2002 YAMAHA YZ250LC radiator

CHAPTER 4
ENGINE
SEAT, FUEL TANK AND SIDE
COVERS.....................................................4-1
EXHAUST PIPE AND SILENCER..............4-3
RADIATOR..................................................4-4
CARBURETOR AND REED VALVE...........4-7
CYLINDER HEAD , CYLINDER AND
PISTON.....................................................4-18
CLUTCH AND PRIMARY DRIVEN
GEAR.......................................................4-33
KICK AXLE, SHIFT SHAFT AND
PRIMARY DRIVE GEAR...........................4-40
YPVS GOVERNOR...................................4-49
WATER PUMP..........................................4-52
CDI MAGNETO.........................................4-56
ENGINE REMOVAL..................................4-60
CRANKCASE AND CRANKSHAFT.........4-65
TRANSMISSION, SHIFT CAM AND
SHIFT FORK.............................................4-72
CHAPTER 5
CHASSIS
FRONT WHEEL AND REAR WHEEL........5-1
FRONT BRAKE AND REAR BRAKE.......5-10
FRONT FORK...........................................5-27
HANDLEBAR............................................5-40
STEERING................................................5-47
SWINGARM..............................................5-52
REAR SHOCK ABSORBER.....................5-59
5NX-9-30-0 6/5/01 3:49 PM Page 20

KAPITEL 4
MOTOR
SITZ, KRAFTSTOFFTANK UND
SEITENDECKEL.........................................4-1
AUSPUFFROHR UND
SCHALLDÄMPFER....................................4-3
KÜHLER......................................................4-4
VERGASER UND ZUNGENVENTIL...........4-7
ZYLINDERKOPF, ZYLINDER UND
KOLBEN...................................................4-18
KUPPLUNG UND
PRIMÄRABTRIEBSZAHNRAD................4-33
KICKSTARTERWELLE, SCHALTWELLE
UND PRIMÄRANTRIEBSZAHNRAD.......4-40
YPVS REGLER.........................................4-49
WASSERPUMPE......................................4-52
CDI-MAGNETZÜNDER.............................4-56
AUSBAU DES MOTORS..........................4-60
KURBELGEHÄUSE UND
KURBELWELLE.......................................4-65
GETRIEBE, SCHALTNOCKE UND
SCHALTGABEL.......................................4-72
KAPITEL 5
FAHRGESTELL
VORDERRAD UND HINTERRAD..............5-1
VORDERRADBREMSE UND
HINTERRADBREMSE..............................5-10
VORDERRADGABEL...............................5-27
LENKSTANGE..........................................5-40
LENKUNG.................................................5-47
HINTERRADSCHWINGE..........................5-52
HINTERRAD-STOSSDÄMPFER..............5-59
CHAPITRE 4
MOTEUR
SELLE, RESERVOIR A ESSENCE
ET COUVERCLES LATERAUX..............4-1
TUYAU D’ECHAPPEMENT ET
SILENCIEUX..............................................4-3
RADIATEUR...............................................4-4
CARBURATEUR ET
SOUPAPE FLEXIBLE...............................4-7
CULASSE, CYLINDRE ET PISTON.....4-18
EMBRAYAGE ET PIGNON
MENE PRIMAIRE....................................4-33
AXE DE DEMARREUR AU PIED,
ARBRE DE SELECTEUR ET PIGNON
DE TRANSMISSION PRIMAIRE..........4-40
REGULATEUR YPVS..............................4-49
POMPE A EAU.........................................4-52
MAGNETO CDI........................................4-56
DEPOSE DU MOTEUR...........................4-60
CARTER ET VILEBREQUIN.................4-65
BOITE A VITESSES, BARILLET
DE SELECTEUR ET FOURCHETTE...4-72
CHAPITRE 5
PARTIE CYCLE
ROUE AVANT ET ROUE ARRIERE......5-1
FREIN AVANT ET FREIN ARRIERE..5-10
FOURCHE AVANT..................................5-27
GUIDON.....................................................5-40
DIRECTION..............................................5-47
BRAS OSCILLANT..................................5-52
AMORTISSEUR ARRIERE....................5-59
CAPITOLO 4
MOTORE
SELLA, SERBATOIO DEL
CARBURANTE E COPERTURE
LATERALI..................................................4-1
TUBO DI SCARICO E
SILENZIATORE.........................................4-3
RADIATORE...............................................4-4
CARBURATORE E VALVOLA A
LAMELLA...................................................4-7
TESTA CILINDRO, CILINDRO E
PISTONE....................................................4-18
FRIZIONE E INGRANAGGIO
CONDOTTO PRIMARIO........................4-33
PEDIVELLA, ALBERO DEL
CAMBIO E INGRANAGGIO
CONDUTTORE PRIMARIO...................4-40
REGOLATORE YPVS.............................4-49
POMPA DELL’ACQUA...........................4-52
MAGNETE CDI........................................4-56
RIMOZIONE DEL MOTORE.................4-60
CARTER E ALBERO A GOMITI..........4-65
TRASMISSIONE, CAMMA DEL
CAMBIO E FORCELLA DEL
CAMBIO....................................................4-72
CAPITOLO 5
TELAIO
RUOTA ANTERIORE E RUOTA
POSTERIORE.............................................5-1
FRENO ANTERIORE E FRENO
POSTERIORE ..........................................5-10
FORCELLA ANTERIORE......................5-27
MANUBRIO...............................................5-40
STERZO.....................................................5-47
FORCELLONE OSCILLANTE..............5-52
AMMORTIZZATORE POSTERIORE..5-59
5NX-9-30-0 6/5/01 3:49 PM Page 21

