stop start YAMAHA YZ250F 2002 Owners Manual

GEN
INFO

1 - 1
DESCRIPTION
EC100000
GENERAL INFORMATION
EC110000
DESCRIPTION
1
Clutch lever
2
Decompression lever
3
Front brake lever
4
Throttle grip
5
Radiator cap
6
Fuel tank cap
7
Oil tank cap
8
Engine stop switch
9
Kickstarter crank
0
Fuel tank
A
Radiator
B
Coolant drain bolt
C
Rear brake pedal
D
Valve joint
E
Fuel cock
F
Cold starter knob
G
Hot starter knob (red)
H
Drive chain
I
Air filter
J
Shift pedal
K
Front fork
NOTE:


The machine you have purchased may differ
slightly from those shown in the following.

Designs and specifications are subject to
change without notice.

GEN
INFO

DESCRIPTION
FAHRZEUGBESCHREIBUNG
DESCRIZIONE
ALLGEMEINE
ANGABEN
FAHRZEUGBESCHREI-
BUNG
1
Kupplungshebel
2
Dekompressionshebel
3
Handbremshebel
4
Gasdrehgriff
5
Kühlerverschlußdeckel
6
Kraftstoffankverschluß
7
Öltankdeckel
8
Motorstoppschalter
9
Kickstarterhebel
0
Kraftstofftank
A
Kühler
B
Kühlmittel-Ablaßschraube
C
Fußbremshebel
D
Auslaufschutzventil
E
Kraftstoffhahn
F
Kaltstarterknopf
G
Heißstarterknopf (rot)
H
Antriebskette
I
Luftfilter
J
Schalthebel
K
Teleskopgabel
HINWEIS:


Leichte Modell-Abweichungen
möglich.

Änderungen an Design und techni-
schen Daten jederzeit vorbehalten.
RENSEIGNEMENTS
GENERAUX
DESCRIPTION
1
Levier d’embrayage
2
Levier de décompression
3
Levier de frein avant
4
Poignée des gaz
5
Bouchon de radiateur
6
Bouchon de réservoir de carburant
7
Bouchon du réservoir d’huile
8
Coupe-circuit du moteur
9
Kick
0
Réservoir de carburant
A
Radiateur
B
Boulon de vidange du liquide de
refroidissement
C
Pédale de frein arrière
D
Joint de robinet
E
Robinet de carburant
F
Bouton de démarrage à froid
G
Bouton de démarrage à chaud
(rouge)
H
Chaîne de transmission
I
Filtre à air
J
Sélecteur
K
Fourche avant
N.B.:


Votre machine diffère peut-être par-
tiellement de celle montrée sur ces
photos.

La conception et les caractéristiques
peuvent êtres changées sans préavis.
1 - 1
INFORMAZIONI
GENERALI
DESCRIZIONE
1
Leva della frizione
2
Leva della decompressione
3
Leva del freno anteriore
4
Manopola dell’acceleratore
5
Tappo del radiatore
6Tappo del serbatoio del carburante
7Tappo del serbatoio dell’olio
8Interruttore di arresto motore
9Pedivella di avviamento
0Serbatoio del carburante
ARadiatore
BBullone di scarico del refrigerante
CPedale del freno posteriore
DGiunto a valvola
ERubinetto del carburante
FManopola di avviamento a freddo
GManopola di avviamento a caldo
(rossa)
HCatena di trasmissione
IFiltro aria
JPedale del cambio
KForcella anteriore
NOTA:
Il veicolo acquistato potrebbe differire
leggermente da quelli illustrati qui di
seguito.
I modelli e le specifiche sono soggetti
a variazioni senza preavviso.
1

1 - 10
GEN
INFO
CONTROL FUNCTIONS
EC150000
CONTROL FUNCTIONS
ENGINE STOP SWITCH
The engine stop switch 1 is located on the left
handlebar. Continue pushing the engine stop
switch till the engine comes to a stop.
EC152000
CLUTCH LEVER
The clutch lever 1 is located on the left han-
dlebar; it disengages or engages the clutch.
Pull the clutch lever to the handlebar to disen-
gage 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 1 on
the left side of the engine.
KICKSTARTER CRANK
Rotate the kickstarter crank 1 away from the
engine. Push the starter down lightly with your
foot until the gears engage, then kick smoothly
and forcefully to start the engine. This model
has a primary kickstarter crank so the engine
can be started in any gear if the clutch is dis-
engaged. In normal practices, however, shift to
neutral before starting.
1

