2002 YAMAHA WR 250F magneto

CHAPTER 4
ENGINE
SEAT, FUEL TANK
AND SIDE COVERS
................................. 4-1
EXHAUST PIPE AND SILENCER
............ 4-2
RADIATOR
................................................ 4-4
CARBURETOR
......................................... 4-7
CAMSHAFTS
.......................................... 4-21
CYLINDER HEAD
................................... 4-30
VALVES AND VALVE SPRINGS
........... 4-34
CYLINDER AND PISTON
....................... 4-43
CLUTCH
.................................................. 4-50
OIL FILTER ELEMENT, WATER PUMP
AND RIGHT CRANKCASE COVER
...... 4-57
BALANCER
............................................ 4-64
OIL PUMP
............................................... 4-67
KICK SHAFT AND SHIFT SHAFT
.......... 4-72
CDI MAGNETO
....................................... 4-79
ENGINE REMOVAL
................................ 4-83
CRANKCASE AND CRANKSHAFT
....... 4-88
TRANSMISSION, SHIFT CAM
AND SHIFT FORK
.................................. 4-97
CHAPTER 5
CHASSIS
FRONT WHEEL AND REAR WHEEL
...... 5-1
FRONT BRAKE AND REAR BRAKE
..... 5-11
FRONT FORK
......................................... 5-28
HANDLEBAR
.......................................... 5-41
STEERING
.............................................. 5-47
SWINGARM
............................................ 5-53
REAR SHOCK ABSORBER
................... 5-60

GEN
INFO
1 - 7
SPECIAL TOOLS
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
techniques. The shape and part number used for the special tool differ by country, so two types are
provided. Refer to the list provided to avoid errors when placing an order.
NOTE:
For U.S.A. and Canada, use part number starting with “YM-”, “YU-” or “ACC-”.
For others, use part number starting with “90890-”.
Part number Tool name/How to use Illustration
YU-1135-A, 90890-01135 Crankcase separating tool
These tool is used to remove the crankshaft from
either case.YU-1135-A 90890-01135
YU-1235, 90890-01235 Rotor holding tool
This tool is used when loosening or tightening the fly-
wheel magneto securing nut.YU-1235 90890-01235
YU-3097, 90890-01252
YU-1256Dial gauge and stand
Stand
These tools are used to check each part for runout or
bent.YU-3097
YU-125690890-01252
YU-90050, 90890-01274
YU-90050, 90890-01275
YU-91044, 90890-04081
YM-1277, 90890-01277Crankshaft installing tool
Crankshaft installing pot
Crankshaft installing bolt
Spacer (crankshaft installer)
Adapter (M10)
These tools are used to install the crankshaft.YU-90050
YM-1277
YU-9104490890-01274
90890-01275
90890-01277
90890-04081
YU-1304, 90890-01304 Piston pin puller set
This tool is used to remove the piston pin.YU-1304 90890-01304
YU-24460-01, 90890-01325
YU-33984, 90890-01352Radiator cap tester
Radiator cap tester adapter
These tools are used for checking the cooling sys-
tem.YU-24460-01
YU-3398490890-01325
90890-01352
YU-33270-B, 90890-01362Flywheel puller
This tool is used to remove the flywheel magneto.YM-33270-B 90890-01362

SPEC

2 - 3
GENERAL SPECIFICATIONS
Tire:
Type With tube
Size (front) 80/100-21 51M (For USA, CDN and ZA)
90/90-21 54R (For EUROPE, AUS and NZ)
Size (rear) 100/100-18 59M (For USA, CDN and ZA)
130/90-18 69R (For EUROPE, AUS and NZ)
Tire pressure (front and rear) 100 kPa (1.0 kgf/cm
2

, 15 psi)
Brake:
Front brake type Single disc brake
Operation Right hand operation
Rear brake type Single disc brake
Operation Right foot operation
Suspension:
Front suspension Telescopic fork
Rear suspension Swingarm (link type monocross suspension)
Shock absorber:
Front shock absorber Coil spring/oil damper
Rear shock absorber Coil spring/gas, oil damper
Wheel travel:
Front wheel travel 300 mm (11.8 in)
Rear wheel travel 315 mm (12.4 in)
Electrical:
Ignition system CDI magneto
Headlight type: Quartz bulb (halogen)
Bulb wattage
×
quantity:
Headlight 12 V 60/55 W
×
1
Taillight 12 V 21/5 W
×
1

