torque YAMAHA YZ450F 2004 User Guide

4 - 14
ENG
CARBURATEUR
VERGASER
Choke-Schieber
1. Kontrollieren:
Kaltstarter-Tauchkolben 1
Heißstarter-Tauchkolben 2
Verschleiß/Beschädigung → Erneuern.
Beschleunigungspumpe
1. Kontrollieren:
Membran (Beschleunigungspumpe) 1
Feder 2
Deckel 3
O-Ring 4
Druckstange 5
Rißbildung (Membran)/Beschädigung →
Erneuern.
Schmutz → Säubern.
2. Inspizieren:
Drosselwelle 1
Feder 2
Hebel 1 3
Feder 1 4
Hebel 2 5
Feder 2 6
Schmutz → Säubern.
ZUSAMMENBAU UND MONTAGE
Vergaser
1. Montieren:
Kaltstarter-Tauchkolben 1
2. Montieren:
Leerlaufluftdüse 1 Plongeur de starter
1. Contrôler:
Plongeur de démarrage à froid 1
Plongeur de démarrage à chaud 2
Usure/endommagement → Remplacer.
Pompe d’accélérateur
1. Contrôler:
Diaphragme (pompe d’accélérateur) 1
Ressort 2
Couvercle 3
Joint torque 4
Tige de commande 5
Déchirure (diaphragme)/endommagement
→ Remplacer.
Sale → Nettoyer.
2. Inspecter:
Axe de papillon 1
Ressort 2
Levier 1 3
Ressort 1 4
Levier 2 5
Ressort 2 6
Sale → Nettoyer.
ASSEMBLAGE ET MONTAGE
Carburateur
1. Monter:
Plongeur de démarrage à froid 1
2. Monter:
Gicleur d’air de ralenti 1

4 - 28
ENG
With the rod fully wound and the chain
tensioner UP mark a facing upward,
install the gasket 1 and the chain ten-
sioner 2, and tighten the bolt 3 to the
specified torque.
T R..
Bolt (timing chain tensioner):
10 Nm (1.0 m • kg, 7.2 ft • lb)
Release the screwdriver, check the ten-
sioner rod to come out and tighten the
gasket 4 and the cap bolt 5 to the speci-
fied torque.
T R..
Tensioner cap bolt:
7 Nm (0.7 m • kg, 5.1 ft • lb)
5
4New
3. Turn:
Crankshaft
Counterclockwise several turns
4. Check:
Rotor “I” mark
Align with the crankcase stationary
pointer.
Camshaft match marks
Align with the cylinder head surface.
Out of alignment → Adjust.
CAMSHAFTS

4 - 31
ENGCYLINDER HEAD
ASSEMBLY AND INSTALLATION
1. Install:
Timing chain guide (front) 1
Dowel pin 2
Cylinder head gasket 3
Cylinder head 4
NOTE:
While pulling up the timing chain, install the
timing chain guide (front) and cylinder head.
New
2. Install:
Plain washer 1
Bolt [L=160 mm (6.30 in)] 2
Bolt [L=150 mm (5.91 in)] 3
Installation steps:
CAUTION:
Tighten the cylinder head using the rota-
tion angle procedure to obtain uniform
tightening torque.
Wash the threads and contact surfaces of
the bolts, the contact surfaces of the plain
washers, the contact surface of the cylin-
der head, and the threads of the crank-
case.
Apply the molybdenum disulfide grease on
the threads and contact surfaces of the
bolts and on both contact surfaces of the
plain washers.
Install the plain washers and bolts.
Tighten the bolts to the specified torque in
two or three steps in the proper tightening
sequence as shown.
T R..
Bolts (cylinder head):
1st:
30 Nm (3.0 m • kg, 22 ft • lb)

4 - 32
ENG
Remove the bolts.
Again apply the molybdenum disulfide
grease on the threads and contact sur-
faces of the bolts and on both contact sur-
faces of the plain washers.
Retighten the bolts.
NOTE:
Tighten the bolts to the specified torque in
two or three steps in the proper tightening
sequence as shown.
T R..
Bolts (cylinder head):
2nd:
20 Nm (2.0 m • kg, 14 ft • lb)
Put a mark on the corner 1 of the bolt
(cylinder head) and the cylinder head 2
as shown.
NOTE:
Tighten the bolts 90˚ in each of the two
steps to reach the specified angle of 180˚ in
the proper tightening sequence as shown.
T R..
Bolts (cylinder head):
Final:
Specified angle 180˚
1
2
180˚
3. Install:
Cable guide 1
Nut (cylinder head) 2
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
4. Install:
Copper washer 1
Oil delivery pipe 2
Union bolt (M8) 3
Union bolt (M10) 4
New
T R..18 Nm (1.8 m · kg, 13 ft · lb)
T R..20 Nm (2.0 m · kg, 14 ft · lb)
CYLINDER HEAD

