2001 YAMAHA YZ426F oil

2 - 23
SPEC
ãPass the neutral switch lead and
CDI magneto lead over the middle
radiator mounting boss. Then, pass
the decompression cable under the
middle radiator mounting boss and
along the left side of the neutral
switch lead and CDI magneto lead.
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 cush-
ion bracket (frame).Fasten the ignition coil lead (in the
sub wire harness) to the frame
and cut off the tie end.
Pass the carburetor breather
hoses and overflow hose so that
all there hoses do not contact the
rear shock absorber.

CABLE ROUTING DIAGRAM

2 - 24
SPECCABLE ROUTING DIAGRAM
1Clamp
2Ignition coil
3High tension cord
4CDI unit
5CDI unit band
6Throttle cable (pull)
7Throttle cable (return)
8Radiator (left)
9Radiator breather hose
0Radiator (right)
ACDI unit stay (frame)Fasten the ignition coil lead to the
frame with a plastic band.
õFasten the ignition coil and ground
lead to the frame with the bolt.
‚Pass 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.
ëPass the throttle cables over the
high tension cord.
äPass the throttle cables along the
outer side of the CDI unit leads.
ìUsing a plastic locking tie, clamp
to the frame the CDI unit leads at
their protecting tubes.íPass the throttle cables between
the top radiator mounting boss
and middle radiator mounting
boss.
îPass the CDI unit leads over the
top radiator mounting boss.
éCross the pull and return throttle
cables before the radiator.
ïPass the throttle cables through
the cable guide.
ðPass the radiator breather hose
between the frame and the radia-
tor without pinching it.
ñPass the radiator breather hose
behind the decompression cable.
÷Insert the CDI unit band over the
CDI unit stay (frame) as far as
possible.

3 - 1
INSP
ADJ

MAINTENANCE INTERVALS
EC300000
REGULAR INSPECTION AND ADJUSTMENTS
MAINTENANCE INTERVALS
The following schedule is intended as a general guide to maintenance and lubrication. Bear in mind
that such factors as weather, terrain, geographical location, and individual usage will alter the
required maintenance and lubrication intervals. If you are a doubt as to what intervals to follow in
maintaining and lubricating your machine, consult your Yamaha dealer.
ItemAfter
break-inEvery
race
Every
third
(or
500 km)Every
fifth
(or
1,000 km)
As re-
quiredRemarks
ENGINE OIL
Replace
c

c

OIL FILTER
Clean
cc

VALVES
Check the valve clearances.
Inspect
Replace
c

c

c

c
The engine must be cold.
Check the valve seats
and valve stems for wear.
VALVE SPRINGS
Inspect
Replace
c

c
Check the free length and
the tilt.
VALVE LIFTERS
Inspect
Replace
c

c
Check for scratches and
wear.
CAMSHAFTS
Inspect
Replace
c

c
Inspect the camshaft sur-
face.
CAMSHAFT SPROCKETS
Inspect
Replace
c

c
Check for wear on the
teeth and for damage.
PISTON
Inspect
Clean
Replace
c

c

c

c
Inspect crack
Remove carbon
PISTON RING
Inspect
Replace
c

c

c
Check ring end gap
PISTON PIN
Inspect
Replace
c

c

CYLINDER HEAD
Inspect and clean
c
Remove carbon
Change gasket
CYLINDER
Inspect and clean
Replace
c

c
Inspect score marks
Inspect wear
CLUTCH
Inspect and adjust
Replace
c

c

c
Inspect housing, friction
plate, clutch plate and
spring
TRANSMISSION
Inspect
Replace bearing
c

c



3

3 - 2
INSP
ADJ

MAINTENANCE INTERVALS
SHIFT FORK, SHIFT CAM, GUIDE BAR
Inspect
c
Inspect wear
ROTOR NUT
Retighten
c

c

MUFFLER
Inspect and retighten
Clean
Replace
c

c

c

c
* Whichever comes first
CRANK
Inspect and clean
c

c

CARBURETOR
Inspect, adjust and clean
c

c
When using a high-pres-
sure washer, make sure
that water does not enter
the accelerator pump.
SPARK PLUG
Inspect and clean
Replace
c

c

c

DRIVE CHAIN
Lubricate, slack, alignment
Replace
c

c

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
c

c

c

c

c
Every two years
OUTSIDE NUTS AND BOLTS
Retighten
c

c
Refer to “STARTING
AND BREAK-IN” section
in the CHAPTER 1.
AIR FILTER
Clean and lubricate
Replace
c

c

c
Use foam air-filter oil
OIL STRAINER (frame)
Clean
c

FRAME
Clean and inspect
c

c

FUEL TANK, COCK
Clean and inspect
c

c

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

c

c

c

c

c

c

c

c
Every one year
FRONT FORKS
Inspect and adjust
Replace oil
Replace oil seal
c

c

c

c

c
Suspension oil “01”
FRONT FORK OIL SEAL AND DUST
SEAL
Clean and lube
c

c
Lithium base grease ItemAfter
break-inEvery
race
Every
third
(or
500 km)Every
fifth
(or
1,000 km)
As re-
quiredRemarks


