2001 YAMAHA YZ426F torque

SPEC
2 - 18
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
2Pressure
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
GENERAL TORQUE SPECIFICATIONS/
DEFINITION OF UNITS

3 - 43
INSP
ADJ
STEERING HEAD INSPECTION AND ADJUSTMENT
lTighten the ring nut 3 using ring nut
wrench 4.
NOTE:
Set the torque wrench to the ring nut wrench
so that they form a right angle.
Ring nut wrench:
YU-33975/90890-01403
T R..
Ring nut (initial tightening):
38 Nm (3.8 m • kg, 27 ft • lb)
lLoosen the ring nut one turn.
lRetighten the ring nut using the ring nut
wrench.
WARNING
Avoid over-tightening.
T R..
Ring nut (final tightening):
7 Nm (0.7 m • kg, 5.1 ft • lb)
lCheck the steering shaft by turning it lock
to lock. If there is any binding, remove the
steering shaft assembly and inspect the
steering bearings.
lInstall the handle crown 5, steering shaft
nut 6, handlebar 7, handlebar holder 8
and number plate 9.
NOTE:
lThe upper handlebar holder should be
installed with the punched mark a for-
ward.
lInsert the end of fuel breather hose 0 into
the hole of the number plate.
CAUTION:
First tighten the bolts on the front side of
the handlebar holder, and then tighten
the bolts on the rear side.
T R..
Steering shaft nut:
145 Nm (14.5 m • kg, 105 ft • lb)
Handlebar upper holder:
28 Nm (2.8 m • kg, 20 ft • lb)
Pinch bolt (handle crown):
23 Nm (2.3 m • kg, 17 ft • lb)
Number plate:
7 Nm (0.7 m • kg, 5.1 ft • lb)

4 - 13
ENG
CARBURATEUR
VERGASER
Choke-Schieber
1. Kontrollieren:
lKaltstarter-Tauchkolben 1
lHeißstarter-Tauchkolben (rot) 2
Verschleiß/Beschädigung ® Erneuern.
Beschleunigungspumpe
1. Kontrollieren:
lMembran (Beschleunigungspumpe) 1
lFeder 2
lDeckel 3
lO-Ring 4
lDruckstange 5
Rißbildung (Membran)/Beschädigung ®
Erneuern.
Schmutz ® Säubern.
2. Inspizieren:
lDrosselwelle 1
lFeder 2
lHebel 1 3
lFeder 1 4
lHebel 2 5
lFeder 2 6
Schmutz ® Säubem
ZUSAMMENBAU UND MONTAGE
Vergaser
1. Montieren:
lHeißstarter-Tauchkolben (rot) 1
lKaltstarter-Tauchkolben 2
2. Montieren:
lHauptluftdüse 1
lLeerlaufluftdüse 2
lAnsaugstutzen 3 T R..5 Nm (0,5 m · kg)
Plongeur de starter
1. Contrôler:
lPlongeur de démarrage à froid 1
lPlongeur de démarrage à chaud (rouge) 2
Usure/endommagement ® Remplacer.
Pompe d’accélérateur
1. Contrôler:
lDiaphragme (pompe d’accélérateur) 1
lRessort 2
lCouvercle 3
lJoint torque 4
lTige de commande 5
Déchirure (diaphragme)/endommagement
® Remplacer.
Sale ® Nettoyer.
2. Inspecter:
lAxe de papillon 1
lRessort 2
lLevier 1 3
lRessort 1 4
lLevier 2 5
lRessort 2 6
Sale ® Nettoyer
ASSEMBLAGE ET MONTAGE
Carburateur
1. Monter:
lPlongeur de démarrage à chaud (rouge) 1
lPlongeur de démarrage à froid 2
2. Monter:
lGicleur d’air principal 1
lGicleur d’air de ralenti 2
lRaccord d’admission 3
T R..5 Nm (0,5 m · kg, 3,6 ft · lb)

