2002 YAMAHA YZ426F engine

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 brake reservoir tank and frame M6 × 1.0 1 10 1.0 7.2
Rear brake hose union bolt (caliper) M10 × 1.25 1 30 3.0 22
Rear brake hose union bolt (master cylinder) M10 × 1.25 1 30 3.0 22
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
Engine mounting:
Engine bracket and frame M8 × 1.25 7 34 3.4 24
Engine and frame (front) M10 × 1.25 1 69 6.9 50
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
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 M8 × 1.25 3 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 4 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 M6 × 1.0 4 7 0.7 5.1
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
Hose guide
2
Brake hose
3
Fuel tank breather hose
4
Oil tank breather hose
5
Clamp
6
Sub wire harness
7
TPS (throttle position
sensor) lead
8
Neutral switch lead
9
Oil hose
0
Hose holder
A
CDI magneto lead
B
Clutch cable
C
Cylinder head breather hose
D
Carburetor breather hose
E
Overflow hose
Å
Pass the clutch cable through
the cable guide.
ı
Pass the fuel tank breather hose
between the handlebar and ten-
sion bar, then insert its end into
the hole of the number plate.
Ç
Pass the decompression cable
under the oil tank breather pipe.
Î
Fasten the CDI magneto lead
and neutral switch lead to the
frame with a plastic locking tie
and cut off the tie end.
‰
Fasten the sub wire harness to
the frame at the white tape for
the sub wire harness with a
plastic locking tie and cut off the
tie end.
Ï
Pass the cylinder head breather
hose along the right side of the
oil tank breather hose.
Ì
Fasten the sub wire harness to
the frame with a plastic locking
tie ends at the lower left of the
frame and cut off the tie end. For
fastening, pass the plastic lock-
ing tie through the upper holes
in the engine brackets.
Ó
Pass the sub wire harness
between the engine brackets.

2 - 22
SPEC

CABLE ROUTING DIAGRAM
È
Fasten the TPS lead (in the
sub wire harness) under the
frame so that it does not con-
tact the carburetor.
Ô
Make sure that the TPS lead
coupler does not go outside the
chassis.

Fasten the TPS lead under the
coupler to the frame with a
plastic locking tie.
Ò
Pass the carburetor breather
hose and overflow hose
between the connecting rod
and cross tube (frame).
˜Fasten the neutral switch lead
and oil hose together with a
plastic locking tie and cut off
the tie end.ˆFasten the cylinder head
breather hose with the hose
holder.
ØFasten the neutral switch lead
to the frame with a plastic band
ends toward the rear of the
frame.
∏Fasten the cylinder head
breather hose with the hose
holder.
ŒPass the clutch cable through
the cable guide.
ÂFasten the neutral switch lead
and CDI magneto lead together
with a plastic band.
ÍPass the clutch cable on the
inside the cylinder head
breather hose.ÊPass the cylinder head
breather hose along the inner
side of the radiator pipe.
ËPass the radiator breather
hose from the right side of the
frame to the left side, over radi-
ator pipe 1, along the inner side
of radiator hose 4 and the radi-
ator, and between the lower
engine bracket, crankcase, oil
hose and the frame.
◊Pass the clutch cable between
the frame and radiator and
over the lower boss on the radi-
ator.

2 - 24
SPECCABLE ROUTING DIAGRAM
1Clamp
2Ignition coil
3High tension cord
4CDI unit
5CDI unit band
6“ENGINE STOP” button
lead
7Throttle cable (pull)
8Throttle cable (return)
9Radiator (left)
0Radiator breather hose
ARadiator (right)
BCDI unit stay (frame)ÅFasten the ignition coil lead to the
frame with a plastic band.
ıFasten the ignition coil and ground
lead to the frame with the bolt.
ÇPass the ignition coil lead (in the
sub wire harness) so that it does
not contact the carburetor and
rear shock absorber and connect
it with the lead from the ignition
coil on the inside of the frame.
ÎPass the throttle cables over the
high tension cord.
‰Pass the throttle cables along the
outer side of the CDI unit leads.
ÏFasten the CDI unit leads and
“ENGINE STOP” button lead to the
frame at the protector of the CDI
unit leads with a plastic locking tie.
ÌPass the radiator breather hose
on the outside the CDI unit lead
and “ENGINE STOP” button lead.ÓPass the CDI unit lead and
“ENGINE STOP” button lead over
the top radiator mounting boss.
ÈPass the throttle cables and
“ENGINE STOP” button lead
through the cable guide.
ÔCross the pull and return throttle
cables before the radiator.
Pass the throttle cables, “ENGINE
STOP” button lead and CDI unit
lead through the cable guide.
ÒPass the throttle cables between
the top radiator mounting boss and
middle radiator mounting boss.
˜Pass the radiator breather hose
between the frame and the radia-
tor without pinching it.
ˆPass the radiator breather hose
behind the decompression cable.
ØInsert the CDI unit band over the
CDI unit stay (frame) as far as
possible.

