engine YAMAHA YZ250LC 2002 User Guide

1-4
IMPORTANT INFORMATION
GEN
INFO
EC133000
GASKETS, OIL SEALS AND O-RINGS
1. All gaskets, oil seals, and O-rings should be
replaced when an engine is overhauled. All
gasket surfaces, oil seal lips, and O-rings
must be cleaned.
2. Properly oil all mating parts and bearings
during reassembly. Apply grease to the oil
seal lips.
EC134000
LOCK WASHERS/PLATES AND COTTER
PINS
1. All lock washers/plates 1and cotter pins
must be replaced when they are removed.
Lock tab(s) should be bent along the bolt or
nut flat(s) after the bolt or nut has been
properly tightened.
EC135001
BEARINGS AND OIL SEALS
1. Install the bearing (s) 1and oil seal (s) 2
with their manufacturer’s marks or numbers
facing outward. (In other words, the
stamped letters must be on the side
exposed to view.) When installing oil seal(s),
apply a light coating of light-weight lithium
base grease to the seal lip(s). Oil the bear-
ings liberally when installing.
cC
Do not use compressed air to spin the
bearings dry. This causes damage to the
bearing surfaces.
EC132000
ALL REPLACEMENT PARTS
1. We recommend to use Yamaha genuine
parts for all replacements. Use oil and/or
grease recommended by Yamaha for
assembly and adjustment.
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1-8
SPECIAL TOOLS
GEN
INFO
Part number Tool name / How to use IIIustration
YU-33975, 90890-01403 Ring nut wrenchYU-33975 90890-01403
This tool is used when tighten the steering ring nut
to specification.
YM-1423, 90890-01423 Damper rod holder
YM-1423 90890-01423
Use this tool to remove and install the damper rod.
YM-01442, 90890-01442 Fork seal driver
YM-01442 90890-01442
This tool is used when install the fork oil seal.
YU-3112-C, 90890-03112 Yamaha pocket tester
YM-3112-C 90890-03112
Use this tool to inspect the coil resistance,
output voltage and amperage.
YU-8036-B Inductive tachometer
YU-8036-B 90890-03113
90890-03113 Engine tachometer
This tool is needed for observing engine rpm.
YM-91042, 90890-04086 Clutch holding tool
YM-91042 90890-04086
This tool is used to hold the clutch when removing
or installing the clutch boss securing nut.
YM-34487 Dynamic spark tester
YM-34487 90890-06754
90890-06754 Ignition checker
This instrument is necessary for checking the igni-
tion system components.
ACC-QUICK-GS-KT Quick gasket
®ACC-QUICK-GS-KT 90890-85505
90890-85505 YAMAHA Bond No. 1215
This sealant (Bond) is used for crankcase mating
surface, etc.
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1-9
CONTROL FUNCTIONS
GEN
INFO
EC150000
CONTROL FUNCTIONS
EC151000
“ENGINE STOP” BUTTON
The “ENGINE STOP” button 1is located on the
left handlebar. Continue pushing the “ENGINE
STOP” button till the engine comes to a stop.
EC152000
CLUTCH LEVER
The clutch lever 1is located on the left handle-
bar; it disengages or engages the clutch. Pull
the clutch lever to the handlebar to disengage
the clutch, and release the lever to engage the
clutch. The lever should be pulled rapidly and
released slowly for smooth starts.
EC153000
SHIFT PEDAL
The gear ratios of the constant-mesh 5 speed
transmission are ideally spaced. The gears can
be shifted by using the shift pedal 1on the left
side of the engine.
EC154000
KICK STARTER
Rotate the kick starter 1away from the engine.
Push the starter down lightly with your foot until
the gears engage, then kick smoothly and force-
fully to start the engine. This model has a prima-
ry kick starter so the engine can be started in
any gear if the clutch is disengaged. In normal
practices, however, shift to neutral before start-
ing.
EC155001
THROTTLE GRIP
The throttle grip 1is located on the right han-
dlebar; it accelerates or decelerates the engine.
For acceleration, turn the grip toward you; for
deceleration, turn it away from you.
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1-9
FONCTIONS DES COMMANDES
BEDIENUNGSELEMENTE
FUNZIONI DEI COMANDI
GEN
INFO
FONCTIONS DES
COMMANDES
BOUTON D’ARRET DE MOTEUR
“ENGINE STOP”
Ce bouton d’arrêt de moteur “ENGINE
STOP” 1est situé sur le guidon
gauche. Continuer à appuyer sur le bou-
ton d’arrêt de moteur “ENGINE STOP”
jusqu’a que ce le moteur s’arrête.