SPEC
2 - 17
MAINTENANCE SPECIFICATIONS
EC212300
ELECTRICAL
Item Standard Limit
Ignition system:
Advancer type Electrical ----
CDI:
Magneto-model (stator)/manufac-
turer5NG-50/YAMAHA----
Charging coil 1 resistance (color) 640 ~ 960 Ω at 20 ˚C (68 ˚F)
(Green – Brown)----
Charging coil 2 resistance (color) 464 ~ 696 Ω at 20 ˚C (68 ˚F)
(Green – Pink)----
Lighting coil resistance (color) 0.16 ~ 0.24 Ω at 20 ˚C (68 ˚F)
(Black – Yellow)----
Pickup coil resistance (color) 248 ~ 372 Ω at 20 ˚C (68 ˚F)
(White – Red)----
CDI unit-model/manufacturer 5PH-50/YAMAHA
(For USA)
5PH-60/YAMAHA
(For EUROPE)
5PH-80/YAMAHA
(For CDN, AUS, NZ and ZA)----
----
----
Ignition coil:
Model/manufacturer 4SR-00/YAMAHA ----
Minimum spark gap 6 mm (0.24 in) ----
Primary coil resistance 0.20 ~ 0.30 Ω at 20 ˚C (68 ˚F) ----
Secondary coil resistance 9.5 ~ 14.3 kΩ at 20 ˚C (68 ˚F) ----
Part to be tightened Thread size Q’tyTightening torque
Nm m·kg ft·lb
Stator M6 × 1.0 3 10 1.0 7.2
Rotor M10 × 1.25 1 48 4.8 35
Neutral switch M5 × 0.8 2 4 0.4 2.9
Ignition coil M6 × 1.0 2 7 0.7 5.1

2 - 3
SPEC

Pneu:
Type de pneu Avec chambre à air
Taille de pneu (avant) 80/100-21 51M (USA, CDN et ZA)
90/90-21 54R (EUROPE, AUS et NZ)
Taille de pneu (arrière) 100/100-18 59M (USA, CDN et ZA)
130/90-18 69R (EUROPE, AUS et NZ)
Pression de pneu (avant et arrière) 100 kPa (1,0 kgf/cm
2

, 15 psi)
Freins:
Type de frein avant Monodisque
Commande Main droite
Type de frein arrière Monodisque
Commande Pied droit
Suspension:
Suspension avant Fourche télescopique
Suspension arrière Bras oscillant (monocross de type biellette)
Amortisseurs:
Amortisseur avant Ressort hélicoïdal/amortisseur hydraulique
Amortisseur arrière Ressort hélicoïdal/amortisseur hydro-pneumatique
Débattement:
Roue avant 300 mm (11,8 in)
Roue arrière 315 mm (12,4 in)
Partie électrique:
Système d’allumage Magnéto CDI
Type de phare: Ampoule de quartz (halogène)
Puissance de l’ampoule
×
quantité:
Phare 12 V 60/55 W
×
1
Feu arrière 12 V 21/5 W
×
1
CARACTERISTIQUES GENERALES

2 - 17
SPEC
PARTIE ELECTRIQUE
Article Standard Limite
Système d’allumage:
Type de dispositif d’avance Electrique ----
CDI:
Modèle/fabricant de la magnéto (stator) 5NG-50/YAMAHA ----
Résistance de bobine de charge 1
(couleur)640 à 960 Ω à 20 ˚C (68 ˚F)
(vert – brun)----
Résistance de bobines de charge 2
(couleur)464 à 696 Ω à 20 ˚C (68 ˚F)
(vert – rose)----
Résistance de la bobine d’éclairage
(couleur)0,16 à 0,24 Ω à 20 ˚C (68 ˚F)
(noir – jaune)----
Résistance de bobine d’excitation
(couleur)248 à 372 Ω à 20 ˚C (68 ˚F)
(blanc – rouge)----
Modèle/fabricant du bloc CDI 5PH-50/YAMAHA
(USA)
5PH-60/YAMAHA
(EUROPE)
5PH-80/YAMAHA
(CDN, AUS, NZ et ZA)----
----
----
Bobine d’allumage:
Modèle/fabricant 4SR-00/YAMAHA ----
Longueur minimum d’étincelle 6 mm (0,24 in) ----
Résistance de l’enroulement primaire 0,20 à 0,30 Ω à 20 ˚C (68 ˚F) ----
Résistance de l’enroulement secondaire 9,5 à 14,3 kΩ à 20 ˚C (68 ˚F) ----
Pièce à serrerTaille de
filetageQtéCouple de serrage
Nm m·kg ft·lb
Stator M6 × 1,0 3 10 1,0 7,2
Rotor M10 × 1,25 1 48 4,8 35
Contacteur de point mort M5 × 0,8 2 4 0,4 2,9
Bobine d’allumage M6 × 1,0 2 7 0,7 5,1
CARACTERISTIQUES D’ENTRETIEN