5 - 36
CHASFRONT FORK
21. Measure:
Distance a
Out of specification → Turn into the
locknut.
Distance a:
19 mm (0.75 in) or more
Between damper rod 1 top and
locknut 2 top.
22. Loosen:
Rebound damping adjuster 1
NOTE:
Loosen the rebound damping adjuster finger
tight.
Record the set position of the adjuster (the
amount of turning out the fully turned in posi-
tion).
23. Install:
Push rod 1
Fork spring 2
NOTE:
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
Cap bolt 2
NOTE:
Fully finger tighten the cap bolt onto the
damper rod.
25. Tighten:
Cap bolt (locknut) 1
NOTE:
Hold the locknut 2 and tighten the cap bolt
with specified torque.
T R..29 Nm (2.9 m · kg, 21 ft · lb)

5 - 37
CHASFRONT FORK
26. Install:
Cap bolt 1
To outer tube.
NOTE:
Temporarily tighten the cap bolt.
27. Install:
Protector guide 1
Installation
1. Install:
Front fork 1
NOTE:
Temporarily tighten the pinch bolts (under
bracket).
Do not tighten the pinch bolts (handle crown)
yet.
2. Tighten:
Cap bolt 1
3. Adjust:
Front fork top end a
4. Tighten:
Pinch bolt (handle crown) 1
Pinch bolt (under bracket) 2
CAUTION:
Tighten the under bracket to specified
torque. If torqued too much, it may cause
the front fork to malfunction.
Front fork top end (standard) a:
Zero mm (Zero in)
T R..30 Nm (3.0 m · kg, 22 ft · lb)
T R..23 Nm (2.3 m · kg, 17 ft · lb)
T R..20 Nm (2.0 m · kg, 14 ft · lb)

5 - 49
CHASSTEERING
9. Install:
Steering shaft cap 1
10. After tightening the nut, check the steer-
ing for smooth movement. If not, adjust
the steering by loosening the ring nut little
by little.
11. Adjust:
Front fork top end a
Front fork top end (standard) a:
Zero mm (Zero in)
12. Tighten:
Pinch bolt (handle crown) 1
Pinch bolt (under bracket) 2
CAUTION:
Tighten the under bracket to specified
torque. If torqued too much, it may cause
the front fork to malfunction.
T R..23 Nm (2.3 m · kg, 17 ft · lb)
T R..20 Nm (2.0 m · kg, 14 ft · lb)

7 - 22
TUNSETTING
EC72H002
Suspension setting
Front fork
NOTE:
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
gapMedium
gapSmall
gap
Stiff over entire range

Compression damping
Oil level (oil amount)
SpringTurn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Decrease oil level by about 5 ~ 10 mm (0.2 ~ 0.4 in).
Replace with soft spring.
Unsmooth movement
over entire range

Outer tube
Inner tube
Under bracket tightening
torqueCheck for any bends, dents, and other noticeable
scars, etc. If any, replace affected parts.
Retighten to specified torque.
Poor initial
movement

Rebound damping
Oil sealTurn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Apply grease in oil seal wall.
Soft over entire range,
bottoming out

Compression damping
Oil level (oil amount)
SpringTurn adjuster clockwise (about 2 clicks) to increase
damping.
Increase oil level by about 5 ~ 10 mm (0.2 ~ 0.4 in).
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 movement
Compression dampingTurn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Low front, tending to
lower front posture

Compression damping
Rebound damping
Balance with rear end
Oil level (oil amount)Turn adjuster clockwise (about 2 clicks) to increase
damping.
Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Set sunken length for 95 ~ 100 mm (3.7 ~ 3.9 in) when
one passenger is astride seat (lower rear posture).
Increase oil level by about 5 mm (0.2 in).
“Obtrusive” front, tend-
ing to upper front pos-
ture

Compression damping
Balance with rear end
Spring
Oil lever (oil amount)Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Set sunken length for 90 ~ 95 mm (3.5 ~ 3.7 in) when
one passenger is astride seat (upper rear posture).
Replace with soft spring.
Decrease oil level by about 5 ~ 10 mm (0.2 ~ 0.4 in).