engine YAMAHA YZ250LC 2002 Owner's Guide
Page 118 of 584
2-14
CABLE ROUTING DIAGRAMSPEC
1Ground lead 
2Ignition coil lead
3Clamp
4Wireharness
5CDI magneto lead
6YPVS breather hose
7Radiator breather hose
8Cable guide
9“ENGINE STOP” button lead
0Brake hose
APass the “ENGINE STOP” but-
ton lead on the inside of the
ignition coil lead and ground
lead.BClamp the “ENGINE STOP” but-
ton lead, ground lead, ignition
coil lead, wireharness and CDI
magneto lead with the clamp
ends downward.
In so doing, clamp the “ENGINE
STOP” button lead at its coupler
and do not allow the CDI mag-
neto lead to slacken.
CPass the radiator breather hose
outside the engine bracket and
inside the down-tube.Pass the
radiator breather hose inside
the CDI magneto lead.
DClamp the CDI magneto lead,
radiator breather hose and
YPVS breather hose. In so
doing, clamp the CDI magneto
lead at the rear of the down-
tube with the clamp ends for-
ward.EClamp the radiator breather
hose and CDI magneto lead at
the rear of the down-tube with
the clamp ends outward.
FPass the radiator breather hose
and CDI magneto lead in front
of the radiator hose.
GPass the radiator breather hose
between the frame and radiator.
HAlign the top of the brake hose
neck with the brake hose holder
bottom.
IPass the brake hose in front of
the axle boss,then fit it into the
hose groove so that the brake
hose does not contact the nut
(wheel axle).
JFit the brake hose into the guide
on the protector.
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2-14
SCHEMA DE CHEMINEMENT DES CABLES
KABELFÜHRUNGSÜBERSICHTPLAN
DIAGRAMMA DEL PASSAGGIO DEI CAVISPEC
1Massekabel
2Zündspulekabel
3Klemme
4kalbelbaum
5Leitungskabel des CDI - Magnetzün-
ders
6YPVS - Belüftungsschlauch
7Kühler - Belüftungsschlauch
8Kabelführung
9Leitungskabel des Motorstoppknopfes
„ENGINE STOP”
0Bremsschlauch
ALeitung des „ENGINE STOP”-Knopfs
an der Innenseite der Zündspulenlei-
tung und der Erdleitung durchführen.
B„ENGINE STOP“ Leitung, Erdleitung,
Zündspulenleitung, Kabelbaum und
CDI-Magnetleitung mit den Enden der
Verschlussklemmen nach unten fest-
klemmen.
Dabei die Leitung des „ENGINE
STOP”-Knopfs an ihrem Stecker fest-
klemmen und CDI-Magnetleitung nicht
durchhängen lassen.
C
An der Außenseite der Motoraufhängung
und an der Innenseite des Abwärtsrohrs.
Kühlerentlüfterschlauch an der Innenseite
der CDI-Magnetleitung durchführen.
DCDI-Magnetleitung, Kühlerentlüfter-
schlauch und YPVS-Entlüfterschlauch fest-
klemmen. Dabei wird die CDI-Magnetlei-
tung hinten am Abwärtsrohr festgeklemmt,
mit den Klemmenenden nach vorne.
EKühlerentlüfterschlauch und CDI-
Magnetleiter hinten am Ablaßrohr und
mit den Klemmenenden nach außen
festklemmen.
F
Kühlerentlüfterrohr und CDI-Magnetlei-
tung vor dem Kühlerschlauch durch-
führen.
GKühlerlüfterschlauch zwischen dem
Rahmen und dem Kühler durchführen.
HOberes Teil des Kabelschlauchhalses
mit dem Boden der Kabelschlauchhalte-
rung ausrichten.
I
Den Bremsschlauch vor der Achsnabe
durchführen und danach in die Schlauchnut
einsetzen, so daß der Bremsschlauch die
Mutter (Radacnse) nicht berührt.
JDen Bremsschlauch in die Führung am
Schutz einsetzen.
1Fil de masse
2Fil de bobine d’allumage
3Bride
4Faisceau de fils
5Fil de magnéto CDI
6Tube de reniflad YPVS
7Tuyau de reniflard de radiateur
8Guide de câble
9Fil de bouton d’arrêt du moteur “ENGI-
NE STOP”
0Tuyau de frein
AFaites passer le fil du bouton d’arrêt du
moteur “ENGINE STOP” à l’intérieur du
fil de la bobine d’allumage et du fil de
masse.
