
• Idle gear
• Idle gear shaft
• Starter clutch drive gear
Pitting/burrs/chips/roughness/
wear→Replace the defective
parts.
3. Check:
• Starter clutch operation
a. Install the starter clutch drive gear
"1" onto the starter clutch "2" and
hold the starter clutch.b. When turning the starter clutch
drive gear counterclockwise "B",
the starter clutch and the starter
clutch drive gear should engage.
If the starter clutch drive gear and
starter clutch do not engage, the
starter clutch is faulty and must be
replaced.
c. When turning the starter clutch
drive gear clockwise "A", it should
turn freely. If the starter clutch
drive gear does not turn freely, the
starter clutch is faulty and must be
replaced.
CHECKING THE TORQUE LIMITER
1. Check:
• Torque limiter
Damage/wear→Replace.
INSTALLING THE AC MAGNETO
AND STARTER CLUTCH
1. Install:
• Stator "1"
• Bolt (stator) "2"
• Pickup coil "3"
• Holder "4"
• Bolt (pickup coil) "5" Sheave holder:
YS-1880-A/90890-
01701
Rotor puller:
YM-04142/90890-04142
Bolt (stator):
7 Nm (0.7 m•kg, 5.1
ft•lb)
Bolt (pickup coil):
10 Nm (1.0 m•kg, 7.2
ft•lb)

5-51
AC MAGNETO AND STARTER CLUTCH
• Pass the AC magneto lead "5" un-
der the pickup coil.
• Pass the AC magneto lead "4" un-
der the holder as shown.
• Take care not to catch the AC mag-
neto lead between crankcase cover
ribs.
• Tighten the bolt (stator) using the
T25 bit.
• Apply the sealant to the grommet of
the AC magneto lead.
2. Install:
• Starter clutch drive gear "1"
Apply the engine oil on the starter
clutch drive gear inner circumference.
3. Install:
• Starter clutch "1"
To rotor "2".
• Install the starter clutch with its
plate side upward.
• While installing the starter clutch,
push in the projections "a" one by
one on the clutch circumference.
• Push in the starter clutch until it hits
the rotor.
4. Install:
• Starter clutch assembly cover "1"
To rotor "2".
Install the starter clutch assembly
cover by fitting its pawls "a" into the
groove "b" in the rotor.
5. Install:
• Woodruff key "1"
• Rotor "2"
• Degrease the contact surfaces of
the tapered portions of the crank-
shaft and rotor.
• When installing the woodruff key,
make sure that its flat surface "a" is
in parallel with the crankshaft center
line "b".
• When installing the rotor, align the
keyway "c" of the rotor with the
woodruff key.
6. Install:
• Washer (rotor)
• Nut (rotor) "1"
Use the sheave holder "2"
Tighten the rotor nut to 65 Nm (6.5
m•kg, 47 ft•lb), loosen and retighten
the rotor nut to 65 Nm (6.5 m•kg, 47
ft•lb).
7. Install:
• Shaft "1"
• Bearing "2"
• Idle gear 2 "3"
Apply the engine oil on the shaft,
bearing and idle gear inner circumfer-
ence.
8. Install:
• Dowel pin
• Gasket [crankcase cover (left)]
• Crankcase cover (left) "1"
• Bolt [crankcase cover (left)]
Tighten the bolts in stage, using a
crisscross pattern.
9. Install:
• Washer "1"
• Torque limiter "2"
• Washer
Apply the engine oil to the shaft and
washers.
10. Install:
• Cover (idle gear 1) "1"
•Bolt "2" YAMAHA Bond No. 1215
(ThreeBond
® No. 1215):
90890-85505
Nut (rotor):
65 Nm (6.5 m•kg, 47
ft•lb)
Sheave holder:
YS-1880-A/90890-
01701
Bolt [crankcase cover
(left)]:
10 Nm (1.0 m•kg, 7.2
ft•lb)
Bolt:
10 Nm (1.0 m•kg, 7.2
ft•lb)