1-1
DESCRIPTION
GEN
INFO
EC100000
GENERAL INFORMATION
EC110000
DESCRIPTION
1Clutch lever
2“ENGINE STOP” button
3Front brake lever
4Throttle grip
5Radiator cap
6Fuel tank cap
7Kick starter
8Fuel tank
9Radiator
0Coolant drain bolt
qCheck bolt (Transmission oil level)
wRear brake pedal
eValve joint
rFuel cock
tStarter knob
yDrive chain
uAir cleaner
iShift pedal
oFront fork
NOTE:
9The machine you have purchased may differ
slightly from those shown in the following.
9Designs and specifications are subject to
change without notice.
1
5NX-9-30-1 6/5/01 3:53 PM Page 2

1-1
DESCRIPTION
BESCHREIBUNG
DESCRIZIONE
GEN
INFO
ALLGEMEIN
ANGABEN
BESCHREIBUNG1Kupplungshebel
2Motorstoppknopf „ENGINE STOP“
3Handbremshebel
4Gasdrehgriff
5Kühlerdeckel
6Kraftstofftank-Verschluß
7Kickstarter
8Kraftstofftank
9Kühler
0Kühlmittel-Ablaßschraube
qPrüfschraube (Getriebeölstand)
wFußbremshebel
eVentilverbindung
rKraftstoffhahn
tStarterknopf
yAntriebskette
uLuftfilter
iSchalthebel
oVorderradgabel
HINWEIS:
9Die von Ihnen gekaufte Maschine
könnte etwas von den hier gezeigten
Abbildungen abweichen.
9Anderungen des Designs und der
Technischen Daten ohne vorherge-
hende Bekanntgage vorbehalten.
RENSEIGNEMENTS
GENERAUX
DESCRIPTION1Levier d’embrayage
2Bouton de coupe-circuit de sécurité
“ENGINE STOP”
3Levier de frein avant
4Poignée d’accélérateur
5Bouchon du radiateur
6Bouchon de réservoir à essence
7Kickstarter
8Réservoir de carburant
9Radiateur
0Boulon de vidange du liquide de
refroidissement
qBoulon de contrôle
(niveau d’huile de transmission)
wPédale de frein arrière
eJoint de robinet
rRobinet à essence
tBouton de starter
yChaîne de transmission
uFiltre à air
iPédale de sélecteur
oFourche avant
N.B.:
9La machine que vous avez achetée
diffère peutêtre partiellement de celles
montrées sur ces photos.
9La conception et les caractéristiques
peuvent êtres changées sans préavis.
IC100000
INFORMAZIONI
GENERALI
IC110000
DESCRIZIONE
1Leva di comando della frizione
2Pulsante “ARRESTO MOTORE”
3Leva di comando del freno anteriore
4Manopola dell’acceleratore
5Tappo del radiatore
6Tappo del serbatoio del carburante
7Pedivella della messa in moto
8Serbatoio del carburante
9Radiatore
0Bullone di drenaggio del liquido
refrigerante
qBullone di controllo
(livello dell’olio della trasmissione)
wPedale di comando del freno posteriore
eGiunto della valvola
rRubinetto del carburante
tManopola dell’avviamento
yCatena di trasmissione
uFiltro dell’aria
iPedale del cambio
oForcella anteriore
NOTA:
9Il veicolo acquistato può essere leg-
germente diverso da quelli illustrati
qui sotto.
9Progetti e specifiche sono soggetti a
variazioni senza preavviso.
1
5NX-9-30-1 6/5/01 3:53 PM Page 3