BBridez le fil du bouton d’arrât du moteur
“ENGINE STOP”, le fil de masse, le fil
de la bobine d’allumage, le faisceau de
fils et le fil de magnéto CDI en orientant
les extrémités de la bride vers le bas.
Ce faisant, bridez le fil du bouton d’arrêt
du moteur “ENGINE STOP” à son rac-
cord et ne laissez pas pendre le fil de
magnéto CDI.
CA l’extérieur du support du moteur et à
l’intérieur du tube inférieur. Faites passer
le tuyau reniflard du radiateur à l'inté-
rieur du fil de magnéto CDI.
DBridez le fil de magnéto CDI, le tuyau
reniflard du radiateur et le tuyau reniflard
YPVS. Ce faisant, bridez le fil de magné-
to CDI à l’arrière du tube inférieur avec
les extrémités de la bride orientées vers
l’avant.
EBridez le tuyau reniflard du radiateur et
le fil de magnéto CDI à l’arrière du tube
inférieur avec les extrémités de la bride
vers l’extérieur.
FFaites passer le tuyau reniflard du radia-
teur et le fil de magnéto CDI devant la
durit du radiateur.
GFaites passer le tuyau du reniflard entre
le cadre et le radiateur.
HAligner le dessus du col du tuyau de
frein sur la base du support du tuyau de
frein.
IFaire passer le tuyau de frein à l’avant du
bossage d’essieu, puis l’insérer dans la
cannelure de sorte qu’il ne touche pas
l’écrou (axe de roue).
JFaire rentrer le tuyau de frein dans le
guide sur le protecteur.1Conduttore di terra
2Conduttore de la bobina di accencsione
3Brida
4Complesso conduttori
5Conduttore del magneto CDI
6Sfiato YPVS
7Sfiato del radiatore
8Guida per cavi
9Conduttore del pulsante “ARRESTO
MOTORE”
0Tubo flessibile del freno
APassare il conduttore del pulsante
"ARRESTO MOTORE" all'interno del
conduttore della bobina d'accensione e
del conduttore di terra.
BAgganciare il conduttore del pulsante
"ARRESTO MOTORE", il conduttore di
terra, il conduttore della bobina d'accen-
sione, il complesso conduttori e il con-
duttore del magnete CDI con le estremità
della fascia di serraggio rivolte verso il
basso. Nel farlo, agganciare il conduttore
del pulsante "ARRESTO MOTORE" al
suo accoppiatore e non lasciare che il
conduttore del magnete CDI faccia
gioco.
CAll’esterno della brida del motore e
all’interno del tubo discendente. Far passare
lo sfiato del radiatore all’interno del condut-
tore del magnete CDI.
DFissare il conduttore del magnete CDI, lo
sfiato del radiatore e lo sfiato YPVS.
Nell’effettuare questa operazione, fissare il
conduttore del magnete CDI sul retro del
tubo discendente con le estremità della
fascia rivolte in avanti.
EFissare il tubo di sfiato del radiatore ed il
conduttore dei magneti CDI alla parte
posteriore del tubo con le estremità della
fascia di serraggio rivolte verso l’esterno.
FFar scorrere il tubo di sfiato del radiatore e
il conduttore del magnete CDI davanti al
tubo del radiatore.
GFar passare il tubo di sfiato del radiatore
tra il telaio e il radiatore.
HAllineare la cima del manicotto del tubo
flessibile del freno con la parte bassa del
supporto del tubo flessibile del freno.
IFar passare il tubo flessibile del freno
davanti al mozzo dell’asse, quindi inserirlo
nella scanalatura per tubo flessibile in modo
che il tubo flessibile del freno non tocchi il
dado (asse della ruota).
JInserire il tubo flessibile del freno nella
guida sul dispositivo di protezione.
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2-15
CABLE ROUTING DIAGRAMSPEC
1Clutch cable
2Cable guide
3Ground lead
4Clamp
5Wireharness
6High tension cord
7Ignition coil
8Radiator breather hose
9“ENGINE STOP” button lead
0Throttle cable 
qEngine bracketAPass the clutch cable into the
cable guide.
