engine YAMAHA YZ450F 2003 Owner's Guide

SPEC

2 - 4
MAINTENANCE SPECIFICATIONS
MAINTENANCE SPECIFICATIONS
ENGINE
Item Standard Limit
Cylinder head:
Warp limit ---- 0.05 mm
(0.002 in)
Cylinder:
Bore size 95.00 ~ 95.01 mm
(3.7402 ~ 3.7406 in)----
Out of round limit ---- 0.05 mm
(0.002 in)
Camshaft:
Drive method Chain drive (Left) ----
Camshaft cap inside diameter 22.000 ~ 22.021 mm
(0.8661 ~ 0.8670 in)----
Camshaft journal diameter 21.967 ~ 21.980 mm
(0.8648 ~ 0.8654 in)----
Shaft-to-cap clearance 0.020 ~ 0.054 mm
(0.0008 ~ 0.0021 in)0.08 mm
(0.003 in)
Cam dimensions
Intake“A”31.200 ~ 31.300 mm
(1.2283 ~ 1.2323 in)31.100 mm
(1.2244 in)
“B”22.550 ~ 22.650 mm
(0.8878 ~ 0.8917 in)22.450 mm
(0.8839 in)
Exhaust“A”30.950 ~ 31.050 mm
(1.2185 ~ 1.2224 in)30.850 mm
(1.2146 in)
“B”22.494 ~ 22.594 mm
(0.8856 ~ 0.8895 in)22.394 mm
(0.8817 in)
Camshaft runout limit ---- 0.03 mm
(0.0012 in)
A
B

SPEC

2 - 8
MAINTENANCE SPECIFICATIONS
Clutch:
Friction plate thickness 2.92 ~ 3.08 mm
(0.115 ~ 0.121 in)2.8 mm
(0.110 in)
Quantity 9 ----
Clutch plate thickness 1.1 ~ 1.3 mm (0.043 ~ 0.051 in) ----
Quantity 8 ----
Warp limit ---- 0.1 mm
(0.004 in)
Clutch spring free length 50 mm (1.97 in) 49 mm
(1.93 in)
Quantity 6 ----
Clutch housing thrust clearance 0.10 ~ 0.35 mm
(0.0039 ~ 0.0138 in)----
Clutch housing radial clearance 0.010 ~ 0.044 mm
(0.0004 ~ 0.0017 in)----
Clutch release method Inner push, cam push ----
Shifter:
Shifter type Cam drum and guide bar ----
Guide bar bending limit ---- 0.05 mm
(0.002 in)
Kick starter:
Type Ratchet type ----
Carburetor:
I. D. mark 5TA1 00 ----
Main jet (M.J) #165 ----
Main air jet (M.A.J) #200 ----
Jet needle - clip position (J.N) NCVQ-4 ----
Cutaway (C.A) 1.5 ----
Pilot jet (P.J) #42 ----
Pilot air jet (P.A.J) #100 ----
Pilot outlet (P.O)ø0.9 ----
Pilot screw (example) (P.S) 2 ----
Bypass (B.P)ø1.0 ----
Valve seat size (V.S)ø3.8 ----
Starter jet (G.S) #72 ----
Float height (F.H) 8 mm (0.31 in) ----
Engine idle speed 1,900 ~ 2,100 r/min ----
Intake vacuum28.0 ~ 33.3 kPa (210 ~ 250 mmHg,
8.27 ~ 9.84 inHg)----
Hot starter lever free play 3 ~ 6 mm (0.12 ~ 0.24 in)---- Item Standard Limit

SPEC

2 - 11
MAINTENANCE SPECIFICATIONS
Part to be tightened Thread size Q’tyTightening torque
Nm m·kg ft·lb
Spark plug M10S
×
1.0 1 13 1.3 9.4
Camshaft cap M6
×
1.0 10 10 1.0 7.2
Cylinder head blind plug screw M12
×
1.0 1 37 3.7 27
Cylinder head (stud bolt) M6
×
1.0 2 7 0.7 5.1
M8
×
1.25 1 15 1.5 11
(bolt) M10
×
1.25 4 Refer to NOTE.*
1