GEN
INFO
FONCTIONS DES COMMANDES
ARMATUREN UND DEREN FUNKTION
FUNZIONI DI COMANDO
ARMATUREN UND DE-
REN FUNKTION
MOTORSTOPPSCHALTER
Der Motorstoppschalter 1 befindet
sich auf der linken Seite des Len-
kers.
Den Motorstoppschalter gedrückt
halten, bis der Motor abstirbt.
KUPPLUNGSHEBEL
Der Kupplungshebel 1 befindet sich
auf der linken Seite des Lenkers und
dient zum Ein- und Auskuppeln. Zum
Ausrücken der Kupplung den Kupp-
lungshebel zum Lenkgriff ziehen; zum
Einrücken der Kupplung den Kupp-
lungshebel wieder freigeben. Zum
Auskuppeln den Kupplungshebel
zügig ziehen, beim Einkuppeln gefühl-
voll loslassen, um ein weiches Einrük-
ken der Kupplung zu gewährleisten.
FUSSSCHALTHEBEL
Erst das Getriebe erlaubt die Nut-
zung der Motorleistung in verschie-
denen Geschwindigkeitsbereichen,
so daß Anfahren, Bergauffahren und
schnelles Beschleunigen möglich
sind. Die Gänge dieses 5-Gang-
Getriebes werden über den Fuß-
schalthebel 1 linksseitig des Motors
bei ausgerückter Kupplung geschal-
tet.
KICKSTARTERHEBEL
Zum Anlassen des Motors den Kick-
starterhebel 1 ausschwenken und
langsam niedertreten, bis deutlicher
Widerstand spürbar wird; dann den
Kickstarterhebel schwungvoll durch-
treten. Dieses Modell ist mit einem
Primärkickstarter ausgerüstet, d. h.
der Motor kann auch bei eingelegtem
Gang angelassen werden – voraus-
gesetzt, daß die Kupplung ausge-
rückt ist. Normalerweise sollte
jedoch in den Leerlauf geschaltet
werden, bevor der Motor gestartet
wird.
FONCTIONS DES COM-
MANDES
COUPE-CIRCUIT DU MOTEUR
Le coupe-circuit du moteur 1 est situé à
la poignée gauche. Appuyer de façon
continue sur le coupe-circuit du moteur
jusqu’à ce que le moteur s’arrête.
LEVIER D’EMBRAYAGE
Le levier d’embrayage 1 est situé à la
poignée 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 démar-
rages doux, le levier doit être tiré rapide-
ment et relâché lentement.
PEDALE DE CHANGEMENT DE
VITESSE
Les 5 rapports de la boîte de vitesses à
prise constante sont idéalement échelon-
nés. Le changement de vitesse est com-
mandé par le sélecteur 1, situé du côté
gauche du moteur.
PEDALE DE KICK
Déployer la pédale de kick 1. Appuyer
légèrement sur la pédale jusqu’à ce que
les pignons se mettent en prise puis
l’actionner vigoureusement pour démar-
rer le moteur. Ce modèle est muni d’un
démarreur au pied primaire, de sorte
qu’on peut démarrer à n’importe quelle
vitesse à condition de débrayer. Toute-
fois, normalement, on remettra les vites-
ses au point mort avant la mise en
marche.
FUNZIONI DI COMANDO
INTERRUTTORE DI ARRESTO
DEL MOTORE
L’interruttore di arresto del motore 1 è
posto sul manubrio a sinistra. Tenere
premuto l’interruttore di arresto del
motore finché il motore non si arresta
completamente.
LEVA DELLA FRIZIONE
La leva della frizione 1 è posta sul
manubrio sinistro e impegna o disimpe-
gna la frizione. Tirare la leva della fri-
zione verso il manubrio per
disimpegnare la frizione e rilasciare la
leva per impegnare la frizione. La leva
va tirata rapidamente e rilasciata lenta-
mente per un avvio dolce e senza
“strappi”.
PEDALE DEL CAMBIO
I rapporti di trasmissione del cambio a 5
velocità sempre in presa sono distanziati
in maniera ideale. È possibile cambiare
le marce utilizzando il pedale del cambio
1 a sinistra del motore.
PEDIVELLA DI AVVIAMENTO
Far ruotare la pedivella di avviamento 1
allontanandola dal motore. Premere leg-
germente con il piede affinché il motore
non si impegna quindi spingere con deci-
sione per avviare il motore. Questo
modello è dotato di una pedivella di
avviamento in modo tale che è possibile
avviare il motore in qualunque marcia se
la frizione non è impegnata. Normal-
mente, però, passare in folle prima
dell’avvio.
1 - 10

1 - 12
GEN
INFO
CONTROL FUNCTIONS
EC158001
FUEL COCK
The fuel cock supplies fuel from the tank to
carburetor 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.
COLD STARTER KNOB
When cold, the engine requires a richer air-fuel
mixture for starting. A separate starter circuit,
which is controlled by the cold starter knob 1,
supplies this mixture. Pull the cold starter knob
out to open the circuit for starting. When the
engine has warmed up, push it in to close the
circuit.
HOT STARTER KNOB
The hot starter knob (red) 1 is used when
starting a warm engine.
Use the hot starter knob when starting the
engine again immediately after it was stopped
(the engine is still warm). Pulling out the hot
starter knob injects secondary air to thin the
air-fuel mixture temporarily, allowing the
engine to be started more easily.
CAUTION:
After the engine has started, be sure to
push the hot starter knob back in.

