engine YAMAHA YZ450F 2003 Owner's Manual

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GEN
INFO
STARTING AND BREAK-IN
STARTING AND BREAK-IN
WARNING
Never start or run the engine in a closed
area. The exhaust fumes are poisonous;
they can cause loss of consciousness and
death in a very short time. Always operate
the machine in a well-ventilated area.
CAUTION:
The carburetor on this motorcycle has a
built-in accelerator pump. Therefore,
when starting the engine, do not operate
the throttle or the spark plug will foul.
Unlike a two-stroke engine, this engine
cannot be kick started when the throttle is
open because the kick starter may kick
back. Also, if the throttle is open the air/
fuel mixture may be too lean for the
engine to start.
Before starting the machine, perform the
checks in the pre-operation check list.
STARTING A COLD ENGINE
1. Inspect the coolant level.
2. Turn the fuel cock to “ON”.
3. Shift the transmission into neutral.
4. Fully open the cold starter knob 1.
5. Kick the kick starter.
WARNING
Do not open the throttle while kicking the
kick starter. Otherwise, the kick starter may
kick back.

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GEN
INFO
STARTING AND BREAK-IN
6. Return the cold starter knob to its original
position and run the engine at 3,000 ~
5,000 r/min for 1 or 2 minutes.
NOTE:
Since this model is equipped with an accelera-
tor pump, if the engine is raced (the throttle
opened and closed), the air/fuel mixture will be
too rich and the engine may stall. Also unlike a
two-stroke engine, this model can idle.
CAUTION:
Do not warm up the engine for extended
periods of time.

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GEN
INFO
STARTING AND BREAK-IN
STARTING A WARM ENGINE
Do not operate the cold starter knob and throt-
tle. Pull the hot starter lever 1 and start the
engine by kicking the kick starter forcefully with
a firm stroke.
As soon as the engine starts, release the hot
starter lever to close the air passage.
Restarting an engine after a fall
Pull the hot starter lever and start the engine.
As soon as the engine starts, release the hot
starter lever to close the air passage.
The engine fails to start
Pull the hot starter lever all the way out and
while holding the lever, kick the kick starter 10
to 20 times to clear the engine.
Then, restart the engine.
Refer to “Restarting an engine after a fall”.
* Operate the throttle grip before kick starting.
CAUTION:
Observe the following break-in procedures
during initial operation to ensure optimum
performance and avoid engine damage.
Throttle
grip oper-
ation*Cold
starter
knobHot
starter
lever
Starting a cold engine
Air temperature = less than
5 ˚C (41 ˚F)Open 3
or 4 timesON OFF
Air temperature = more
than 5 ˚C (41 ˚F)None ON OFF
Air temperature (normal tem-
perature) = between 5 ˚C
(41 ˚F) and 25 ˚C (77 ˚F)None ON/OFF OFF
Air temperature = more
than 25 ˚C (77 ˚F)None OFF OFF
Starting an engine after a long
period of timeNone ON OFF
Restarting a warm engine None OFF ON
Restarting an engine after a fall None OFF ON

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GEN
INFO
BREAK-IN PROCEDURES
1. Before starting the engine, fill the fuel
tank with the fuel.
2. Perform the pre-operation checks on the
machine.
3. Start and warm up the engine. Check the
idle speed, and check the operation of
the controls and the “ENGINE STOP”
button. Then, restart the engine and
check its operation within no more than 5
minutes after it is restarted.
4. Operate the machine in the lower gears
at moderate throttle openings for five to
eight minutes.
5. Check how the engine runs when the
motorcycle is ridden with the throttle 1/4
to 1/2 open (low to medium speed) for
about one hour.
6. Restart the engine and check the opera-
tion of the machine throughout its entire
operating range. Restart the machine
and operate it for about 10 to 15 more
minutes. The machine will now be ready
to race.
CAUTION:
After the break-in or before each race,
you must check the entire machine for
loose fittings and fasteners as per
“TORQUE-CHECK POINTS”.
Tighten all such fasteners as required.
When any of the following parts have
been replaced, they must be broken in.
CYLINDER AND CRANKSHAFT:
About one hour of break-in operation is
necessary.
PISTON, RING, VALVES, CAMSHAFTS
AND GEARS:
These parts require about 30 minutes of
break-in operation at half-throttle or less.
Observe the condition of the engine care-
fully during operation.
STARTING AND BREAK-IN