(nut) M6
×
1.0 2 10 1.0 7.2
Cylinder head cover M6
×
1.0 2 10 1.0 7.2
Cylinder M6
×
1.0 1 10 1.0 7.2
Timing chain tensioner M6
×
1.0 2 10 1.0 7.2
Tensioner cap bolt M6
×
1.0 1 7 0.7 5.1
Timing chain guide (rear) M6
×
1.0 2 10 1.0 7.2
Exhaust pipe (nut) M8
×
1.25 1 13 1.3 9.4
(bolt) M8
×
1.25 1 24 2.4 17
Silencer M8
×
1.25 2 35 3.5 25
Silencer clamp M8
×
1.25 1 20 2.0 14
Exhaust pipe protector M6
×
1.0 3 10 1.0 7.2
Clamp (cylinder head side) M5
×
0.8 1 3 0.3 2.2
Clamp (carburetor side) M4
×
0.7 1 3 0.3 2.2
Air filter case M6
×
1.0 2 8 0.8 5.8
Air filter joint clamp M6
×
1.0 1 3 0.3 2.2
Air filter joint and air filter case M5
×
0.8 1 4 0.4 2.9
Throttle cable cover M5
×
0.8 2 4 0.4 2.9
Hot starter plunger M12
×
1.0 1 2 0.2 1.4
Air filter element M6
×
1.0 1 2 0.2 1.4
Radiator panel (upper) M6
×
1.0 2 10 1.0 7.2
Radiator M6
×
1.0 6 10 1.0 7.2
Radiator hose clamp M6
×
1.0 8 2 0.2 1.4
Radiator pipe 1, 2 M10
×
1.0 2 10 1.0 7.2
Impeller M8
×
1.25 1 14 1.4 10
Water pump housing cover M6
×
1.0 3 10 1.0 7.2
Coolant drain bolt M6
×
1.0 1 10 1.0 7.2
Oil pump cover M4
×
0.7 1 3 0.3 2.2
Oil pump M6
×
1.0 3 10 1.0 7.2
Engine oil drain bolt (oil filter) M6
×
1.0 1 10 1.0 7.2
Oil filter cover M6
×
1.0 2 10 1.0 7.2
Oil delivery pipe 1 M10
×
1.25 1 20 2.0 14
M8
×
1.25 2 18 1.8 13
Oil delivery pipe 2 M6
×
1.0 1 10 1.0 7.2
Oil hose M6
×
1.0 2 10 1.0 7.2
Oil check bolt M6
×
1.0 1 10 1.0 7.2
Oil hose clamp–2 2 0.2 1.4
Clutch cover M6 × 1.0 7 10 1.0 7.2