4 - 25
ENGCAMSHAFTS
2. Install:
lTiming chain tensioner
3. Turn:
lCrankshaft
Counterclockwise several turns
4. Check:
lRotor “I” mark
Align with the crankcase stationary
pointer.
lCamshaft match marks
Align with the cylinder head surface.
Out of alignment ® Adjust.
lInstall the dowel pins, clips and camshaft
caps 4.
T R..
Bolt (camshaft cap):
10 Nm (1.0 m • kg, 7.2 ft • lb)
NOTE:
.Tighten the bolts (camshaft cap) 5 in a
crisscross pattern.
CAUTION:
The bolts (camshaft cap) must be tight-
ened evenly or damage to the cylinder
head, camshaft caps and camshaft will
result.
Installation steps:
lWhile pressing the tensioner rod lightly
with fingers, use a thin screwdriver and
wind the tensioner rod up fully clockwise.
lWith 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)
lRelease 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 - 38
CHAS

FRONT FORK
26. Tighten:
l
Cap bolt (locknut)
1

NOTE:

l
While compressing the fork spring, set the
thin type spanners
2
between the spacer
3
and spring guide
4
.
l
Hold the locknut
5
and tighten the cap bolt
with specified torque.
27. Install:
l
Cap bolt
1

To outer tube.
NOTE:

Temporarily tighten the cap bolt.
T R..29 Nm (2.9 m · kg, 21 ft · lb)

28. Install:
l
Protector guide
1

Installation
1. Install:
l
Front fork
1

NOTE:

l
Temporarily tighten the pinch bolts (under
bracket).
l
Do not tighten the pinch bolts (handle crown)
yet.
2. Tighten:
l
Cap bolt
1

3. Adjust:
l
Front fork top end
a
Front fork top end (standard) a:
Zero mm (Zero in)
T R..30 Nm (3.0 m · kg, 22 ft · lb)

5 - 39
CHAS

FRONT FORK
4. Tighten:
l
Pinch bolt (handle crown)
1

l
Pinch bolt (under bracket)
2

ACHTUNG:CAUTION:

Tighten the under bracket to specified
torque. If torqued too much, it may cause
the front fork to malfunction.
5. Install:
l
Brake hose holder
1

l
Caliper
2

l
Bolt (caliper)
3

NOTE:

Fit the brake hose holder cut
a
over the pro-
jection
b
on the front fork and clamp the brake
hose.
6. Install:
l
Brake hose holder
1

l
Bolt (brake hose holder)
2

l
Protector
3

l
Bolt (protector)
4

NOTE:

When installing the brake hose holder, pass
the brake hose
5
in front of the axle boss
a
,
then fit it into the hose groove
b
so that the
brake hose does not contact the nut (wheel
axle).
T R..23 Nm (2.3 m · kg, 17 ft · lb)
T R..20 Nm (2.0 m · kg, 14 ft · lb)
T R..23 Nm (2.3 m · kg, 17 ft · lb)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)

7. Adjust:
l
Rebound damping force
NOTE:

Turn in the damping adjuster
1
finger-tight
and then turn out to the originally set position.

5 - 49
CHASSTEERING
9. After tightening the nut, check the steer-
ing for smooth movement. If not, adjust
the steering by loosening the ring nut little
by little.
10. Adjust:
lFront fork top end a
Front fork top end (standard) a:
Zero mm (Zero in)
11. Tighten:
lPinch bolt (handle crown) 1
lPinch bolt (under bracket) 2
ACHTUNG: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 - 20
TUN

SETTING
EC72H002
Suspension setting
l
Front fork
NOTE:

l
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.
l
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
gap
Medium
gap
Small
gap
Stiff over entire range
CCC
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
CCCC
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
C
Rebound damping
Oil sealTurn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Apply grease in oil seal wall.
Soft over entire range,
bottoming out
CC
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
C
Oil level (oil amount) Decrease oil level by about 5 mm (0.2 in).
Soft toward stroke end,
bottoming out
C
Oil level (oil amount) Increase oil level by about 5 mm (0.2 in).
Stiff initial movement
CCCC
Compression dampingTurn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Low front, tending to
lower front posture
CC
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
CC
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).