2011 YAMAHA WR 450F torque

2-17
TIGHTENING TORQUES
GENERAL TORQUE
SPECIFICATIONS
This chart specifies torque for stan-
dard fasteners with standard I.S.O.
pitch threads. Torque specifications
for special components or assem-
blies are included in the applicable
sections of this book. To avoid war-
page, tighten multi-fastener assem-
blies in a crisscross fashion, in
progressive stages, until full torque is
reached. Unless otherwise specified,
torque specifications call for clean,
dry threads. Components should be
at room temperature.A. Distance between flats
B. Outside thread diameter
DEFINITION OF UNITS
A
(Nut)B
(Bolt
)TORQUE SPECIFI-
CATION
Nm m•kg ft•lb
10
mm6 mm 6 0.6 4.3
12
mm8 mm 15 1.5 11
14
mm10
mm30 3.0 22
17
mm12
mm55 5.5 40
19
mm14
mm85 8.5 61
22
mm16
mm130 13 94
Unit Read Definition Measure
mm
millimeter 10-3 meter Length
cmcentimeter 10-2 meter Length
kgkilogram 103 gram Weight
NNewton 1 kg × m/sec2Force
NmNewton meter N × m Torque
m•kgMeter kilogram m × kg Torque
PaPascal N/m2Pressure
N/mmNewton per millimeter N/mm Spring rate
LLiter — Volume or capacity
cm3Cubic centimeter — Volume or capacity
r/minRevolution per minute — Engine speed

2-18
TIGHTENING TORQUES

3-27
CHASSIS
4. Adjust:
• Steering ring nut
Steering ring nut adjustment
steps:
a. Remove the headlight.
b. Remove the handlebar and upper
bracket.
c. Loosen the steering ring nut "1"
using the steering nut wrench "2".
d. Tighten the steering ring nut "3"
using steering nut wrench "4".
• Apply the lithium soap base grease
on the thread of the steering stem.
• Set the torque wrench to the steer-
ing nut wrench so that they form a
right angle.
e. Loosen the steering ring nut one
turn.
f. Retighten the steering ring nut us-
ing the steering nut wrench.
Avoid over-tightening.
g. Check the steering stem by turn-
ing it lock to lock. If there is any
binding, remove the steering stem
assembly and inspect the steer-
ing bearings.
h. Install the washer "5", upper
bracket "6", washer "7", steering
stem nut "8", handlebar "9", han-
dlebar upper holder "10" and
headlight "11".
• The handlebar upper holder should
be installed with the punched mark
"a" forward.
• Install the handlebar so that the
marks "b" are in place on both
sides.
• Install the handlebar so that the pro-
jection "c" of the handlebar upper
holder is positioned at the mark on
the handlebar as shown.
• Insert the end of the fuel breather
hose "12" into the hole in the steer-
ing stem.
First tighten the bolts on the front
side of the handlebar upper holder,
and then tighten the bolts on the
rear side.
Steering nut wrench:
YU-33975/90890-01403
Steering nut wrench:
YU-33975/90890-01403
Steering ring nut (initial
tightening):
38 Nm (3.8 m•kg, 27
ft•lb)
Steering ring nut (final
tightening):
7 Nm (0.7 m•kg, 5.1
ft•lb)
Steering stem nut:
145 Nm (14.5 m•kg, 105
ft•lb)
Handlebar upper holder:
28 Nm (2.8 m•kg, 20
ft•lb)
Pinch bolt (upper brack-
et):
21 Nm (2.1 m•kg, 15
ft•lb)
Headlight:
7 Nm (0.7 m•kg, 5.1
ft•lb)

4-9
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
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.
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.
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 installing 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.
Replace the titanium valves with the
cylinder head.
Refer to "CHECKING THE
VALVE".
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 TIP.
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)