BClamp the clutch cable, high
tension cord and wireharness at
the protector of the high tension
cord so that the clamp passes
with its ends downward, as
shown.
CPosition the CDI magneto lead
coupler between the radiators.
DClamp the wireharness to the
right engine bracket.
EClamp the high tension cord,
throttle cable and wireharness
with the clamp ends downward,
so that the high tension cord
does not contact the engine
bracket installation nuts.FFasten the ground lead together
with the front installation portion
of the ingnition coil.
GPass the radiator breather hose
at the rear of the radiator hose.
HPosition the throttle cable,
“ENGINE STOP” button lead
and clutch cable as shown.
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2-15
SCHEMA DE CHEMINEMENT DES CABLES
KABELFÜHRUNGSÜBERSICHTPLAN
DIAGRAMMA DEL PASSAGGIO DEI CAVISPEC
1Kupplungskabel
2Kabelführung
3Massekabel
4Klemme
5Kabelbaum
6Hochspannungskabel
7Zündspule
8Kühlerentlüfterschlauch
9Leitungskabel des Motorstoppknopfes
„ENGINE STOP”
0Gasseil
qMotorhalterung
ADas Kupplungskabel in die Kabel-
führung einführen.
BKupplungskabel, Hochspannungs-
schnur und Kabelbaum so am Schutz
der Hochspannungsschnur festklem-
men, dass die Verschlussklemme, mit
den Enden nach unten, durchgeführt
wird.
CCDI-Magnetleitungsstecker zwischen
den Kühlern anbringen.
DKabelbaum an der rechten Motorhalte-
rung festklemmen.
EHochspannungsschnur, Gaskabel und
Kabelbaum mit den Enden der Ver-
schlussklemme nach unten so festklem-
men, dass die Hochspannungsschnur
nicht mit den Einbauschrauben der
Motorhalterung in Berührung gelangt.
FDas Massekabel gemeinsam mit dem
vorderen Befestigungsteil der Zündspu-
le befestigen.
GKühlerlüfterschlauch hinter dem Kühler-
schlauch durchführen.
HGaskabel, „ENGINE STOP“ Leitung
und Kupplungskabel anordnen, wie
gezeigt.1Câble d’embrayage
2Guide de câble
3Fil de masse
4Bride
5Faisceau de fils
6Cordon de haute-tension
7Bobine d’allumage
8Tuyau de reniflard de radiateur
9Fil de bouton d’arrêt du moteur “ENGI-
NE STOP”
0Câble d’accélérateur
qSupport du moteur
AFaire passer le tuyau de réserve dans le
guide de tuyau.
BBridez le câble d’embrayage, le cordon
de haute tension et le faisceau de fils sur
la protection du cordon de haute tension
de façon à ce que la bride soit orientée
avec ses extrémités vers le bas comme
illustré.
CPositionnez le raccord du fil de magnéto
CDI entre les radiateurs.
DBridez le faisceau de fils sur le support
droit du moteur.
EBridez le cordon de haute tension, le
câble d’accélérateur et le faisceau de fils
en orientant les extrémités de la bride
vers le bas de façon à ce que le cordon de
haute tension ne soit pas en contact avec
les écrous de montage du support du
moteur.
FFixer le fil de masse avec la partie avant
de fixation de la bobine d’allumage.
GFaites passer le tuyau de reniflard du
radiateur à l’arrière du tuyau du radia-
teur.
HPositionnez le câble d’accélérateur, le fil
du bouton d’arrât du moteur “ENGINE
STOP” et le câble d’embrayage comme
illustré.1Cavo della frizione
2Guida per cavi
3Conduttore di terra
4Brida
5Complesso conduttori
6Cavo ad alta tensione
7Bobina di accensione
8Tubo di sfiato del radiatore
9Conduttore del pulsante “ARRESTO
MOTORE”
0Cavo dell’acceleratore
qStaffa del motore
AFar passare il cavo della frizione nella
guida per cavi.
BAgganciare il cavo della frizione, il cavo
ad alta tensione e il complesso conduttori
alla protezione del cavo ad alta tensione,
con la fascia di serraggio passata con le
estremità rivolte verso il basso, come
illustrato.
CPosizionare l’accoppiatore del conduttore
del magnete CDI tra i radiatori.
DAgganciare il complesso conduttori alla
staffa destra del motore.