LEVIER D’EMBRAYAGE
Le levier d’embrayage 1est situé sur
le guidon gauche et permet d’embrayer
ou de débrayer. Tirer le levier
d’embrayage vers le guidon pour
débrayer et relâcher le levier pour
embrayer. Pour des démarrages doux,
le levier doit être tiré rapidement et
relâché lentement.
PEDALE DE CHANGEMENT DE
VITESSE
Les 5 rapports pour de la boîte de
vitesses à prise constante sont idéale-
ment échelonnés. Le changement de
vitesse est commandé par le sélecteur à
pédale 1situé du côté gauche du
moteur.
KICKSTARTER
Déployer la pédale de démarreur au
pied 1. Appuyer légèrement sur la
pédale jusqu’à ce que les pignons se
mettent en prise puis l’actionner vigou-
reusement pour démarrer le moteur. Ce
modèle est muni d’un démarreur au
pied primaire, de sorte qu’on peut
démarrer sur n’importe quelle vitesse à
condition de débrayer. Toutefois, nor-
malement, on remettra les vitesses au
point mort avant la mise en marche.
POIGNEE DES GAZ
La poignée des gaz 1est située sur le
guidon droit; elle permet d’accélérer ou
de décélérer le moteur. Pour une accé-
lération, tourner la poignée vers soi;
pour une décélération, la tourner de
l’autre côté.
BEDIENUNGSELEMENTE
MOTORSTOPPKNOPF „ENGINE
STOP“
Dieser Motorstoppknopf „ENGINE
STOP“ 1befindet sich am linken
Lenkerrohr.
Den Motorstoppknopf „ENGINE
STOP“ drücken, bis der Motor
abstirbt.
KUPPLUNGSHEBEL
Der Kupplungshebel 1befindet sich
am linken Lenkerrohr und dient zum
Aus- bzw. Einrücken der Kupplung.
Den Kupplungshebel bis zum Lenker-
rohr durchziehen, um die Kupplung
auszurücken; den Hebel wieder frei-
geben, sobald die Kupplung wieder
eingerückt werden soll. Der Hebel
sollte schnell durchgezogen, aber
langsam freigegeben werden, um ein
ruckfreies Anfahren zu gewährleisten.
FUSSSCHALTHEBEL
Das Untersetzungsverhältnis dieses 5
Gang Synchrongetriebes ist optimal
abgestimmt, um bestes Leistungsver-
mögen bei allen Fahrbedingungen zu
garantieren. Das Einlegen der einzel-
nen Gänge erfolgt mittels Fußschalt-
hebel 1, angebrancht an der linken
Seite des Motors.
KICKSTARTER
Den Kickstarter 1vom Motor weg-
schwenken. Den Kickstarter langsam
niedertreten, bis die Zahnräder einra-
sten; danach den Kickstarter
schwungvoll durchtreten, um den
Motor anzulassen. Dieses Modell ist
mit einem Primärkickstarter ausgerü-
stet, d.h. der Motor kann auch bei ein-
gelegtem Gang angelassen werden,
vorausgesetzt, daß die Kupplung aus-
gerückt wird. Normalerweise sollte
jedoch in den Leerlauf geschaltet wer-
den, bevor der Motor gestartet wird.
GASDREHGRIFF
Der Gasdrehgriff 1ist am rechten
Lenkerrohr angeordnet; mit diesem
Gasdrehgriff wird die Drehzahl des
Motors erhöht bzw. reduziert. Für eine
Drehzahlerhöhung (Beschleunigung)
den Gasdrehgriff gegen sich drehen,
wogegen für eine Drehzahlreduzie-
rung der Gasdrehgriff von sich wegge-
dreht werden muß.
IC150000
FUNZIONI DEI COMANDI
IC151000
PULSANTE “ARRESTO
MOTORE”
Il pulsante “ARRESTO MOTORE” 1
è situato sul manubrio sinistro. Conti-
nuare a premere il pulsante “ARRE-
STO MOTORE” finché il motore non
si arresta.