GEN
INFO
EINFAHRVORSCHRIFTEN
1. Vor dem Anlassen des Motors volltan-
ken.
2. Die “ROUTINEKONTROLLE VOR
FAHRTBEGINN” ausführen.
3. Den Motor anlassen und warmlaufen las-
sen. Dabei die Leerlaufdrehzahl überwa-
chen und die Funktion der Bedienungs-
elemente sowie des Motorstoppschalters
“ENGINE STOP” prüfen. Innerhalb der
nächsten fünf Minuten den Motor wieder
anlassen und die folgenden Schritte aus-
führen.
4. Die Maschine fünf bis acht Minuten lang
bei mäßiger Gasdrehgrifföffnung in den
unteren Gängen fahren.
5. Den Motorbetrieb etwa eine Stunde lang
bei 1/4 bis 1/2 geöffnetem Gasdrehgriff
(niedrige bis mittlere Geschwindigkeit)
überprüfen.
6. Den Motor erneut anlassen und den Mo-
torbetrieb im gesamten Betriebsbereich
überprüfen. Den Motor abschalten und
noch einmal anlassen und die Maschine
10 bis 15 Minuten betreiben. Danach ist
die Maschine für Rennen einsatzbereit.
ACHTUNG:
Nach dem Einfahren und vor jedem Ren-
nen die Schraubverbindungen gemäß der
Tabelle “ANZUGSMOMENTE KONTROL-
LIEREN” auf festen Sitz prüfen und vor-
schriftsmäßig anziehen.
Nach der Erneuerung eines der folgenden
Teile muß die Maschine erneut eingefah-
ren werden.
- ZYLINDER UND KURBELWELLE
Etwa eine Stunde Einfahrzeit
- KOLBEN, KOLBENRINGE, VENTILE,
NOKKENWELLEN UND -RÄDER:
Etwa 30 Minuten Einfahrzeit bei oder un-
ter Halbgas (Sorgfältig den Motorbetrie-
büberprüfen.)
MISE EN MARCHE ET RODAGE
ANLASSEN UND EINFAHREN
PROCEDURE DE RODAGE
1. Avant de mettre le moteur en marche, faire le
plein d’essence.
2. Effectuer les contrôles avant utilisation de la
machine.
3. Lancer le moteur et le laisser se réchauffer.
Vérifier le régime de ralenti, le fonctionnement
des commandes et l’efficacité du bouton
d’arrêt du moteur “ENGINE STOP”. Remettre
ensuite le moteur en marche et vérifier son
fonctionnement dans les 5 minutes maximum.
4. Piloter la machine sur les rapports inférieurs
et à régime modéré durant les cinq à huit pre-
mières minutes. S’arrêter et vérifier l’état de
la bougie; elle devrait donner des indices de
richesse durant le rodage.
5. Vérifier le fonctionnement du moteur à une
ouverture des gaz de 1/4 à 1/2 (petite à
moyenne vitesse) pendant environ 1 heure.
6. Remettre le moteur en marche et vérifier son
fonctionnement à tous les régimes. Arrêter et
vérifier la bougie. Relancer le moteur et pilo-
ter la machine pendant 10 à 15 minutes sup-
plémentaires. Elle sera alors prête pour la
course.
ATTENTION:
Après le rodage ou avant chaque course, il faut
vérifier toutes les fixations et serrages comme
indiqué dans “POINTS DE VERIFICATION
DE COUPLE DE SERRAGE”.
Serrer toutes ces fixations comme requis.
Après avoir remplacé les pièces suivantes, un
nouveau rodage est nécessaire.
CYLINDRE ET VILEBREQUIN:
Une heure environ de rodage est nécessaire.
PISTONS, SEGMENTS, SOUPAPES, ARBRES
A CAMES:
Ces pièces nécessitent un rodage de 30 minutes
environ à une ouverture des gaz de maximum
1/2. Surveiller attentivement l’état du moteur
pendant la marche.
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GEN
INFO
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TORQUE-CHECK POINTS
TORQUE-CHECK POINTS
NOTE:
Concerning the tightening torque, refer to
“MAINTENANCE SPECIFICATIONS” section
in the CHAPTER 2.
Frame to rear frame
Fuel tank to frame
Silencer to rear frame
Frame to engine
Engine bracket to engine
Engine bracket to frame
Steering shaft to frame
Steering shaft to handle crown
Handle crown to handlebar
Front fork to handle crown
Front fork to under bracket
Assembly of links
Link to frame
Link to shock absorber
Link to swingarm
Shock absorber to frame
Tightening of pivot shaft
Tightening of front axle
Tightening of axle holder
Tightening of rear axle
Wheel to sprocket
Caliper to front fork
Brake disc to wheel
Tightening of union bolt
Master cylinder to handlebar
Tightening of air bleeder
Brake pedal to frame
Brake disc to wheel
Tightening of union bolt
Master cylinder to frame
Tightening of air bleeder
Fuel tank to fuel cock
Tightening of oil hose clamp Frame construction
Combined seat and tank
Exhaust system
Engine mounting
Steering Steering shaft to
handlebar
Suspension Front Steering shaft to front
fork
Rear For link type
Rear Installation of shock
absorber
Rear Installation of swing-
arm
Wheel Installation of wheel Front
Rear
Brake Front
Rear
Fuel system
Lubrication system

