2003 YAMAHA WR 450F engine

2 - 28
SPECCABLE ROUTING DIAGRAM
1Throttle cable
2Brake hose
3Clamp
4Lights switch lead
5Hot starter cable
6Clutch cable
7Hose guide
8Clutch switch lead
9“ENGINE STOP” button
lead
0Trip meter cable
AMain switch lead
BTrip meter
CMain switch
DLights switch
EStart switch leadÅFasten the start switch lead and
lights switch lead to the handlebar
with a plastic band.
ıFasten the “ENGINE STOP” but-
ton lead and clutch switch lead to
the handlebar with the plastic
bands.
ÇPass the brake hose through the
hose guide.
ÎPass the start switch lead in front
of the main switch lead.
‰Fasten the start switch lead to the
handlebar with a plastic band.
ÏPass the hot starter cable and
lights switch lead between the
handle crown and coupler
bracket.ÌPass the throttle cables and clutch
cable between the handle crown
and trip meter.

SPEC
2 - 28
1Gasseilzug
2Bremsschlauch
3Klammer
4Lichtschalterleitung
5Heißstarter-Seilzug
6Kupplungsseilzug
7Schlauchführung
8Kupplungsschalterleitung
9Motorstoppschalter-Kabel
0Tageskilometerzählerkabel
AZündschalterleitung
BTageskilometerzähler
CHauptschalter
DLichtschalter
EStartschalterleitung
ÅDie Startschalterleitung und die Licht-
schalterleitung am Lenker mit einem
Plastikband befestigen.
ıDie Motorstoppschalterleitung und
Kupplungsschalterleitung mit den Pla-
stikbändern am Lenker befestigen.
ÇDen Bremsschlauch durch die
Schlauchführungen führen.
ÎDie Startschalterleitung vor der
Hauptschalterleitung verlegen.
‰Die Startschalterleitung am Lenker
mit einem Plastikband befestigen.
ÏDen Heißstarter-Seilzug und die
Lichtschalterleitung zwischen oberer
Gabelbrücke und Leitungssteckerbü-
gel verlegen.
ÌDie Gasseilzüge und die Kupplungs-
seilzüge zwischen oberer Gabelbrük-
ke und Tageskilometerzähler verle-
gen. 1Câble d’accélérateur
2Tuyau de frein
3Bride
4Câble de contacteur de feux
5Câble de démarrage à chaud
6Câble d’embrayage
7Guide de câble
8Câble de contacteur d’embrayage
9Câble de bouton d’arrêt du moteur
0Câble de compteur journalier
ACâble de coupe-circuit du moteur
BCompteur journalier
CCoupe-circuit du moteur
DContacteur de feux
ECâble de contacteur de démarrage
ÅAttacher le câble de contacteur de démar-
rage et le câble de contacteur de feux au
guidon avec une bande en plastique.
ıAttacher le câble du bouton d’arrêt du
moteur et le câble du contacteur
d’embrayage au guidon avec les bandes
en plastique.
ÇFaire passer le tuyau de frein par les gui-
des de tuyaux.
ÎFaire passer le câble de contacteur de
démarrage devant le câble du coupe-cir-
cuit.
‰Attacher le câble du contacteur de démar-
rage au guidon avec une bande en plasti-
que.
ÏFaire passer le câble de démarrage à
chaud et le câble de contacteur de feux
entre la couronne de guidon et le support
de raccord.
ÌFaire passer les câbles d’accélérateur et le
câble d’embrayage entre la couronne de
guidon et le compteur journalier.1Cable del acelerador
2Tubo del freno
3Abrazadera
4Cable del interruptor de las luces
5Cable de arranque en caliente
6Cable del embrague
7Guía del tubo
8Cable del interruptor del embrague
9Botón de parada del motor “ENGINE
STOP”.
0Cable del medidor de trayecto
ACable del interruptor principal
BMedidor de trayecto
CInterruptor principal
DInterruptor de las luces
ECable del interruptor de arranque
ÅSujete el cable del interruptor de arranque
y el cable del interruptor de las luces al
manillar con una banda plástica.
ıSujete el cable del botón de parada del
motor “ENGINE STOP” y el cable del
interruptor del embrague al manillar con
una banda plástica.
ÇPase el tubo del freno a través de las guías
del tubo.
ÎPase el cable del interruptor de arranque
por delante del cable del interruptor prin-
cipal.
‰Sujete el cable del interruptor de arranque
al manillar con una banda plástica.
ÏPase el cable de arranque en caliente y el
cable del interruptor de las luces entre la
tija del manillar y la ménsula del acopla-
dor.
ÌPase los cables del acelerador y el cable
del embrague entre la tija del manillar y el
medidor de trayecto.
CHEMINEMENT DES CABLES
KABELFÜHRUNG
DIAGRAMA DE RUTA DE CABLES

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
●

●

VALVES
Check the valve clearances
Inspect
Replace
●

●

●

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

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

●
Check for scratches and
wear.
CAMSHAFTS
Inspect
Replace
●

●
Inspect the camshaft sur-
face.
Inspect the decompres-
sion system
CAMSHAFT SPROCKETS
Inspect
Replace
●

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

●

●

●
Inspect crack
Inspect carbon deposits
and eliminate them.
PISTON RING
Inspect
Replace
●

●

●
Check ring end gap
PISTON PIN
Inspect
Replace
●

●

CYLINDER HEAD
Inspect and clean
●
Inspect carbon deposits
and eliminate them.
Change gasket
CYLINDER
Inspect and clean
Replace
●

