2000 YAMAHA YZ426F brake

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
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 26 2.6 19
Swingarm and brake hose holder M5 ´ – 4 4 0.4 2.9
Drive chain tensioner mounting M8 ´ 1.25 2 19 1.9 13
Chain support and swingarm M6 ´ 1.0 3 7 0.7 5.1
Seal guard and swingarm M5 ´ 0.8 4 4 0.4 2.9
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
Rear fender mounting M6 ´ 1.0 4 7 0.7 5.1

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
“ENGINE STOP” button lead
7
Sub wire harness
8
TPS (throttle position sensor)
lead
9
Neutral switch lead
0
Oil hose
A
Hose holder
B
CDI magneto lead
C
Clutch cable
D
Cylinder head breather hose
E
Carburetor breather hose
F
Overflow hose

Pass the clutch cable through
the cable guide.
õ
Pass the fuel tank breather
hose between the handlebar
and tension bar, then insert its
end into the hole of the num-
ber plate.
‚
Pass the decompression cable
and “ENGINE STOP” button
lead under the frame.
ë
Pass the “ENGINE STOP” but-
ton lead along the inner side of
the decompression cable.
ä
Fasten the CDI magneto lead,
neutral switch lead and
“ENGINE STOP” button lead
to the frame with a plastic lock-
ing tie and cut off the tie end.
ì
Pass the “ENGINE STOP”
button lead along the inner
side of the oil tank breather
hose.
í
Fasten the sub wire harness
and “ENGINE STOP” button
lead to the frame with a plas-
tic locking tie and cut off the
tie end.
î
Pass the cylinder head breather
hose along the right side of the
oil tank breather hose.
é
Fasten the sub wire harness to
the frame with a plastic locking
tie and cut off the tie end.
ï
Fasten the TPS lead (in the
sub wire harness) under the
frame.

2 - 23
SPEC
ôFit the brake hose into the guide on
the protector.
çFasten the ignition coil lead (in the
sub wire harness) on the upper
inside of the frame and cut off the tie
end.
óPass the ignition coil lead (in the sub
wire harness) under the cushion
bracket (frame).
Fasten the ignition coil lead (in the
sub wire harness) to the frame with
a plastic locking tie.
Pass the carburetor breather hoses
and overflow hose so that all there
hoses do not contact the rear
shock absorber.

CABLE ROUTING DIAGRAM

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

3 - 2
INSP
ADJ

MAINTENANCE INTERVALS
SHIFT FORK, SHIFT CAM, GUIDE BAR
Inspect
c
Inspect wear
ROTOR NUT
Retighten
cc
MUFFLER
Inspect
Clean
Replace
cc
cc
* Whichever comes first
CRANK
Inspect and clean
cc
CARBURETOR
Inspect, adjust and clean
cc
When using a high-pres-
sure washer, make sure
that water does not enter
the accelerator pump.
SPARK PLUG
Inspect and clean
Replace
cc
c
DRIVE CHAIN
Lubricate, slack, alignment
Replace
cc
c
Use chain lube
Chain slack: 40~50 mm
(1.6~2.0 in)
COOLING SYSTEM
Check coolant level and leakage
Check radiator cap operation
Replace coolant
Inspect hoses
cc
cc
c
Every two years
OUTSIDE NUTS AND BOLTS
Retighten
cc
Refer to “STARTING AND
BREAK-IN” section in the
CHAPTER 1.
AIR FILTER
Clean and lubricate
Replace
cc
c
Use foam air-filter oil
OIL STRAINER (frame)
Clean
c
FRAME
Clean and inspect
cc
FUEL TANK, COCK
Clean and inspect
cc
BRAKES
Adjust lever position and pedal height
Lubricate pivot point
Check brake disc surface
Check fluid level and leakage
Retighten brake disc bolts, caliper
bolts, master cylinder bolts and union
bolts
Replace pads
Replace brake fluid
c
c
c
c
cc
c
c
c
c
c
c
Every one year
FRONT FORKS
Inspect and adjust
Replace oil
Replace oil seal
c
cc
c
c
Suspension oil “01” ItemAfter
break-inEvery
race
Every
third
(or
500 km)Every
fifth
(or
1,000 km)
As re-
quiredRemarks
3