SPEC
2 - 24
CHEMINEMENT DES CABLES
KABELFÜHRUNG
1Kabelbinder
2Zündspule
3Hochspannungskabel
4CDI-Zündbox
5CDI-Zündbox-Befestigungsband
6Motorstoppschalter-Kabel
7Drosselklappenzug (Ziehen)
8Drosselklappenzug (Rückführen)
9Kühler (links)
0Kühler-Entlüftungsschlauch
AKühler (rechts)
BCDI-Zündbox-Halterung
ÅDas Zündspulen-Kabel mit mehrf. verwendb.
Kabelbinder am Rahmen befestigen.
ıDie Zündspulen- und Massekabel mit am Rah-
men festschrauben.
ÇDas Zündspulenkabel (im Nebenkabelbaum) so
verlegen, daß es den Vergaser und das Feder-
bein nicht berührt, und anschließend mit dem
Zündspulenkabal an der Rahmeninnenseite ver-
binden.
ÎDie Gasseilzüge über das Hochspannungskabel
führen.
‰Die Gasseilzüge vor dem CDI-Zündbox-Leitun-
gen führen.
ÏDie Kabel der CDI-Einheit und das Motorstopp-
schalterkabel zum Rahmen am Protektor der
CDI-Einheit-Kabel mit einem Einweg-Kabelbin-
der befestigen.
ÌDen Kühler-Lüftungsschlauch außen am CDI-
Einheit-Kabel und am Motorstoppschalterkabel
verlegen.
ÓDas CDI-Einheit-Kabel und am Motorstopp-
schalterkabel über die obere Kühlerhaltebüchse
führen.
ÈDie Gaszüge und das Motorstoppschalterkabel
durch die Seilzugführung führen.
ÔDen Zug kreuzen und die Drosselklappenzüge
vor dem Kühler zurückverlegen.
Die Gaszüge, das Motorstoppschalterkabel und
das CDI-Einheit-Kabel durch die Seilzugführung
führen.
ÒDie Gaszüge zwischen der oberen Kühlerhalte-
büchse und der mittleren Kühlerhaltebüchse
verlegen.
˜Den Kühler-Belüftungsschlauch zwischen Rah-
men und Kühler führen, ohne ihn einzuklemmen.
ˆDen Kühlerentlüftungsschlauch hinter dem
Dekompressionszug entlangführen.
ØDas CDI-Zündbox-Befestigungsband so weit wie
möglich über der CDI-Zündbox-Halterung füh-
ren. 1Bride
2Bobine d’allumage
3Cordon de haute tension
4Bloc CDI
5Attache de bloc CDI
6Fil de bouton d’arrêt du moteur “ENGINE STOP”
7Câble d’accélérateur (tirage)
8Câble d’accélérateur (rappel)
9Radiateur (gauche)
0Reniflard de radiateur
ARadiateur (droit)
BSupport du bloc CDI (cadre)
ÅAttacher le fil de bobine d’allumage au cadre à l’aide
d’une attache en plastique.
ıAttacher le fil de bobine d’allumage et le fil de la
masse au cadre à l’aide d’un boulon.
ÇFaire passer le fil de bobine d’allumage (dans le fais-
ceau de fils secondaires) de sorte qu’il ne touche pas
le carburateur et l’amortisseur arrière et le raccorder
au fil de la bobine d’allumage à l’intérieur du cadre.
ÎFaire passer les câbles d’accélération par-dessus le
cordon de haute tension.
‰Faire passer les câbles d’accélération par-devant les
fils du bloc CDI.
ÏAttacher les fils du bloc CDI et le fil du bouton
d’arrêt du moteur “ENGINE STOP” au cadre à la
hauteur de la protection des fils du bloc CDI avec une
attache en plastique.
ÌFaire passer le reniflard du radiateur à l’extérieur des
fils du bloc CDI et du fil du bouton d’arrêt du moteur
“ENGINE STOP”.
ÓFaire passer le fil du bloc CDI et le fil du bouton
d’arrêt du moteur “ENGINE STOP” par-dessus la
noix de montage supérieure du radiateur.
ÈFaire passer les câbles d’accélération et le fil du bou-
ton d’arrêt du moteur “ENGINE STOP” dans le
guide des câbles.
ÔEntrecroiser les câbles de tirage et de rappel de
l’accélérateur devant le radiateur.
Faire passer les câbles d’accélération, le fil du bouton
d’arrêt du moteur “ENGINE STOP” et le fil du bloc
CDI dans le guide des câbles.
ÒFaire passer les câbles d’accélération entre la noix de
montage supérieure et centrale du radiateur.
˜Faire passer le reniflard de radiateur entre le cadre et
le radiateur en évitant de le pincer.
ˆFaire passer le flexible de reniflard de radiateur der-
rière le câble de décompression.
ØInsérer l’attache du bloc CDI par-dessus le support du
bloc CDI (cadre) aussi loin que possible.

2 - 25
SPECCABLE ROUTING DIAGRAM
1Throttle cable
2Clamp
3Decompression cable
4Clutch cable
5Brake hose
6Hose guide
7“ENGINE STOP” button leadÅFasten the “ENGINE STOP” button lead to the handlebar with the
plastic band.
ıPass the brake hose in front of the number plate.

SPEC
2 - 25
CHEMINEMENT DES CABLES
KABELFÜHRUNG
1Gaszug
2Kabelbinder
3Dekompressionszug
4Kupplungszug
5Bremsschlauch
6Kabelführung
7Motorstoppschalter-Kabel
ÅDas Motorstoppschalter-Kabel mit mehrf. ver-
wendb. Kabelbinder am Lenker befestigen.
ıDen Bremsschlauch vor dem Nummernschild
führen. 1Câble d’accélération
2Bride
3Câble du décompresseur
4Câble d’embrayage
5Tuyau de frein
6Guide de flexible
7Fil de bouton d’arrêt du moteur “ENGINE STOP”
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.