1-7
SPECIAL TOOLS
GEN
INFO
EC140002
SPECIAL TOOLS
The proper special tools are necessary for complete and accurate tune-up and assembly. Using the
correct special tool will help prevent damage caused by the use of improper tools or improvised tech-
niques. The shape and part number used for the special tool differ by country, so two types are provid-
ed. Refer to the list provided to avoid errors when placing an order.
NOTE:
9For U.S.A. and Canada, use part number starting with “YM-”, “YU-” or “ACC -”.
9For others, use part number starting with “90890-”.
Part number Tool name / How to use IIIustration
YU-1135-A, 90890-01135Crankcase separating toolYU-1135-A 90890-01135
This tool is used to split the crankcase as well
as remove the crankshaft from either case.
YM-1189, 90890-01189 Flywheel puller
YM-1189 90890-01189
This tool is used to remove the flywheel magneto.
YU-1235, 90890-01235 Rotor holding tool
YU-1235 90890-01235
This tool is used when loosening or tightening the
flywheel magneto securing nut.
YU-3097, 90890-01252 Dial gauge and stand
YU-3097 90890-01252
YU-1256 Spark plug hole dial standYU-1256
These tools are used to set the ignition timing.
Crankcase installing tool
YU-90050 90890-01274
YU-90050, 90890-01274 PotYM-1277 90890-01275
YU-90050, 90890-01275 Bolt90890-01277
YM-1277, 90890-01277 Adapter
These tools are used to install the crankshaft.
YU-1304, 90890-01304 Piston pin puller
YU-1304 90890-01304
This tool is used to remove the piston pin.
YU-24460-01,90890-01325Radiator cap testerYU-24460-01 90890-01325
YU-33984, 90890-01352 AdapterYU-33984 90890-01352
These tools are used for checking the cooling
system.
5NX-9-30-1 6/5/01 3:53 PM Page 14

1-7
UTENSILI SPECIALI
GEN
INFO
IC140002
UTENSILI SPECIALI
Per una messa a punto e un montaggio completi e accurati sono necessari gli utensili speciali adeguati.
L’uso dell'utensile speciale corretto contribuirà a evitare danni provocati dall’uso di utensili impropri o di
tecniche improvvisate. La forma e il numero categorico usati per l’utensile speciale sono diversi a seconda
del paese, quindi vengono forniti due tipi. Consultare la lista fornita per evitare errori quando si piazza un
ordine.
NOTA:
9Per Stati Uniti e Canada, usare il numero categorico che inizia con “YM”, “YU” o “ACC”.
9Per gli altri, usare il numero categorico che inizia per “90890-”.
Numero categorico Nome dell’utensile / Come usarlo Illustrazione
YU-1135-A, 90890-01135 Utensile per separare il carter
Oltre che a separare il carter, questo strumento serve a
togliere l’albero a gomiti da una delle due parti del car-
ter.YU-1135-A 90890-01135
YM-1189, 90890-01189 Estrattore del volano
Questo utensile viene usato per togliere il magnete del
volano.YM-1189 90890-01189
YU-1235, 90890-01235 Utensile di supporto del rotore
Quepsile viene usato quando si allenta o si serra il dado
di fissaggio del magnete del volano.YU-1235 90890-01235
YU-3097, 90890-01252
YU-1256Comparatore e supporto
Supporto del comparatore del foro della candela
Questi utensili vengono usati per regolare la messa in
fase dell'ac.YU-3097
YU-125690890-01252
YU-90050, 90890-01274
YU-90050, 90890-01275
YM-1277, 90890-01277Utensile per l’installazione del carter
Recipiente
Bullone
Adattatore
Questi utensili vengono usati per installare l’albero a gomiti.
YU-90050
YM-127790890-01274
90890-01275
90890-01277
YU-1304, 90890-01304 Estrattore dello spinotto
Questo utensile viene usato per togliere lo spinotto.YU-1304 90890-01304
YU-24460-01, 90890-01325
YU-33984, 90890-01352Tester del tappo del radiatore
Adattatore
Questi utensili vengono usati per controllare l’impianto
di raffreddamento.
YU-24460-01
YU-3398490890-01325
90890-01352
5NX-9-30-1 6/5/01 3:53 PM Page 20