3 - 4
INSP
ADJ

PRE-OPERATION INSPECTION AND MAINTENANCE
EC320000
PRE-OPERATION INSPECTION AND MAINTENANCE
Before riding for break-in operation, practice or a race, make sure the machine is in good operating
condition.
Before using this machine, check the following points.
EC321000
GENERAL INSPECTION AND MAINTENANCE
Item Routine Page
CoolantCheck that coolant is filled up to the radiator filler cap.
Check the cooling system for leakage.P.3-5 ~ 9
FuelCheck that a fresh gasoline is filled in the fuel tank. Check the
fuel line for leakage.P.1-12
Engine oilCheck that the oil level is correct. Check the crankcase and
frame oil line for leakage.P.3-13 ~ 17
Gear shifter and clutchCheck that gears can be shifted correctly in order and that the
clutch operates smoothly.P.3-9
Throttle grip/HousingCheck that the throttle grip operation and free play are correctly
adjusted. Lubricate the throttle grip and housing, if necessary.P.3-10 ~ 11
Brakes Check the play of front brake and effect of front and rear brake. P.3-24 ~ 30
ChainCheck chain slack and alignment. Check that the chain is lubri-
cated properly.P.3-31 ~ 33
WheelsCheck for excessive wear and tire pressure. Check for loose
spokes and have no excessive play.P.3-41 ~ 42
SteeringCheck that the handlebar can be turned smoothly and have no
excessive play.P.3-42 ~ 43
Front forks and rear shock
absorberCheck that they operate smoothly and there is no oil leakage. P.3-33 ~ 40
Cables (wires)Check that the clutch and throttle cables move smoothly. Check
that they are not caught when the handlebars are turned or
when the front forks travel up and down.—
Muffler Check that the muffler is tightly mounted and has no cracks. P.4-3
Sprocket Check that the driven sprocket tightening bolt is not loose. P.3-31
Lubrication Check for smooth operation. Lubricate if necessary. P.3-44
Bolts and nuts Check the chassis and engine for loose bolts and nuts. P.1-17
Lead connectorsCheck that the CDI magneto, CDI unit, and ignition coil are con-
nected tightly.P.1-5
SettingsIs the machine set suitably for the condition of the racing course
and weather or by taking into account the results of test runs
before racing? Are inspection and maintenance completely
done?P.7-1 ~ 21

3 - 24
INSP
ADJ
CHASSIS/BRAKE SYSTEM AIR BLEEDING
EC360000
CHASSIS
EC361012
BRAKE SYSTEM AIR BLEEDING
WARNING
Bleed the brake system if:
lThe system has been disassembled.
lA brake hose has been loosened or
removed.
lThe brake fluid is very low.
lThe brake operation is faulty.
A dangerous loss of braking performance
may occur if the brake system is not prop-
erly bleed.
1. Remove:
lMaster cylinder cap
lDiaphragm
lProtector (rear brake)
2. Bleed:
lBrake fluid
Front
õRear
Air bleeding steps:
a. Add proper brake fluid to the reservoir.
b. Install the diaphragm. Be careful not to
spill any fluid or allow the reservoir to
overflow.
c. Connect the clear plastic tube 2 tightly
to the caliper bleed screw 1.
d. Place the other end of the tube into a
container.
e. Slowly apply the brake lever or pedal
several times.
f. Pull the lever in or push down on the
pedal. Hold the lever or pedal in position.
g. Loosen the bleed screw and allow the
lever or pedal to travel towards its limit.
h. Tighten the bleed screw when the lever
or pedal limit has been reached; then
release the lever or pedal.
T R..
Bleed screw:
6 Nm (0.6 m • kg, 4.3 ft • lb)
i. Repeat steps (e) to (h) until of the air
bubbles have been removed from the
system.

õ

3 - 25
INSP
ADJ
FRONT BRAKE ADJUSTMENT
3. Install:
lProtector (rear brake)
lDiaphragm
lMaster cylinder cap
NOTE:
If bleeding is difficult, it may be necessary to
let the brake fluid system stabilize for a few
hours. Repeat the bleeding procedure when
the tiny bubbles in the system have disap-
peared.
j. Add brake fluid to the level line on the
reservoir.
WARNING
Check the operation of the brake after
bleeding the brake system.
EC362031
FRONT BRAKE ADJUSTMENT
1. Check:
lBrake lever position a
Standard brake lever position a:
82.5 mm (3.25 in)
2. Adjust:
lBrake lever position
Loosen the locknuts 1, then adjust the
lever position by changing their tighten-
ing position.
3. Tighten:
lLocknut
CAUTION:
Be sure to tighten the locknuts, as it will
cause poor brake performance.
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)