1 - 18
GEN
INFO
STARTING AND BREAK-IN
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 switch.
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.

GEN
INFO
NETTOYAGE ET RANGEMENT
REINIGUNG UND STILLEGUNG
PULIZIA ED IMMAGAZZINAGGIO
STILLEGUNG
Vor einer mehr als zweimonatigen
Stillegung sollten einige Schutzvor-
kehrungen getroffen werden, um
Schäden zu verhindern. Das Fahr-
zeug zuerst gründlich reinigen und
dann folgendermaßen zur Stillegung
vorbereiten:
1. Kraftstofftank, Kraftstoffleitun-
gen und Vergaser-Schwim-
merkammer entleeren.
2. Die Zündkerze herausschrau-
ben, ungefähr einen Teelöffel
Motoröl in die Kerzenbohrung
geben und die Zündkerze wie-
der hineinschrauben. Bei ge-
drücktem Motorstoppschalter
den Kickstarter mehrmals
durchtreten, um das Öl in der
Zylinderlaufbuchse zu vertei-
len.
3. Die Antriebskette lösen,
gründlich reinigen und dann
schmieren. Die Kette wieder
montieren oder in einem am
Rahmen befestigten Plastik-
beutel aufbewahren.
4. Alle Seilzüge ölen.
5. Das Fahrzeug ganz aufbok-
ken, um beide Räder vom Bo-
den abzuheben.
6. Eine Plastiktüte über die
Schalldämpferöffnung stül-
pen, um Eindringen von
Feuchtigkeit zu verhindern.
7. Bei Lagerung in extrem feuch-
ter oder salzhaltiger Luft auf
alle Metalloberflächen einen
dünnen Ölfilm auftragen. Je-
doch niemals Gummiteile oder
den Sitzbankbezug einölen.
HINWEIS:
Anfallende Reparaturen vor der Still-
legung ausführen. RANGEMENT
Si l’on remise la machine pour 60 jours
ou plus, il faut prendre des mesures de
conservation pour éviter sa détérioration.
Après un nettoyage soigné, préparer la
machine de la manière suivante:
1. Vider le réservoir, les conduites
d’essence et la cuve du carbura-
teur.
2. Déposer la bougie, verser une
cuillère à soupe d’huile moteur
SAE 10W-30 dans le trou de bou-
gie, et la remettre en place.
Coupe-circuit à la position arrêt,
donner plusieurs coups de kick
pour enduire le cylindre d’huile.
3. Déposer la chaîne, la nettoyer soi-
gneusement au dissolvant et
lubrifier. Remonter la chaîne ou
la ranger dans un sachet plastique
fermé fixé au cadre.
4. Lubrifier tous les câbles de com-
mande.
5. Mettre le cadre sur plots pour
soulever les roues du sol.
6. Fixer un sachet plastique sur la
sortie du pot d’échappement pour
éviter l’introduction d’humidité.
7. Si la machine est placée dans une
atmosphère humide ou marine,
enduire toutes les surfaces métal-
liques nues d’une fine couche
d’huile. Ne pas appliquer d’huile
sur les parties en caoutchouc ou
sur la selle.
N.B.:
Avant de ranger la machine, effectuer
toutes les réparations nécessaires.IMMAGAZZINAGGIO
Se il veicolo va immagazzinato 60 giorni
o oltre, è necessario prendere alcune
misure precauzionali per evitarne il dete-
rioramento. Dopo aver pulito accurata-
mente il veicolo, prepararlo nel modo
seguente:
1. Scaricare il serbatoio del carbu-
rante, le linee carburante e la
vaschetta del galleggiante del car-
buratore.
2. Rimuovere la candela, versare un
cucchiaio di olio motore SAE
10W-30 nel foro della candela e
reinserire la candela. Con l’inter-
ruttore di arresto del motore pre-
muto, agire sulla pedivella di
avviamento più volte in modo da
ricoprire d’olio le pareti dei cilin-
dri.
3. Rimuovere la catena di trasmis-
sione, pulirla accuratamente con
un solvente e lubrificarla. Rimon-
tarla o conservarla in un sacchetto
di plastica legato al telaio.
4. Lubrificare tutti i cavi dei
comandi.
5. Bloccare in alto il telaio in modo
da sollevare le ruote dal terreno.
6. Legare un sacchetto di plastica
sul tubo di scarico per impedire la
penetrazione dell’umidità.
7. Se il veicolo viene immagazzi-
nato in un ambiente umido o con
aria salmastra, ricoprire tutte le
superfici in metallo esposte con
un leggero strato d’olio. Non
applicare olio sui componenti in
gomma o al rivestimento della
sella.
NOTA:
Effettuare tutti gli eventuali interventi di
riparazione necessari prima di immagaz-
zinare il veicolo.
1 - 21