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

●

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

●

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.1-14
Engine oilCheck that the oil level is correct. Check the crankcase and
frame oil line for leakage.P.3-14 ~ 18
Gear shifter and clutchCheck that gears can be shifted correctly in order and that the
clutch operates smoothly.P.3-10
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.3-26 ~ 32
ChainCheck chain slack and alignment. Check that the chain is lubri-
cated properly.P.3-33 ~ 36
WheelsCheck for excessive wear and tire pressure. Check for loose
spokes and have no excessive play.P.3-44 ~ 45
SteeringCheck that the handlebar can be turned smoothly and have no
excessive play.P.3-45 ~ 46
Front forks and rear shock
absorberCheck that they operate smoothly and there is no oil leakage. P.3-36 ~ 43
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.3-33
Lubrication Check for smooth operation. Lubricate if necessary. P.3-47
Bolts and nuts Check the chassis and engine for loose bolts and nuts. P.1-19
Lead connectorsCheck that the AC 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 - 5
INSP
ADJ
EC350000
ENGINE
COOLANT LEVEL INSPECTION
WARNING
Do not remove the radiator cap 1, drain
bolt and hoses when the engine and radia-
tor are hot. Scalding hot fluid and steam
may be blown out under pressure, which
could cause serious injury.
When the engine has cooled, place a thick
towel over the radiator cap, slowly rotate
the cap counterclockwise to the detent.
This procedure allows any residual pres-
sure to escape. When the hissing sound
has stopped, press down on the cap while
turning counterclockwise and remove it.
CAUTION:
Hard water or salt water is harmful to the
engine parts. You may use distilled water, if
you can’t get soft water.
1. Place the machine on a level place, and
hold it in an upright position.
2. Inspect:
Coolant level
Coolant level should be between the
maximum a and minimum b marks.
Coolant level is below the “LOW” level
line → Add soft water (tap water) up to
the proper level.
3. Start the engine and let it warm up for
several minutes.
4. Turn off the engine and check the coolant
level again.
NOTE:
Before checking the coolant level, wait a few
minutes until the coolant settles.
LOWFULLCOOLANT
a
b
COOLANT REPLACEMENT
WARNING
Do not remove the radiator cap when the
engine is hot.
ENGINE/COOLANT LEVEL INSPECTION/
COOLANT REPLACEMENT

3 - 6
INSP
ADJ
COOLANT REPLACEMENT
CAUTION:
Take care so that coolant does not splash
on painted surfaces. If it splashes, wash it
away with water.
1. Place a container under the engine.
2. Remove:
Seat
Refer to “SEAT, FUEL TANK AND
SIDE COVERS” section in the CHAP-
TER 4.
3. Disconnect:
Coolant reservoir hose 1
Drain the coolant completely.
4. Connect:
Coolant reservoir hoseLOWFULLCOOLANT1
5. Remove:
Engine guard 1
Coolant drain bolt 2
6. Remove:
Radiator cap
Drain the coolant completely.
7. Clean:
Cooling system
Thoroughly flush the cooling system
with clean tap water.
8. Install:
Copper washer
Coolant drain bolt
Engine guard
Bolt [engine guard (front)]
Bolt [engine guard (rear)]
New
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
T R..34 Nm (3.4 m · kg, 24 ft · lb)
T R..23 Nm (2.3 m · kg, 17 ft · lb)

3 - 7
INSP
ADJ
COOLANT REPLACEMENT
9. Fill:
Radiator
Engine
To specified level.
CAUTION:
Do not mix more than one type of ethyl-
ene glycol antifreeze containing corro-
sion inhibitors for aluminum engine.
Do not use water containing impurities or oil.
Recommended coolant:
High quality ethylene glycol
anti-freeze containing
anti-corrosion for
aluminum engine
Coolant 1 and water
(soft water) 2 mixing ratio:
50%/50%
Coolant capacity:
1.25 L (1.10 Imp qt, 1.32 US qt)
Handling notes of coolant:
The coolant is harmful so it should be han-
dled with special care.
WARNING
When coolant splashes to your eye.
Thoroughly wash your eye with water
and see your doctor.
When coolant splashes to your clothes.
Quickly wash it away with water and
then with soap.
When coolant is swallowed.
Quickly make him vomit and take him
to a doctor.
10. Install:
Radiator cap
11. Fill:
Coolant reservoir tank
Midway a between maximum and min-
imum marks on the tank.
LOWFULLCOOLANTa

3 - 8
INSP
ADJRADIATOR CAP INSPECTION/
RADIATOR CAP OPENING PRESSURE INSPECTION
12. Install:
Coolant reservoir cap
13. Start the engine and let it warm up for
several minutes.
14. Turn off the engine and inspect the cool-
ant level.
Refer to “COOLANT LEVEL INSPEC-
TION” section.
NOTE:
Before checking the coolant level wait a few
minutes until the coolant settles.
EC355000
RADIATOR CAP INSPECTION
1. Inspect:
Seal (radiator cap) 1
Valve and valve seat 2
Crack/damage → Replace.
Exist fur deposits 3 → Clean or
replace.
EC356001
RADIATOR CAP OPENING PRESSURE
INSPECTION
1. Attach:
Radiator cap tester 1 and adapter 2
NOTE:
Apply water on the radiator cap seal.
3Radiator cap
2. Apply the specified pressure.
Radiator cap tester:
YU-24460-01/90890-01325
Adapter:
YU-33984/90890-01352
Radiator cap opening pressure:
110 kPa (1.1 kg/cm2, 15.6 psi)