warning YAMAHA YZ426F 2000 Owner's Guide

5 - 20
CHASFRONT BRAKE AND REAR BRAKE
EC5A5200
Master cylinder kit
1. Clean:
lMaster cylinder
lMaster cylinder kit
Clean them with brake fluid.
2. Install:
lMaster cylinder cup (primary) 1
lMaster cylinder cup (secondary) 2
To master cylinder piston 3.
NOTE:
Apply the brake fluid on the master cylinder
cup.
WARNING
After installing, cylinder cup should be
installed as shown direction. Wrong instal-
lation cause improper brake performance.
Front
õRear
õ
õ
3. Install:
lSpring 1
To master cylinder piston 2.
NOTE:
Install the spring at the smaller diameter side.
Front
õRear
õ

5 - 21
CHAS

FRONT BRAKE AND REAR BRAKE
4. Install:
[Front]
l
Master cylinder kit
1

l
Push rod
2

l
Plain washer
3

l
Circlip
4

l
Master cylinder boot
5

l
Locknut
6

To master cylinder
7
.
[Rear]
l
Master cylinder kit
1

l
Push rod
2

l
Circlip
3

l
Master cylinder boot
4

l
Locknut
5

To master cylinder
6
.
NOTE:

l
Apply the brake fluid on the master cylinder
kit.
l
Apply the lithium soap base grease on the tip
of the push rod.
l
When installing the circlip, use a long nose
circlip pliers.

Front
õ
Rear
EC5A5300
Front master cylinder
1. Install:
l
Master cylinder
1

l
Master cylinder bracket
2

l
Bolt (master cylinder bracket)
3

NOTE:

l
Install the bracket so that the arrow mark
a
face upward.
l
First tighten the bolts on the upper side of the
master cylinder bracket, and then tighten the
bolts on the lower side.
WARNING

Install the master cylinder so that the gaps
b
and
c
between the bolt (grip cap)
4
and
push rod
5
are equal. If you make a mis-
take in the master cylinder installation
position, the brake lever may contact the
grip cap, resulting in poor brake perfor-
mance.

õ
T R..9 Nm (0.9 m · kg, 6.5 ft · lb)

5 - 24
CHASFRONT BRAKE AND REAR BRAKE
3. Pass the brake hose through the cable
guide 1, then through the guide a on
the protector 2.
4. Install:
lCopper washer 1
lBrake hose 2
lUnion bolt 3
WARNING
Always use new copper washers.
ACHTUNG:CAUTION:
Install the brake hose so that its pipe por-
tion a directs as show and lightly touches
the projection b on the master cylinder.
New
T R..30 Nm (3.0 m · kg, 22 ft · lb)
EC5A5500
Rear brake hose
1. Install:
lCopper washer 1
lBrake hose 2
lCopper washer 3
lUnion bolt 4
WARNING
Always use new copper washers.
ACHTUNG:CAUTION:
When installing the brake hose, first align
the tooth a on the copper washer 1 with
the projection b on the master cylinder.
Then, align the pipe portion on the end of
the brake hose with the tooth c on the cop-
per washer 1 and tighten the union bolt.
New
New
T R..30 Nm (3.0 m · kg, 22 ft · lb)

5 - 25
CHASFRONT BRAKE AND REAR BRAKE
2. Install:
lBrake hose holder 1
lScrew (brake hose holder) 2
ACHTUNG:CAUTION:
After installing the brake hose holders,
make sure the brake hose does not contact
the spring (rear shock absorber). If it does,
correct its twist.
T R..4 Nm (0.4 m · kg, 2.9 ft · lb)
EC5A5600
Brake fluid
1. Fill:
lBrake fluid
Until the fluid level reaches “LOWER”
level line a.
WARNING
lUse only the designated quality brake
fluid:
otherwise, the rubber seals may deterio-
rate, causing leakage and poor brake per-
formance.
lRefill with the same type of brake fluid;
mixing fluids may result in a harmful chem-
ical reaction and lead to poor performance.
lBe careful that water does not enter the
master cylinder when refilling. Water will
significantly lower the boiling point of the
fluid and may result in vapor lock.
ACHTUNG:CAUTION:
Brake fluid may erode painted surfaces or
plastic parts. Always clean up spilled fluid
immediately.
Front
õRear
Recommended brake fluid:
DOT #4

õ

5 - 27
CHASFRONT FORK
EC550000
FRONT FORK
Extent of removal:1 Front fork removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removalFRONT FORK REMOVAL
Hold the machine by placing the
suitable stand under the engine.
Front wheel Refer to “FRONT WHEEL AND REAR
WHEEL” section.
Front caliper Refer to “FRONT BRAKE AND REAR
BRAKE” section.
Number plate
1 Protector 1
2 Brake hose holder 2
3 Pinch bolt (handle crown) 2 Only loosening.
4 Cap bolt 1Loosen when disassembling the front fork.
5 Pinch bolt (under bracket) 2 Only loosening.
6 Front fork 1
WARNING
Support the machine securely so there is nodanger of it falling over.
1