SPEC
2 - 11
MAINTENANCE SPECIFICATIONS
NOTE:
- marked portion shall be checked for torque tightening after break-in or before each race. Silencer M8 × 1.25 2 35 3.5 25
Silencer clamp M8 × 1.25 1 20 2.0 14
Crankcase M6 × 1.0 11 12 1.2 8.7
Crankcase bearing stopper M6 × 1.0 11 10 1.0 7.2
Crankcase bearing stopper (crankshaft) M6 × 1.0 4 10 1.0 7.2
Left crankcase cover M6 × 1.0 8 10 1.0 7.2
Right crankcase cover M6 × 1.0 8 10 1.0 7.2
Clutch cover M6 × 1.0 7 10 1.0 7.2
Crankcase oil drain bolt M10 × 1.25 1 20 2.0 14
Drive chain sprocket cover M6 × 1.0 2 8 0.8 5.8
Kick shaft ratchet wheel guide M6 × 1.0 2 12 1.2 8.7
Kickstarter crank M8 × 1.25 1 33 3.3 24
Primary drive gear M18 × 1.0 1 75 7.5 54
Clutch spring M6 × 1.0 5 8 0.8 5.8
Clutch boss M16 × 1.0 1 60 6.0 43
Push lever shaft M6 × 1.0 1 10 1.0 7.2
Drive sprocket M18 × 1.0 1 75 7.5 54
Drive axle oil seal stopper M6 × 1.0 2 10 1.0 7.2
Segument M8 × 1.25 1 30 3.0 22
Shift guide M6 × 1.0 2 10 1.0 7.2
Stopper lever M6 × 1.0 1 10 1.0 7.2 Part to be tightened Thread size Q’tyTightening torque
Nm m·kg ft·lb

3 - 12
INSP
ADJ
AIR FILTER CLEANING
2. Adjust:
Decompression lever free play
AIR FILTER CLEANING
NOTE:
Proper air filter maintenance is the biggest key
to preventing premature engine wear and
damage.
CAUTION:
Never run the engine without the air filter
element in place; this would allow dirt and
dust to enter the engine and cause rapid
wear and possible engine damage.
1. Remove:
Seat
Fitting bolt 1
Washer 2
Air filter element 3
Air filter guide 4
2. Clean:
Air filter element
Clean them with solvent.
NOTE:
After cleaning, remove the remaining solvent
by squeezing the element.
CAUTION:
Do not twist the element when squeezing
the element.
Leaving too much of solvent in the ele-
ment may result in poor starting. Adjustment steps:
Loosen the locknut 1.
Turn the adjuster 2 in or out until the
adjustment is suitable.
Tighten the locknut.
CAUTION:
After the adjustment, start the engine
and make sure that the engine does not
stop when the handlebar is turned fully
both ways. If the decompression cable is
too tense, the engine will stop by the
decompression system.

3 - 19
INSP
ADJ
ENGINE IDLING SPEED ADJUSTMENT
1. Start the engine and thoroughly warm it
up.
2. Attach:
Inductive tachometer
To spark plug lead.
3. Adjust:
Engine idling speed
Adjustment steps:
Adjust the pilot screw.
Refer to “PILOT SCREW ADJUSTMENT”
section.
Turn the throttle stop screw 1 until the
engine runs at the lowest possible speed.
To increase idle speed → Turn the throt-
tle stop screw 1 in a.
To decrease idle speed → Turn the throt-
tle stop screw 1 out b.
Inductive tachometer:
YU-8036-B
Engine tachometer:
90890-03113
Engine idling speed:
1,900 ~ 2,100 r/min
VALVE CLEARANCE INSPECTION AND
ADJUSTMENT
NOTE:
The valve clearance should be adjusted
when the engine is cool to the touch.
The piston must be at Top Dead Center
(T.D.C.) on compression stroke to check or
adjust the valve clearance.
1. Remove:
Seat
Fuel tank
Refer to “SEAT, FUEL TANK AND
SIDE COVERS” section in the CHAP-
TER 4.
2. Drain:
Coolant
Refer to “COOLANT REPLACEMENT”
section.
ENGINE IDLING SPEED ADJUSTMENT/
VALVE CLEARANCE INSPECTION AND ADJUSTMENT