SPEC

2 - 3
SPECIFICHE GENERALI
Pneumatici:
Tipo Con camera d’aria
Dimensioni (anteriore) 80/100-21 51M (Per USA, CDN e ZA)
90/90-21 54R (Per l’EUROPA, AUS e NZ)
Dimensioni (posteriore) 100/100-18 59M (Per USA, CDN e ZA)
130/90-18 69R (Per l’EUROPA, AUS e NZ)
Pressione pneumatici (anteriore e posteriore) 100 kPa (1,0 kgf/cm
2

, 15 psi)
Freno:
Tipo freno anteriore Freno a disco singolo
Azionamento Con la mano destra
Tipo freno posteriore Freno a disco singolo
Azionamento Con il piede destro
Sospensione:
Sospensione anteriore Forcella telescopica
Sospensione posteriore Forcellone oscillante (sospensione monocross di tipo
a biscottino)
Ammortizzatore:
Ammortizzatore anteriore Molla elicoidale/ammortizzatore a olio
Ammortizzatore posteriore Ammortizzatore a molla elicoidale/a gas
Corsa della ruota:
Corsa ruota anteriore 300 mm (11,8 in)
Corsa ruota posteriore 315 mm (12,4 in)
Parte elettrica:
Impianto di accensione Magneto CDI
Tipo di faro: Lampada al quarzo (alogena)
Wattaggio
×
quantità lampade:
Faro 12V 60/55 W
×
1
Fanalino posteriore 12V 21/5 W
×
1

SPEC
2 - 17
SPECIFICHE DI MANUTENZIONE
PARTE ELETTRICA
Elemento Standard Limite
Impianto di accensione:
Tipo di dispositivo di anticipo Elettrico ----
CDI.:
Modello/costruttore magneto (statore) 5NG-50/YAMAHA----
Resistenza bobina di carica 1 (colore) 640 ~ 960 Ω a 20 ˚C (68 ˚F)
(Verde – Marrone)----
Resistenza bobina di carica 2 (colore) 464 ~ 696 Ω a 20 ˚C (68 ˚F)
(Verde – Rosa)----
Resistenza della bobina illuminazione
(colore)0,16 ~ 0,24 Ω a 20 ˚C (68 ˚F)
(Nero – Giallo)----
Resistenza bobina pickup (colore) 248 ~ 372 Ω a 20 ˚C (68 ˚F)
(Bianco – Rosso)----
Modello/costruttore unità CDI 5PH-50/YAMAHA
(Per USA)
5PH-60/YAMAHA
(Per l’EUROPE)
5PH-80/YAMAHA
(Per CDN, AUS, NZ e ZA)----
----
----
Bobina di accensione:
Modello/costruttore 4SR-00/YAMAHA ----
Distanza minima scintilla 6 mm (0,24 in) ----
Resistenza avvolgimento primario 0,20 ~ 0,30 Ω a 20 ˚C (68 ˚F) ----
Resistenza avvolgimento secondario 9,5 ~ 14,3 kΩ a 20 ˚C (68 ˚F) ----
Elemento da serrareDimensioni
della
filettaturaQuantitàCoppia di serraggio
Nm m·kg ft·lb
Statore M6 × 1,0 3 10 1,0 7,2
Rotore M10 × 1,25 1 48 4,8 35
Interruttore folle M5 × 0,8 2 4 0,4 2,9
Bobina di accensione M6 × 1,0 2 7 0,7 5,1