5 - 31
CHAS
EC554200
Base valve
1. Inspect:
lValve assembly 1
Wear/damage ® Replace.
lO-ring 2
Damage ® Replace.
EC554400
Fork spring
1. Measure:
lFork spring free length a
Out of specification ® Replace.
EC554502
Inner tube
1. Inspect:
lInner tube surface a
Score marks ® Repair or replace.
Use #1,000 grit wet sandpaper.
Damaged oil lock piece ® Replace.
lInner tube bends
Out of specification ® Replace.
Use the dial gauge 1.
NOTE:
The bending value is shown by one half of the
dial gauge reading.
WARNING
Do not attempt to straighten a bent inner
tube as this may dangerously weaken the
tube.
EC554600
Outer tube
1. Inspect:
lOuter tube 1
Score marks/wear/damage ® Replace.
Fork spring free length
Standard Limit
460 mm
(18.1 in)455 mm
(17.9 in)
Inner tube bending limit:
0.2 mm (0.008 in)
FRONT FORK

5 - 36
CHASFRONT FORK
19. Wait ten minutes until the air bubbles
have been removed from the front fork,
and the oil has dispense evenly in system
before setting recommended oil level.
NOTE:
Fill with the fork oil up to the top end of the
outer tube, or the fork oil will not spread over to
every part of the front forks, thus making it
impossible to obtain the correct level.
Be sure to fill with the fork oil up to the top of
the outer tube and bleed the front forks.
20. Measure:
lOil level (left and right) a
Out of specification ® Adjust.
NOTE:
Be sure to install the spring guide 2 when
checking the oil level.
WARNING
Never fail to make the oil level adjustment
between the maximum and minimum level
and always adjust each front fork to the
same setting. Uneven adjustment can
cause poor handling and loss of stability.
Standard oil level:
130 mm (5.12 in)
Extent of adjustment:
80 ~ 150 mm (3.15 ~ 5.91 in)
From top of outer tube with
inner tube and damper rod 1
fully compressed without
spring.

5 - 41
CHAS

EC5B3000
REMOVAL POINTS
EC5B3100
Master cylinder
1. Remove:
l
Master cylinder bracket
1

l
Master cylinder
2

ACHTUNG:CAUTION:

l
Do not let the master cylinder hang on the
brake hose.
l
Keep the master cylinder cap side hori-
zontal to prevent air from coming in.
EC5B3200
Grip
1. Remove:
l
Grip
1

NOTE:

Blow in air between the handlebar or tube
guide and the grip. Then remove the grip
which has become loose.
EC5B4000
INSPECTION
EC5B4100
Handlebar
1. Inspect:
l
Handlebar
1

Bends/cracks/damage
®
Replace.
WARNING

Do not attempt to straighten a bent handle-
bar as this may dangerously weaken the
handlebar.
EC5B5000
ASSEMBLY AND INSTALLATION
1. Install:
l
Handlebar
1

l
Handlebar holder
2

l
Bolt (handlebar holder)
3

NOTE:

l
The upper handlebar holder should be
installed with the punched mark
a
forward.
l
First tighten the bolts on the front side of the
handlebar holder, and then tighten the bolts
on the rear side.
T R..23 Nm (2.3 m · kg, 17 ft · lb)

HANDLEBAR

5 - 43
CHAS

HANDLEBAR
5. Install:
l
Throttle cable cap
1

l
Screw (throttle cable cap)
2

l
Cover (throttle cable cap)
3

WARNING

After tightening the screws, check that the
throttle grip
4
moves smoothly. If it does
not, retighten the bolts for adjustment.
T R..4 Nm (0.4 m · kg, 2.9 ft · lb)

6. Install:
l
Master cylinder
1
lMaster cylinder bracket 2
lBolt (master cylinder bracket) 3
NOTE:
lInstall the bracket so that the arrow mark a
faces upward.
lFirst tighten the bolt on the upper side of the
master cylinder bracket, and then tighten the
bolt on the lower side.
T R..9 Nm (0.9 m · kg, 6.5 ft · lb)
7. Install:
l“ENGINE STOP” button 1
lClutch lever holder 2
lBolt (clutch lever holder) 3
lDecompression lever holder 4
lScrew (decompression lever holder) 5
lClamp 6
T R..4 Nm (0.4 m · kg, 2.9 ft · lb)
T R..4 Nm (0.4 m · kg, 2.9 ft · lb)

5 - 45
CHAS
EC560000
STEERING
Extent of removal:1 Under bracket removal2 Bearing removal
Extent of removal Order Part name Q’ty Remarks
STEERING REMOVAL
Refer to “HANDLEBAR” section. Preparation for removal Hold the machine by placing the
suitable stand under the engine.
Number plate
Handlebar
Cable guide
Front fender
1 Steering shaft nut 1
2 Front fork 2 Refer to “FRONT FORK” section.
3 Handle crown 1
4 Ring nut 1 Use special tool.
Refer to “REMOVAL POINTS”.
5 Under bracket 1
6 Ball race cover 1
7 Bearing (upper) 1
8 Bearing (lower) 1 Refer to “REMOVAL POINTS”.
9 Ball race 2 Refer to “REMOVAL POINTS”.
WARNING
Support the machine securely so there is nodanger of it falling over.
2
1
STEERING