IC152000
LEVA DI COMANDO DELLA
FRIZIONE
La leva di comando della frizione 1è
situata sul manubrio sinistro; disinnesta
o innesta la frizione. Tirare la leva di
comando della frizione verso il manu-
brio per disinnestare la frizione e lascia-
re andare la leva per innestare la frizio-
ne. La leva dovrebbe essere tirata rapi-
damente e lasciata andare lentamente
per partenze dolci.
IC153000
PEDALE DI COMANDO DEL
CAMBIO
I rapporti di trasmissione della trasmis-
sione a 5 marce a ingranamento costan-
te sono distanziati in maniera ideale. Si
possono cambiare le marce usando il
pedale di comando del cambio 1sul
lato sinistro del motore.
IC154000
PEDIVELLA DELLA MESSA IN
MOTO
Ruotare la pedivella della messa in
moto 1allontanandola dal motore.
Spingere leggermente la pedivella verso
il basso con il piede finché le marce
non si innestano, quindi scalciare senza
strappi e con forza per avviare il moto-
re. Questo modello ha una pedivella
primaria della messa in moto, quindi il
motore può essere avviato in qualsiasi
marcia se la frizione è disinnestata.
Nella prassi normale, però, mettere in
folle prima di avviare.
IC155001
MANOPOLA DELL’ACCELERA-
TORE
La manopola dell’acceleratore 1è
situata sul manubrio destro; accelera o
decelera il motore. Per l’accelerazione,
ruotare la manopola verso il guidatore;
per la decelerazione, ruotarla lontano
dal guidatore.
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1-10
CONTROL FUNCTIONS
GEN
INFO
EC156000
FRONT BRAKE LEVER
The front brake lever 1is located on the right
handlebar. Pull it toward the handlebar to acti-
vate the front brake.
EC157000
REAR BRAKE PEDAL
The rear brake pedal 1is located on the right
side of the machine. Press down on the brake
pedal to activate the rear brake.
EC158001
FUEL COCK
The fuel cock supplies fuel from the tank to car-
buretor while filtering the fuel. The fuel cock has
the two positions:
OFF: With the lever in this position, fuel will not
flow. Always return the lever to this posi-
tion when the engine is not running.
ON: With the lever in this position, fuel flows to
the carburetor. Normal riding is done with
the lever in this position.
EC159000
STARTER KNOB (CHOKE)
When cold, the engine requires a richer air-fuel
mixture for starting. A separate starter circuit,
which is controlled by the starter knob 1, sup-
plies this mixture. Pull the starter knob out to
open the circuit for starting. When the engine
has warmed up, push it in to close the circuit.
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1-12
FUEL AND ENGINE MIXING OIL
GEN
INFO
EC160051
FUEL AND ENGINE MIXING OIL
Mix oil with the gas at the ratio specified below.
Always use fresh, name-brand gasoline, and mix
the oil and gas the day of the race. Do not use
premix that is more than a few hours old.
NOTE:
If knocking or pinging occurs, use a different
brand of gasoline or higher octane grade.
cC
Never mix two types of oil in the same
batch; clotting of the oil could result. If you
wish to change oil types, be sure to drain
the fuel tank and the carburetor float bowl
of old premix prior to filling with the new
type.
Fuel tank capacity:
8.0 L (1.76 Imp gal, 2.11 US gal)
Mixing oil
Recommended oil:
Yamalube “2-R”
(Yamalube racing 2-cycle oil)
Mixing ratio: 30 : 1
If unavailable, use an equivalent
type of oil.
Recommended fuel:
Except for ZA:
Premium unleaded gasoline
only with a research octane
number of 95 or higher.
For ZA:
Premium gasoline
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1-13
STARTING AND BREAK-IN
GEN
INFO
EC190000
STARTING AND BREAK-IN
cC
Before starting the machine, perform the
checks in the pre-operation check list.
w
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.
EC191001
STARTING A COLD ENGINE
1. Shift the transmission into neutral.
2. Turn the fuel cock to “ON” and full open the
starter knob (CHOKE).
3. With the throttle completely closed start the
engine by kicking the kick starter forcefully
with firm stroke.
4. Run the engine at idle or slightly higher until
it warms up: this usually takes about one or
two minutes.
5. The engine is warmed up when it responds
normally to the throttle with the starter knob
(CHOKE) turned off.
cC
Do not warm up the engine for extended peri-
ods.
EC193001
STARTING A WARM ENGINE
Do not operate the starter knob (CHOKE). Open
the throttle slightly and start the engine by kick-
ing the kick starter forcefully with firm stroke.
cC
Observe the following break-in procedures
during initial operation to ensure optimum
performance and avoid engine damage.