EAgganciare il cavo ad alta tensione, il
cavo dell'acceleratore e il complesso con-
duttori con le estremità della fascia di
serraggio rivolte verso il basso, in modo
che il cavo ad alta tensione non entri in
contatto con i dadi d'installazione della
staffa del motore.
FFissare il conduttore di terra con la parte
della bobina di accensione installata
anteriormente.
GFar passare il tubo di sfiato del radiatore
dietro al tubo del radiatore.
HPosizionare come illustrato il cavo del-
l'acceleratore, il conduttore del pulsante
"ARRESTO MOTORE" e il cavo della
frizione.
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SPEC
2-17
CABLE ROUTING DIAGRAM
1Brake hose
2Master cylinder
3“ENGINE STOP” button lead
4“ENGINE STOP” button
5Throttle cable
6Clutch cable
7Clamp
8Cable guideAInstall the brake hose so that its pipe portion 
directs as show and lightly touches the 
projection on the master cylinder.
BPass the “ENGINE STOP” button lead in 
the middle of the clutch holder.
CPass the clutch cable in front of the throttle 
cable.
DClamp the “ENGINE STOP” button lead to 
the handlebar to 3 clicks.
EPass the brake hose in front of the number 
plate and through the cable guide.
FCross the clutch cable and throttle cable 
over the number plate boss.
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SPEC
2-17
SCHEMA DE CHEMINEMENT DES CABLES
KABELFÜHRUNGSÜBERSICHTPLAN
DIAGRAMMA DEL PASSAGGIO DEI CAVI
1Bremsschlauch
2Hauptbremszylinder
3Leitungskabel des Motorstoppknopfes
„ENGINE STOP“
4Motorstoppknopf „ENGINE STOP“
5Gasseil
6Kupplungskabel
7Klemme
8Kabelführung
ADen Bremsschlauch so einbauen, daß
sein Rohrteil gemäß Abbildung ange-
ordnet ist und den Überstand am
Hauptbremszylinder leicht berührt.
BDas Leitungskabel des Motorstopp-
knopfes „ENGINE STOP“ in der Mitte
des Kupplungshalters durchführen.
CDas Kupplungsseil vor dem Gasseil
durchführen.
DKabel des Motorausschaltknopfes
„ENGINE STOP“ am Lenker festklem-
men mit 3 klicks.
EDen Bremsschlauch vor dem Num-
mernschild und durch die Kabelführung
durchführen.
FDas Kupplungsseil und das Gasseil
über der Nummernschild-Befesti-
gungsnabe überkreuzen.1Tuyau de frein
2Maître-cylindre
3Fil de bouton d’arrêt du moteur “ENGI-
NE STOP”
4Bouton d’arrêt du moteur “ENGINE
STOP”
5Câble d’accélérateur
6Câble d’embrayage
7Bride
8Guide de câble
åIstaller la tuyau de frein de manière que
la partie avec le tuyau soit dirigée
comme indipué et touche légèrement la
saillie sur le maîtrecylindre.
∫Faire passer le fil de bouton d’arrêt du
moteur “ENGINE STOP” au centre du
support d’embrayage.
çFaire passer le câble d’embrayage devant
le câble d’accélérateur.
∂Fixer le fil du bouton d’arrêt du “ENGI-
NE STOP” sur le guidon (3 déclics).
´Faire passer le tuyau de frein devant la
plaque d’immatriculation et à travers le
guide de câble.
ƒCroiser le câble d’embrayage et le câble
d’accélérateur sur le bossage de fixation
de la plaque minéralogique.1Tubo flessibile del freno
2Cilindro principale
3Conduttore del pulsante “ARRESTO
MOTORE”
4Pulsante “ARRESTO MOTORE”
5Cavo dell’acceleratore
6Cavo della frizione
7Nastro
8Guida per cavi
åInstallare il tubo flessibile del freno in
modo che la sua parte di tubo sia rivolta
come illustrato e tocchi leggermente la
sporgenza sul cilindro principale.
∫Far passare il conduttore del pulsante
“ARRESTO MOTORE” nel mezzo del
supporto della frizione.
çFar passare il cavo della frizione davanti
al cavo dell’acceleratore.
∂Bloccare il conduttore del pulsante
“ARRESTO MOTORE” sul manubrio
dopo 3 scatti.