3

3 - 3
INSP
ADJ

MAINTENANCE INTERVALS
REAR SHOCK ABSORBER
Inspect and adjust
Lube
Retighten
c

c

c

c

c

c Molybdenum disulfide
grease
CHAIN GUARD AND ROLLERS
Inspect
c c
SWINGARM
Inspect and retighten
c c
RELAY ARM, CONNECTING ROD
Inspect and lube
c c Molybdenum disulfide
grease
STEERING HEAD
Inspect free play and retighten
Clean and lube
Replace bearing
c c
c
c Lithium base grease
TIRE, WHEELS
Inspect air pressure, wheel run-out,
tire wear and spoke looseness
Retighten sprocket bolt
Inspect bearings
Replace bearings
Lubricate
c
c
c
c
c
c
c
Lithium base grease
THROTTLE, CONTROL CABLE
Check routing and connection
Lubricate
c
c
c
c Yamaha cable lube or
SAE 10W-30 motor oil ItemAfter
break-inEvery
race
Every
third
(or
500 km)Every
fifth
(or
1,000 km)As re-
quiredRemarks

INSP
ADJ

PROGRAMME D’ENTRETIEN
FOURCHE AVANT
Contrôler et régler
Changer l’huile
Changer la bague d’étanchéité
c
cc
c
c
Huile de suspension “01”
BAGUE D’ETANCHEITE ET JOINT
ANTIPOUSSIERE DE FOURCHE
AVANT
Nettoyer et lubrifier
cc
Graisse à base de lithium
AMORTISSEUR ARRIERE
Contrôler et régler
Lubrifier
Resserrer
c
cc
ccc
Graisse au bisulfure de
molybdène
GUIDE-CHAINE ET ROULEAU
Contrôler
cc
BRAS OSCILLANT
Contrôler et resserrer
cc
BRAS RELAIS, BIELLE
Contrôler et lubrifier
cc
Graisse au bisulfure de
molybdène
TETE DE FOURCHE
Contrôler le jeu
Nettoyer et lubrifier
Changer le roulement
cc
c
c
Graisse à base de lithium
PNEU, ROUES
Contrôler la pression de gonflage, le voile
de roue et l’usure des pneus et la tension
des rayons
Resserrer les boulons de la roue dentée
Contrôler les roulements
Changer les roulements
Graisser
c
cc
c
c
cc
Graisse à base de lithium
ACCELERATEUR, CABLES DE COM-
MANDE
Contrôler le cheminement et le branche-
ment
Graisser
c
cc
c
Yamaha lube pour câble ou
Huile moteur SAE 10W-30 PartieAprès
rodageChaque
courseChaque
3ème (ou
500 km)Chaque
5ème (ou
1.000 km)Si
néces-
saireRemarques
3 - 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.
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.1-13 ~ 14
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. —
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.1-18
Lead connectorsCheck that the CDI magneto, CDI unit, and ignition coil are con-
nected tightly.P.1-6
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 - 7
INSP
ADJ
RADIATOR CAP INSPECTION
CAUTION:
lDo not mix more than one type of ethyl-
ene glycol antifreeze containing corro-
sion inhibitors for aluminum engine.
lDo not use water containing impurities or
oil.
7. Install:
lRadiator cap
Start the engine and warm it up for a
several minutes.
8. Check:
lCoolant level
Coolant level low ® Add coolant. Handling notes of coolant:
The coolant is harmful so it should be han-
dled with special care.
WARNING
lWhen coolant splashes to your eye.
Thoroughly wash your eye with water
and see your doctor.
lWhen coolant splashes to your clothes.
Quickly wash it away with water and
then with soap.
lWhen coolant is swallowed.
Quickly make him vomit and take him
to a doctor.
EC355000
RADIATOR CAP INSPECTION
1. Inspect:
lSeal (radiator cap) 1
lValve and valve seat 2
Crack/damage ® Replace.
Exist fur deposits 3 ® Clean or
replace.