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1-14
STARTING AND BREAK-IN
GEN
INFO
EC194001
BREAK-IN PROCEDURES
1. Before starting the engine, fill the fuel tank
with a break-in oil-fuel mixture as follows.
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.
4. Operate the machine in the lower gears at
moderate throttle openings for five to eight
minutes. Stop and check the spark plug
condition; it will show a rich condition during
break-in.
5. Allow the engine to cool. Restart the engine
and operate the machine as in the step
above for five minutes. Then, very briefly
shift to the higher gears and check full-throt-
tle response. Stop and check the spark
plug.
6. After again allowing the engine to cool,
restart and run the machine for five more
minutes. Full throttle and the higher gears
may be used, but sustained full-throttle
operation should be avoided. Check the
spark plug condition.
7. Allow the engine to cool, remove the top
end, and inspect the piston and cylinder.
Remove any high spots on the piston with
#600 grit wet sandpaper. Clean all compo-
nents and carefully reassemble the top end.
8. Drain the break-in oil-fuel mixture from the
fuel tank and refill with the specified mix.
9. Restart the engine and check the operation
of the machine throughout its entire operat-
ing range. Stop and check the spark plug
condition. Restart the machine and operate
it for about 10 to 15 more minutes. The
machine will now be ready to race.
Mixing oil: Mixing ratio:
Yamalube “2-R” 15:1
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1-14
MISE EN MARCHE ET RODAGE
STARTEN UND EINFAHREN
AVVIAMENTO E RODAGGIO
GEN
INFO
EINFAHRVORGÄNGE
1. Vor dem Starten des Motors, den
Kraftstofftank für das Einfahren mit
einem Benzin/Öl-Gemisch wie dar-
gestellt füllen.
2. Die unter „Prüfungen vor Inbetrieb-
nahme“ aufgeführten Kotrollen aus-
führen.
3. Den Motor starten und warmlaufen
lassen. Die Leerlaufdrehzahl kon-
trollieren und die Funktion der
Bedienungselemente und des
Motorstoppknopfes „ENGINE
STOP“ prüfen.
4. Die Maschine in den unteren Gän-
gen bei gemäßigter Drosselöffnung
füf fünf bis acht Minuten fahren. Den
Motor danach abschalten und den
Zustand der Zündkerze kontrollie-
ren; während des Einfahrens sollte
die Zündkerze leicht verölt (fettes
Gemisch) sein.
5. Den Motor abkühlen lassen. Den
Motor wieder starten und die
Maschine für etwa fünf Minuten
unter den gleichen Bedingungen
betreiben, wie sie oben beschrieben
wurden. Danach jeweils kurz in die
höheren Gänge schalten und das
Ansprechen auf Vollgas kontrollie-
ren. Den Motor wieder abschalten
und nochmals die Zündkerze kon-
trollieren.
6. Den Motor abkühlen lassen, danach
wieder starten und die Maschine
nochmals für fünf Minuten betreiben.
Nun dürfen die höheren Gänge
auch bei Vollgas eingesetzt werden,
wobei jedoch längeres Vollgasfah-
ren zu vermeiden ist. Anschließend
den Zustand der Zündkerze prüfen.
7. Den Motor abkühlen lassen, den
Zylinderkopf ausbauen und Kolben
und Zylinder kontrollieren. Den Kol-
ben ggf. mit Schmirgelleinen der
Körnung 600 glätten. Alle Bauteile
reinigen und vorsichtig wieder ein-
bauen.
8. Das Benzin/Öl-Gemisch für das Ein-
fahren aus dem Kraftstofftank ent-
leeren und das vorgeschriebene
Gemisch einfüllen.
9. Den Motor starten und die Betriebs-
bedingungen der Maschine im
gesamten Betriebsbereich überprü-
fen. Den Motor abschalten und den
Zustand der Zündkerze kontrollie-
ren. Den Motor wieder starten und
die Maschine für etwa 10 bis 15
Minuten betreiben. Danach ist die
Maschine einsatzbereit für Rennen.
PROCEDURE DE RODAGE
1. Avant de lancer le moteur, rem-
plissez le réservoir d’un mélange
essence-huile de rodage de propor-
tion si dessous.
2. Exécutez le contrôle avant utilisa-
tion de la machine.