2-4
MAINTENANCE SPECIFICATIONSSPEC
Item Standard Limit
Transmission:
Main axle deflection limit…
0.01 mm (0.0004 in)
Drive axle deflection limit…
0.01 mm (0.0004 in)
Shifter:
Shifting type Cam drum and guide bar…
Guide bar bending limit…
0.05 mm (0.0020 in)
Kick starter type: Kick and ratchet type…
Air filter oil grade (oiled filter):Foam-air-filter oil or engine mixing oil…
Carburetor:USA, CDN, ZA,
EUROPE
AUS, NZ
Type/Manufacturer
PWK38S/KEIHIN←…
I.D. mark 5NX1 00 5NX2 10…
Main jet (M.J.) #178 #175…
Main air jet (M.A.J) #200←…
Jet needle-clip position (J.N.) N3EJ-2 N3CW-3…
Main nozzle (N.J.) ø2.9←…
Cutaway (C.A.) #7←…
Pilot jet (P.J.) #50 #52…
Pilot air screw (P.A.S.) 1 1-3/8…
(for reference only)
Valve seat size (V.S.)
ø3.8 mm (0.15 in)←…
Starter jet (G.S.) #85←…
Power jet (P.W.J.) #50←…
Float arm height (F.H.) 5.5~7.5 mm←…
(0.22~030 in)
Reed valve:
Thickness* 0.42 mm (0.017 in)…
Valve stopper height 10.3~10.7 mm (0.406~0.421 in)…
Valve bending limit…
0.2 mm (0.008 in)
Cooling:
Radiator core size:
Width 107.8 mm (4.24 in)…
Height 240 mm (9.45 in)…
Thickness 32 mm (1.26 in)…
Radiator cap opening pressure 95~125 kPa…
(0.95~1.25 kg/cm
2, 13.5~17.8 psi)
Radiator capacity (total) 0.63 L (0.55 Imp qt, 0.67 US qt)…
Water pump:
Type Single-suction centrifugal pump…
5NX-9-30-2 6/7/01 1:57 PM Page 5

2-5
MAINTENANCE SPECIFICATIONSSPEC
Part to be tightened Thread size Q’tyT ightening torqueNm m•kg ft•lb
Spark plug M14 ×1.25 1 20 2.0 14
Cylinder head (nut) M 8 ×1.25 6 25 2.5 18
(stud) M 8 ×1.25 6 13 1.3 9.4
Cylinder (nut) M10 ×1.25 4 35 3.5 25
(stud) M10 ×1.25 4 13 1.3 9.4
Power valve :
Holder M 5 ×0.8 2 6 0.6 4.3
Link rod M 5 ×0.8 2 6 0.6 4.3
Push rod M 5 ×0.8 1 5 0.5 3.6
Thrust plate M 5 ×0.8 1 6 0.6 4.3
Side holder M 5 ×0.8 4 4 0.4 2.9
Link lever M 4 ×0.7 1 4 0.4 2.9
Pulley M 4 ×0.7 2 4 0.4 2.9
Cover M 5 ×0.8 4 4 0.4 2.9
Governor fork M 4 ×0.7 2 5 0.5 3.6
Housing M 5 ×0.8 4 5 0.5 3.6
Impeller M 8 ×1.25 1 14 1.4 10
Water pump housing cover M 6 ×1.0 4 10 1.0 7.2
Coolant drain bolt M 6 ×1.0 1 10 1.0 7.2
Radiator M 6 ×1.0 6 10 1.0 7.2
Radiator panel M 6 ×1.0 2 10 1.0 7.2
Radiator hose clamp M 6 ×1.0 8 1 0.1 0.7
Air filter element M 6 ×1.0 1 2 0.2 1.4
Carburetor joint M 6 ×1.0 5 10 1.0 7.2
Air filter case M 6 ×1.0 4 8 0.8 5.8
Air filter guide clamp M 5 ×0.8 1 1 0.1 0.7
Reed valve M 3 ×0.5 4 1 0.1 0.7
Exhaust pipe (front) M 6 ×1.0 1 14 1.4 10
Exhaust pipe (rear) M 6 ×1.0 1 12 1.2 8.7
Exhaust pipe stay (front) M 8 ×1.25 1 25 2.5 18
Exhaust pipe stay (rear) M 6 ×1.0 1 12 1.2 8.7
Silencer (front) M 6 ×1.0 1 12 1.2 8.7
Silencer (rear) M 6 ×1.0 1 7 0.7 5.1
Fiber (silencer) M 6 ×1.0 2 10 1.0 7.2
Crankcase M 6 ×1.0 11 14 1.4 10
Crankcase cover (left) M 6 ×1.0 5 8 0.8 5.8
Chain cover M 6 ×1.0 2 8 0.8 5.8
Crankcase cover (right) M 6 ×1.0 9 10 1.0 7.2
Bearing plate cover (drive axle left) M 6 ×1.0 2 10 1.0 7.2
Bearing plate cover (main axle right) M 6 ×1.0 2 10 1.0 7.2
Holder M 6 ×1.0 2 10 1.0 7.2
Oil drain bolt M12 ×1.5 1 20 2.0 14
Oil check bolt M 6 ×1.0 1 10 1.0 7.2
Kick starter M 8 ×1.25 1 30 3.0 22
Ratchet wheel stopper M 6 ×1.0 2 10 1.0 7.2
Clutch cover M 6 ×1.0 6 10 1.0 7.2
5NX-9-30-2 6/7/01 1:57 PM Page 6