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GEN
INFO
CLEANING AND STORAGE
EC1B0000
CLEANING AND STORAGE
EC1B1000
CLEANING
Frequent cleaning of your machine will
enhance its appearance, maintain good overall
performance, and extend the life of many com-
ponents.
1. Before washing the machine, block off
the end of the exhaust pipe to prevent
water from entering. A plastic bag
secured with a rubber band may be used
for this purpose.
2. If the engine is excessively greasy, apply
some degreaser to it with a paint brush.
Do not apply degreaser to the chain,
sprockets, or wheel axles.
3. Rinse the dirt and degreaser off with a
garden hose; use only enough pressure
to do the job.
CAUTION:
Excessive hose pressure may cause water
seepage and contamination of wheel bear-
ings, front forks, brakes and transmission
seals. Many expensive repair bills have
resulted from improper high pressure
detergent applications such as those avail-
able in coin-operated car washers.
4. After the majority of the dirt has been
hosed off, wash all surfaces with warm
water and a mild detergent. Use an old
toothbrush to clean hard-to-reach places.
5. Rinse the machine off immediately with
clean water, and dry all surfaces with a
soft towel or cloth.
6. Immediately after washing, remove
excess water from the chain with a paper
towel and lubricate the chain to prevent
rust.
7. Clean the seat with a vinyl upholstery
cleaner to keep the cover pliable and
glossy.

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GEN
INFO
CLEANING AND STORAGE
8. Automotive wax may be applied to all
painted or chromed surfaces. Avoid com-
bination cleaner-waxes, as they may con-
tain abrasives.
9. After completing the above, start the
engine and allow it to idle for several min-
utes.
EC1B2001
STORAGE
If your machine is to be stored for 60 days or
more, some preventive measures must be
taken to avoid deterioration. After cleaning the
machine thoroughly, prepare it for storage as
follows:
1. Drain the fuel tank, fuel lines, and the
carburetor float bowl.
2. Remove the spark plug, pour a table-
spoon of SAE 10W-30 motor oil in the
spark plug hole, and reinstall the plug.
With the engine stop switch pushed in,
kick the engine over several times to coat
the cylinder walls with oil.
3. Remove the drive chain, clean it thor-
oughly with solvent, and lubricate it.
Reinstall the chain or store it in a plastic
bag tied to the frame.
4. Lubricate all control cables.
5. Block the frame up to raise the wheels off
the ground.
6. Tie a plastic bag over the exhaust pipe
outlet to prevent moisture from entering.
7. If the machine is to be stored in a humid
or salt-air environment, coat all exposed
metal surfaces with a film of light oil. Do
not apply oil to rubber parts or the seat
cover.
NOTE:
Make any necessary repairs before the
machine is stored.