3. Lancez le moteur et laissez-le se
réchauffer. Vérifiez le régime de
ralenti, le fonctionnement des
commandes et l’efficacité du bou-
ton d’arrêt du moteur “ENGINE
STOP”.
4. Pilotez la machine sur les rapports
inférieurs et à régime modéré
durant les cinq à huit premières
minutes. Arrêtez-vous et vérifiez
l’état de la bougie; elle devrait
donner des indices de richesse
durant le rodage.
5. Laissez le moteur se refroidir.
Remettez le moteur en marche et
pilotez comme ci-dessus pendant
cinq minutes. Passez brièvement
sur les rapports supérieurs et véri-
fiez la réponse à pleine accéléra-
tion. Arrêtez-vous et revérifiez la
bougie.
6. A nouveau, laissez le moteur se
refroidir. Redémarrez et pilotez
pendant cinq nouvelles minutes.
Cette fois, vous pouvez rouler à
pleins gaz sur les rapports supé-
rieurs, mais évitez une marche
soutenue à pleine vitesse. Vérifiez
l’état de la bougie.
7. Laissez le moteur se refroidir,
déposez la culasse et le cylindre, et
examinez piston et cylindre. Elimi-
nez les points élevés au papier de
verre humide No. 600. Nettoyez
tous les éléments puis remontez
soigneusement le moteur.
8. Videz le mélange essence-huile de
rodage du réservoir et remplissez-
le du mélange prescrit.
9. Remettez le moteur en marche et
vérifiez son fonctionnement à tous
les régimes. Arrêtez et vérifiez la
bougie. Relancez le moteur et pilo-
tez la machine pendant 10 à 15
minutes supplémentaires. Elle sera
alors prête pour la course.IC194001PROCEDURE DI RODAGGIO
1. Prima di avviare il motore, riempi-
re il serbatorio del carburante con
una miscela di olio-carburante per
rodaggio come segue.
2. Eseguire i controlli sul veicolo
prima del funzionamento.
3. Avviare e scaldare il motore. Con-
trollare il numero di giri al minimo
e controllare il funzionamento dei
comandi e del pulsante “ARRE-
STO MOTORE”.
4. Azionare il veicolo alle marce
basse con aperture moderate della
valvola a farfalla per cinque-otto
minuti. Arrestarlo e controllare le
condizioni della candela; durante il
rodaggio presenterà condicche.
5. Far raffreddare il motore. Riavvia-
re il motore e far funzionare il vei-
colo come descritto nel punto pre-
cedente per cinque minuti. Quindi,
passare per brevissimo tempo alle
marce alte e controllare la risposta
con la valvola a farfalla completa-
mente aperta. Arrestarlo e control-
lare la candela.
6. Dopo avere fatto raffreddare anco-
ra il motore, riavviare e far girare
il veicolo per altri cinque minuti.
Si possono usare la valvola a far-
falla completamente aperta e le
marce alte, ma si dovrebbe evitare
un funzionamento prolungato con
la valvola a farfalla completamen-
te aperta. Controllare le condizioni
della candela.
7. Far raffreddare il motore, togliere
l’estremità superiore e ispezionare
il pistone e il cilindro. Togliere
eventuali irregolarità sul pistone
con carta vetrata bagnata di grana
No. 600. Pulire tutti i componenti
e rimontare con cautela l’estremità
superiore.
8. Scaricare la miscela di olio-carbu-
rante di rodaggio dal serbatoio del
carburante e riempirlo con la
miscela specificata.
9. Riavviare il motore e controllare il
funzionamento del veicolo per
tutta la gamma di funzionamento.
Arrestarlo e controllare le condi-
zioni della candela. Riavviare il
veicolo e farlo funzionare per altri
10-15 minuti circa. Il veicolo sarà
ora pronto per la gara.
Huile de Proportions
Mélange: de Mélange:
Yamalube
“2-R” 15 : 1Olio per Rapporto di
miscela: miscelazione:
Yamalube
“2-R” 15 : 1Mischöl: Misch-
verhältnis:
Yamalube
„2-R“ 15 : 1
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1-15
STARTING AND BREAK-IN
GEN
INFO
cC
9
After the break-in or before each race, you
must check the entire machine for loose fit-
tings and fasteners as per “TORQUE-
CHECK POINTS”.
Tighten all such fasteners as required.
9When 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 AND GEARS:
These parts require about 30 minutes of
break-in operation at half-throttle or less.
Observe the condition of the engine careful-
ly during operation.
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