SPEC
2 - 16
MAINTENANCE SPECIFICATIONS
NOTE:
- marked portion shall be checked for torque tightening after break-in or before each race.Part to be tightened Thread size Q’tyTightening torque
Nm m·kg ft·lb
Rear wheel axle and nut M20 × 1.5 1 125 12.5 90
Driven sprocket and wheel hub M8 × 1.25 6 42 4.2 30
Nipple (spoke)–72 3 0.3 2.2
Disc cover and rear brake caliper M6 × 1.0 2 7 0.7 5.1
Protector and rear brake caliper M6 × 1.0 2 7 0.7 5.1
Chain puller adjust bolt and locknut M8 × 1.25 2 16 1.6 11
Engine mounting:
Engine upper bracket and frame M10 × 1.25 2 55 5.5 40
Engine lower bracket and frame M8 × 1.25 4 34 3.4 24
Engine and frame (front) M10 × 1.25 1 65 6.5 47
Engine and frame (upper) M10 × 1.25 1 55 5.5 40
Engine and frame (lower) M10 × 1.25 1 69 6.9 50
Engine guard (lower) M8 × 1.25 1 23 2.3 17
Engine skid plate mounting M6 × 1.0 6 10 1.0 7.2
CDI unit bracket mounting M6 × 1.0 1 10 1.0 7.2
Pivot shaft and nut M16 × 1.5 1 85 8.5 61
Relay arm and swingarm M14 × 1.5 1 80 8.0 58
Relay arm and connecting rod M14 × 1.5 1 80 8.0 58
Connecting rod and frame M14 × 1.5 1 80 8.0 58
Rear shock absorber and frame M10 × 1.25 1 56 5.6 40
Rear shock absorber and relay arm M10 × 1.25 1 53 5.3 38
Rear frame and frame (upper) M8 × 1.25 1 32 3.2 23
Rear frame and frame (lower) M8 × 1.25 2 29 2.9 21
Swingarm and brake hose holder M5 × 0.8 4 1 0.1 0.7
Swingarm and patch M4 × 0.7 4 2 0.2 1.4
Drive chain tensioner mounting (upper) M8 × 1.25 1 19 1.9 13
Drive chain tensioner mounting (lower) M8 × 1.25 1 20 2.0 14
Chain support and swingarm M6 × 1.0 3 7 0.7 5.1
Seal guard and swingarm M5 × 0.8 4 6 0.6 4.3
Fuel tank mounting M6 × 1.0 2 10 1.0 7.2
Fuel tank and fuel cock M6 × 1.0 2 7 0.7 5.1
Fuel tank and seat set bracket M6 × 1.0 1 7 0.7 5.1
Fuel tank and hooking screw (fitting band) M6 × 1.0 1 7 0.7 5.1
Fuel tank and fuel tank bracket M6 × 1.0 4 7 0.7 5.1
Seat mounting M8 × 1.25 2 23 2.3 17
Side cover mounting M6 × 1.0 2 7 0.7 5.1
Air scoop and fuel tank M6 × 1.0 6 4 0.4 2.9
Air scoop and radiator panel (lower) M6 × 1.0 2 4 0.4 2.9
Front fender mounting M6 × 1.0 4 7 0.7 5.1
Rear fender mounting (front) M6 × 1.0 2 7 0.7 5.1
Rear fender mounting (rear) M6 × 1.0 2 10 1.0 7.2
Number plate M6 × 1.0 1 7 0.7 5.1

2 - 18
SPEC

GENERAL TORQUE SPECIFICATIONS/
DEFINITION OF UNITS
EC220001
GENERAL TORQUE SPECIFICATIONS
This chart specifies torque for standard fasten-
ers with standard I.S.O. pitch threads. Torque
specifications for special components or
assemblies are included in the applicable sec-
tions of this book. To avoid warpage, tighten
multi-fastener assemblies in a crisscross fash-
ion, in progressive stages, until full torque is
reached. Unless otherwise specified, torque
specifications call for clean, dry threads. Com-
ponents should be at room temperature.
A: Distance between flats
B: Outside thread diameter
EC230000
DEFINITION OF UNITS
A
(Nut)B
(Bolt)TORQUE
SPECIFICATION
Nm m•kg ft•lb
10 mm
12 mm
14 mm
17 mm
19 mm
22 mm6 mm
8 mm
10 mm
12 mm
14 mm
16 mm6
15
30
55
85
1300.6
1.5
3.0
5.5
8.5
134.3
11
22
40
61
94
Unit Read Definition Measure
mm
cmmillimeter
centimeter10
-3

meter
10
-2

meterLength
Length
kg kilogram 10
3

gram Weight
N Newton 1 kg
×
m/sec
2

Force
Nm
m • kgNewton meter
Meter kilogramN
×
m
m
×
kgTorque
Torque
Pa Pascal N/m
2

Pressure
N/mm Newton per millimeter N/mm Spring rate
L
cm
3

Liter
Cubic centimeter—
—Volume or capacity
Volume or capacity
r/min Revolution per minute—Engine speed