6-21
FRONT FORK
Be sure to install the spring guide "2"
when checking the oil level.
Never fail to make the oil level ad-
justment between the maximum
and minimum level and always ad-
just each front fork to the same
setting. Uneven adjustment can
cause poor handling and loss of
stability.
21. Measure:
• Distance "a"
Out of specification→Turn into
the locknut.
22. Loosen:
• Rebound damping adjuster "1"
• Loosen the rebound damping ad-
juster finger tight.
• Record the set position of the ad-
juster (the amount of turning out the
fully turned in posi-tion).
23. Install:
• Push rod "1"
• Fork spring "2"
• Install the fork spring with the
damper rod "3" pulled up.
• After installing the fork spring, hold
the damper rod end so that it will not
go down.
24. Install:
• Spring seat "1"
• Front fork cap bolt "2"
Fully finger tighten the front fork cap
bolt onto the damper rod.
25. Tighten:
• Front fork cap bolt (locknut) "1"
Hold the locknut "2" and tighten the
front fork cap bolt with specified
torque.
26. Install:
• Front fork cap bolt "1"
To outer tube.
Temporarily tighten the cap bolt.
27. Install:
• Protector guide "1"
Install the protector guide with its wid-
er side "a" facing downward.
INSTALLING THE FRONT FORK
1. Install:
• Front fork "1"
• Temporarily tighten the pinch bolts
(lower bracket).
• Do not tighten the pinch bolts (up-
per bracket) yet.
2. Tighten:
• Front fork cap bolt Distance "a":
18 mm (0.71 in) or more
Between damper rod
"1" top and locknut "2"
top.
Front fork cap bolt (lock-
nut):
29 Nm (2.9 m•kg, 21
ft•lb)
Front fork cap bolt:
30 Nm (3.0 m•kg, 22
ft•lb)

6-22
FRONT FORK
3. Adjust:
• Front fork top end "a"
4. Tighten:
• Pinch bolt (upper bracket) "1"
• Pinch bolt (lower bracket) "2"
Tighten the lower bracket to speci-
fied torque. If torqued too much, it
may cause the front fork to mal-
function.
5. Install:
• Speed sensor lead "1"
• Plate 1 "2"
• Bolt (plate 1) "3"
To right protector "4".
Install the speed sensor lead so that
its paint "a" directs as shown and
align the bottom "b" of the plate 1 with
the same paint.
6. Install:
• Speed sensor lead "1"
•Plate 2 "2"
• Screw (plate 2) "3"
To right protector "4".
Install the plate 2 in the direction as
shown.
7. Install:
• Protector "1"
• Bolt (protector) "2"
8. Adjust:
• Rebound damping force
Turn in the damping adjuster "1" fin-
ger-tight and then turn out to the orig-
inally set position.
Front fork top end (stan-
dard) "a":
Zero mm (Zero in)
Pinch bolt (upper brack-
et):
21 Nm (2.1 m•kg, 15
ft•lb)
Pinch bolt (lower brack-
et):
21 Nm (2.1 m•kg, 15
ft•lb)
Bolt (plate 1):
4 Nm (0.4 m•kg, 2.9 ft •
lb)
Screw (plate 2):
0.5 Nm (0.05 m•kg, 0.36
ft•lb)
Bolt (protector):
7 Nm (0.7 m•kg, 5.1
ft•lb)

6-30
STEERING
6. Install:
• Washer "1"
7. Install:
• Front fork "1"
• Upper bracket "2"
• Main switch "3"
• Front brake hose guide bracket
"4"
• Temporarily tighten the pinch bolts
(lower bracket).
• Do not tighten the pinch bolts (up-
per bracket) yet.
8. Install:
• Guide (speed sensor lead) "1"
After installing the guide as shown,
pass the speed sensor lead through
the guide.
9. Install:
• Washer "1"
• Steering stem nut "2"10. After tightening the nut, check the
steering for smooth movement. If
not, adjust the steering by loosen-
ing the steering ring nut little by lit-
tle.
11. Adjust:
• Front fork top end "a"
12. Tighten:
• Pinch bolt (upper bracket) "1"
• Pinch bolt (lower bracket) "2"
Tighten the lower bracket to speci-
fied torque. If torqued too much, it
may cause the front fork to mal-
function.
13. Install:
• Multi-function display bracket "1"
• Multi-function display "2"
Pass the throttle cables "3", clutch ca-
ble "4" and hot starter cable "5" be-
tween the multi-function display
bracket and upper bracket.
14. Install:
• Holder "1"
• Clamp "2"
• Install so that the marking "a" on the
speed sensor lead aligns with the
holder edge.
• Fasten the speed sensor lead to the
holder with the clamp.
Steering stem nut:
145 Nm (14.5 m•kg, 105
ft•lb)
Front fork top end (stan-
dard) "a":
Zero mm (Zero in)
Pinch bolt (upper brack-
et):
21 Nm (2.1 m•kg, 15
ft•lb)
Pinch bolt (lower brack-
et):
21 Nm (2.1 m•kg, 15
ft•lb)
Multi-function display
bracket:
7 Nm (0.7 m•kg, 5.1
ft•lb)
Multi-function display:
4 Nm (0.4 m•kg, 2.9
ft•lb)
Holder:
13 Nm (1.3 m•kg, 9.4
ft•lb)
Clamp:
7 Nm (0.7 m•kg, 5.1
ft•lb)