SPEC

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GENERAL SPECIFICATIONS
EC200000
SPECIFICATIONS
EC211000
GENERAL SPECIFICATIONS
Model name: YZ450FR (USA)
YZ450F (EUROPE)
YZ450F(R) (CDN, AUS, NZ, ZA)
Model code number: 5TA1 (USA)
5TA2 (EUROPE)
5TA4 (CDN, AUS, NZ, ZA)
Dimensions:
Overall length 2,171 mm (85.5 in)
Overall width 827 mm (32.6 in)
Overall height 1,303 mm (51.3 in)
Seat height 995 mm (39.2 in)
Wheelbase 1,485 mm (58.5 in)
Minimum ground clearance 371 mm (14.6 in)
Basic weight:
With oil and full fuel tank 113.0 kg (249 lb)
Engine:
Engine type Liquid cooled 4-stroke, DOHC
Cylinder arrangement Single cylinder, forward inclined
Displacement 449 cm
3

(15.8 Imp oz, 15.2 US oz)
Bore
×
stroke 95.0
×
63.4 mm (3.74
×
2.50 in)
Compression ratio 12.5 : 1
Starting system Kick starter
Lubrication system: Dry sump
Oil type or grade:
Engine oil (For USA and CDN)
At 5 ˚C (40 ˚F) or higher
Å

Yamalube 4 (20W-40) or SAE 20W-40 type SG
motor oil (Non-Friction modified)
At 15 ˚C (60 ˚F) or lower
ı

Yamalube 4 (10W-30) or SAE 10W-30 type SG
motor oil (Non-Friction modified) and/or
Yamalube 4-R (15W-50) (Non-Friction modi-
fied)
(Except for USA and CDN)
API “SG” or higher grade
-20
-4-10
140
3010
5020
6830
8640 50
104
122°CTemp.
°F
10W-30
10W-40
20W-40
20W-50
15W-40

SPEC

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GENERAL SPECIFICATIONS
Oil capacity:
Engine oil
Periodic oil change 1.0 L (0.88 Imp qt, 1.06 US qt)
With oil filter replacement 1.1 L (0.97 Imp qt, 1.16 US qt)
Total amount 1.2 L (1.06 Imp qt, 1.27 US qt)
Coolant capacity (including all routes): 1.2 L (1.06 Imp qt, 1.27 US qt)
Air filter: Wet type element
Fuel:
Type Premium unleaded gasoline only with a research
octane number of 95 or higher.(Except for ZA)
Premium gasoline (For ZA)
Tank capacity 7.0 L (1.54 Imp gal, 1.85 US gal)
Carburetor:
Type FCR MX39
Manufacturer KEIHIN
Spark plug:
Type/manufacturer CR8E/NGK (resistance type)
Gap 0.7 ~ 0.8 mm (0.028 ~ 0.031 in)
Clutch type: Wet, multiple-disc
Transmission: USA, CDN, ZA,
AUS, NZEUROPE
Primary reduction system Gear
←
Primary reduction ratio 62/22 (2.818)
←
Secondary reduction system Chain drive
←
Secondary reduction ratio 48/14 (3.429) 47/14 (3.357)
Transmission type Constant mesh,
4-speed
←
Operation Left foot operation
←
Gear ratio: 1st 27/14 (1.929)
←
2nd 25/16 (1.563)
←
3rd 23/18 (1.278)
←
4th 21/20 (1.050)
←
Chassis:
Frame type Semi double cradle
Caster angle 27.2˚
Trail 118 mm (4.65 in)
Tire:
Type With tube
Size (front) 80/100-21 51M (For USA, CDN, ZA, AUS, NZ
and F)
80/100-21 51R (For EUROPE except F)
Size (rear) 110/90-19 62M (For USA, CDN, ZA, AUS, NZ
and F)
110/90-19 NHS (For EUROPE except F)
Tire pressure (front and rear) 100 kPa (1.0 kgf/cm
2

, 15 psi)

2