2 - 21
SPEC

CABLE ROUTING DIAGRAM
EC240000
CABLE ROUTING DIAGRAM
1
Fuel tank breather hose
2
Hot starter cable
3
Radiator hose 4
4
Cylinder head breather hose
5
Radiator hose 1
6
Oil tank breather hose
7
Hose guide
8
Brake hose
9
“ENGINE STOP” button lead
0
Clamp
A
Sub wire harness
B
TPS (throttle position sen-
sor) lead
C
Neutral switch lead
D
Oil hose
E
Radiator breather hose
F
CDI magneto lead
G
Carburetor breather hose
H
Overflow hose
Å
Pass the fuel tank breather hose
between the handlebar and ten-
sion bar, then insert its end into
the hole of the number plate.
ı
Pass the hot starter cable
between the cylinder head
breather hose, oil tank breather
hose and ignition coil, then on
the outside of the left engine
bracket.
Ç
Pass the cylinder head breather
hose on the outside of the radia-
tor hose 1 and on the inside of the
radiator pipe (radiator hose 4).
Î
Fit the brake hose into the
guides on the protector.
‰
Fasten the “ENGINE STOP”
button lead and sub wire har-
ness to the frame with a plastic
locking tie and cut off the tie
end.
ÏFasten the sub wire harness
and hot starter cable to the
frame at the white tape for the
sub wire harness with a plastic
locking tie and cut off the tie
end.
ÌFasten the sub wire harness to
the frame with a plastic locking
tie and cut off the tie end.
C
9
0
A
0
0
0
0
0
B
C
D
0 0 E 0 F 0
1
2 8
7
6
5
4
3GHG9A
D
E
C
B
A
A
C
BB
Ç ÎÅ
ıØ
˜ ˆ
Ò
Ô ÈÌ Ó Ì Ï ‰ ‰
∏
*
*

SPEC

2 - 21
CHEMINEMENT DES CABLES
KABELFÜHRUNG
KABELFÜHRUNG
1
Kraftstofftank-Belüftungsschlauch
2
Heißstarterseilzug
3
Kühlerschläuche 4
4
Zylinderkopf-Entlüftungsschlauch
5
Kühlerschläuche 1
6
Öltank-Belüftungsschlauch
7
Kabelführung
8
Bremsschlauch
9
Motorstoppschalter-Kabel
0
Kabelbinder
A
Nebenkabelsatz
B
Drosselklappen-Positionssensor (TPS)
C
Leerlaufschalter-Kabel
D
Ölschlauch
E
Kühler-Entlüftungsschlauch
FCDI-Schwungradmagnetzünder-Kabel
GVergaser-Entlüftungsschlauch
HAuslaufschutzschlauch
ÅDen Kraftstofftank-Belüftungsschlauch zwischen
Lenker und Zugstrebe führen und das Ende
durch die Bohrung im Nummerschild führen.
ıDen Heißstarter-Seilzug zwischen Zylinderkopf-
Lüfterschlauch, Öltank-Lüfterschlauch und
Zündspule verlegen, und dann an der Außensei-
te des linken Motorbügels verlegen.
ÇDen Zylinderkopf-Lüfterschlauch an der Außen-
seite des Kühlerschlauchs und an der Innenseite
der Kühlerleitung verlegen (Kühlerschlauch 4).
ÎDen Bremsschlauch in die Führungen Führun-
gen am Protektor einsetzen.
‰Die Motorstoppschalterleitung und den Neben-
kabelbaum am Rahmen mit einem Plastiksperr-
band befestigen, und bas Bandende abschei-
den.
ÏDen Nebenkabelbaum und den Heißstarterseil-
zug am Rahmen am weißen Band für den Ne-
benkabelbeum mit einem Plastiksperrband befe-
stigen, und bas Bandende abscheiden.
ÌDen Nebenkabelbaum am Rahmen mit einem
Plastiksperrband befestigen und das Bandende
abschneiden.
CHEMINEMENT DES CABLES
1Reniflard de réservoir d’essence
2Câble de démarreur à chaud
3Tuyaux du radiateur 4
4Reniflard de culasse
5Tuyaux du radiateur 1
6Reniflard de réservoir d’huile
7Guide de flexible
8Tuyau de frein
9Fil de bouton d’arrêt du moteur “ENGINE STOP”
0Bride
AFaisceau de fils secondaires
BFil de TPS (copteur du papillon d’accélération)
CFil de contacteur de point mort
DFlexible d’huile
EReniflard de radiateur
FFil de magnéto CDI
GReniflard de carburateur
HFlexible de trop-plein
ÅFaire passer le reniflard du réservoir d’essence entre
le guidon et la barre de tension, puis insérer son
extrémité dans l’orifice prévu sur la plaque de
numéro.
ıFaire passer le câble de démarreur à chaud entre le
flexible de reniflard de culasse, le flexible de reni-
flard de réservoir à huile et la bobine d’allumage,
puis sur l’extérieur du support de moteur gauche.
ÇFaire passer le flexible de reniflard de culasse sur
l’extérieur du flexible de radiateur et sur l’intérieur
du tuyau de radiateur (flexible de radiateur 4).
ÎFaire passer le tuyau de frein par le guide de la pro-
tection.
‰Attacher le fil du bouton d’arrêt du moteur et le fais-
ceau de fils secondaires au cadre avec une attache en
plastique et couper l’extrémité de l’attache.
ÏAttacher le faisceau de fils secondaires et le câble de
démarreur à chaud au cadre à la hauteur du ruban
blanc avec une attache en plastique et couper l’extré-
mité de l’attache.
ÌAttacher le faisceau de fils secondaires au cadre avec
une attache en plastique et couper l’extrémité de
l’attache.