´Far passare il tubo flessibile del freno
davanti alla targa e attraverso la guida
per cavi.
ƒIncrociare il cavo della frizione e il cavo
dell’acceleratore sopra il mozzo della
targa.
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3-4
PRE-OPERATION INSPECTION AND MAINTENANCE
INSP
ADJ
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.
EC321000
GENERAL INSPECTION AND MAINTENANCE
Item Routine Page
Coolant Check that coolant is filled up to the radiator filler cap.
Check the cooling system for leakage.P3-5~9
Fuel Check that a fresh mixture of oil and gasoline is filled in
the fuel tank. Check the fuel line for leakage.P1-12
Transmission oil Check that the oil level is correct. Check the crankcase
for leakage.P3-12~14
Gear shifter and clutch Check that gears can be shifted correctly in order and
that the clutch operates smoothly.P3-9
Throttle grip/Housing Check that the throttle grip operation and free play
are correctly adjusted. Lubricate the throttle grip and  P3-10~11
housing, if necessary.
Brakes Check the play of front brake and effect of front and
rear brake.P3-17~23
Chain Check chain slack and alignment. Check that the chain
is lubricated properly.P3-24~26
Wheels Check for excessive wear and tire pressure. Check for
loose spokes and have no excessive play.P3-34~35
Steering Check that the handlebar can be turned smoothly and
have no excessive play.P3-35~36
Front forks and  Check that they operate smoothly and there is no oil
rear shock absorber leakage.P3-26~33
Cables (wires) Check that the clutch and throttle cables move smooth-
ly. 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.P3-15~16
Sprocket Check that the driven sprocket tightening bolt is
not loose.P3-24
Lubrication Check for smooth operation. Lubricate if necessary. P3-37
Bolts and nuts Check the chassis and engine for loose bolts and nuts. P1-16
Lead connectors Check that the CDI magneto, CDI unit, and ignition coil
are connected tightly.P1-6
Settings Is the machine set suitably for the condition of the
racing course and weather or by taking into account the
P7-1~24
results of test runs before racing? Are inspection and
maintenance completely done?
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INSP
ADJ
3-5
ENGINE/COOLANT LEVEL INSPECTION/
COOLANT REPLACEMENT
EC350000
ENGINE
EC351011
COOLANT LEVEL INSPECTION
w
Do not remove the radiator cap 1 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.
cC
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. Remove:
9Radiator cap
3. Check:
9Coolant level a
Coolant level lowAdd coolant.
1Radiator
EC353011
COOLANT REPLACEMENT
w
Do not remove the radiator cap when the
engine is hot.
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INSP
ADJ
3-6
COOLANT REPLACEMENT
cC
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:
9Coolant drain bolt 1
3. Remove:
9Radiator cap
Drain the coolant completely.
4. Clean:
9Cooling system
Thoroughly flush the cooling system with
clean tap water.
5. Install:
9Copper washer
9Coolant drain bolt
6. Fill:
9Radiator
9Engine
To specified level.
Recommended coolant:
High quality ethylene glycol
anti-freeze containing
anti-corrosion for
aluminum engine
Coolant 1and water
(soft water) 2mixing ratio:
50%/50%
Coolant capacity:
1.20 L (1.06 Imp qt, 1.27 US qt)
10 Nm (1.0 m•kg, 7.2 ft•lb)
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INSP
ADJ
3-7
RADIATOR CAP INSPECTION
cC
9
Do not mix more than one type of ethyl-
ene glycol antifreeze containing corro-
sion inhibitors for aluminum engine.
9Do not use water containing impurities
or oil.
7. Install:
9Radiator cap
Start the engine and warm it up for a sev-
eral minutes.
8. Check:
9Coolant level
Coolant level lowAdd coolant.
EC355000
RADIATOR CAP INSPECTION
1. Inspect:
9Seal (radiator cap) 1
9Valve and valve seat 2
Crack/DamageReplace.
Exist fur deposits 3Clean or replace.
Handling notes of coolant:
The coolant is harmful so it should be handled
with special care.
w
9
When coolant splashes to your eye.
Thoroughly wash your eye with water
and see your doctor.
9When coolant splashes to your clothes.
Quickly wash it away with water and then
with soap.
9When coolant is swallowed.
Quickly make him vomit and take him to
a doctor.
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