2 - 22
SPECCABLE ROUTING DIAGRAM
ÓPass the sub wire harness
between the engine brackets.
ÈMake sure that the TPS lead
coupler does not go outside the
chassis.
ÔFasten the TPS lead to the
frame with a plastic band.
Fasten the neutral switch lead
and oil hose together with a
plastic locking tie and cut off
the tie end.
ÒFasten the neutral switch lead
to the frame with a plastic
band.
˜Fasten the neutral switch lead,
CDI magneto lead and radiator
breather hose to the frame with
a plastic band.ˆPass the neutral switch lead,
CDI magneto lead and radiator
breather hose between the
radiator and frame.
ØFasten the neutral switch lead
and CDI magneto lead to the
cable guide with a plastic lock-
ing tie and cut off the tie end.
∏Pass the carburetor breather
hoses and overflow hose so
that all there hoses do not con-
tact the rear shock absorber.*Decompression cable (sup-
plied for Europe and optional
for other destinations)
Pass the decompression cable
under the middle radiator
mounting boss and on the out-
side of the neutral switch lead,
CDI magneto lead and radiator
breather hose.
C
9
0
A
0
0
0
0
0
B
C
D
0 0 E 0 F 0
1
2 8
7
6
5
4
3GHG9A
D
E
C
B
A
A
C
BB
Ç ÎÅ
ıØ
˜ ˆ
Ò
Ô ÈÌ Ó Ì Ï ‰ ‰
∏
*
*

2 - 25
SPECCABLE ROUTING DIAGRAM
1Throttle cable
2Fuel tank breather hose
3Clamp
4Clutch cable
5Hot starter cable
6“ENGINE STOP” button lead
7Brake hose
8Hose guideÅFasten the “ENGINE STOP” but-
ton lead to the handlebar with the
plastic band.
ıPass the brake hose in front of the
number plate.
ÇPass the hot starter cable, clutch
cable and throttle cables through
the cable guide.
*Decompression cable (supplied
for Europe and optional for other
destinations)
1
23
4
5
6
7
83
6 Å
Çı
40˚±10˚
A
A
*

SPEC
2 - 25
CHEMINEMENT DES CABLES
KABELFÜHRUNG
1Gaszug
2Dekompressionszug
3Kabelbinder
4Kupplungszug
5Heißstarterseilzug
6Motorstoppschalter-Kabel
7Bremsschlauch
8Kabelführung
ÅDas Motorstoppschalter-Kabel mit mehrf. ver-
wendb. Kabelbinder am Lenker befestigen.
ıDen Bremsschlauch vor dem Nummernschild
führen.
ÇDen Heißstarter-Seilzug, den Kupplungsseilzug
und die Gasseilzüge durch die Kabelführung
verlegen.
*Dekompressionsseilzug (mitgeliefert für Europa
und optional für andere Bestimmungsgebiete) 1Câble d’accélération
2Câble du décompresseur
3Bride
4Câble d’embrayage
5Câble de démarreur à chaud
6Fil de bouton d’arrêt du moteur “ENGINE STOP”
7Tuyau de frein
8Guide de flexible
ÅFixer le fil de bouton d’arrêt du moteur “ENGINE
STOP” au guidon à l’aide d’une attache en plastique.
ıFaire passer le tuyau de frein par-devant la plaque de
numéro.
ÇFaire passer le câble du démarreur à chaud, le câble
d’embrayage et les câbles d’embrayage par le guide
de câble.*Câble de décompression (fourni pour l’Europe et en
option pour les autres pays)