2002 YAMAHA WR 250F magneto

4 - 80
ENGCDI MAGNETO
EC4L3000
REMOVAL POINTS
Rotor
1. Remove:
Nut (rotor) 1
Washer 2
Use the rotor holding tool 3.
2. Remove:
Rotor 1
Use the flywheel puller 2.
NOTE:
Install three bolts 3 of the proper size, as
shown in illustration.
Rotor holding tool:
YU-1235/90890-01235
Flywheel puller:
YU-33270-B/90890-01362
EC4L4000
INSPECTION
EC4L4101
CDI magneto
1. Inspect:
Rotor inner surface a
Stator outer surface b
Damage → Inspect the crankshaft
runout and crankshaft bearing.
If necessary, replace CDI magneto and/
or stator.
EC4L4200
Woodruff key
1. Inspect:
Woodruff key 1
Damage → Replace.

4 - 81
ENGCDI MAGNETO
EC4L5000
ASSEMBLY AND INSTALLATION
CDI magneto
1. Install:
Stator 1
Screw (stator) 2
NOTE:
Apply the sealant on the grommet of the CDI
magneto lead.
Tighten the screws using the T30 bit.
Quick gasket®:
ACC-QUICK-GS-KT
YAMAHA Bond No. 1215:
90890-85505
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
2. Install:
Woodruff key 1
Rotor 2
NOTE:
Clean the tapered portions of the crankshaft
and rotor.
When installing the woodruff key, make sure
that its flat surface a is in parallel with the
crankshaft center line b.
When installing the rotor, align the keyway c
of the rotor with the woodruff key.
3. Install:
Washer 1
Nut (rotor) 2
Use the rotor holding tool 3.
Rotor holding tool:
YU-1235/90890-01235
T R..48 Nm (4.8 m · kg, 35 ft · lb)

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ENGCDI MAGNETO
4. Connect:
CDI magneto lead
Refer to “CABLE ROUTING DIA-
GRAM” section in the CHAPTER 2.
5. Install:
Dowel pin
Gasket (left crankcase cover)
Left crankcase cover 1
Hose guide (cylinder head breather
hose) 2
Bolt (left crankcase cover) 3
NOTE:
Tighten the bolts in stage, using a crisscross
pattern.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
6. Install:
Left engine guard 1
Hose holder (cylinder head breather
hose) 2
Bolt (left engine guard) 3
Cylinder head breather hose 4
3
2
14
3
T R..23 Nm (2.3 m · kg, 17 ft · lb)

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ENGENGINE REMOVAL
Extent of removal:1 Engine removal
Extent of removal Order Part name Q’ty Remarks
Spark plug cap
Disconnect the CDI magneto lead.
Right engine guard
1 Neutral switch 1
2 Bolt (oil hose) 2
3 Drive chain sprocket cover 1
4 Nut (drive sprocket) 1
Refer to “REMOVAL POINTS”. 5 Lock washer 1
6 Drive sprocket 1
7 Clip 1
8 Bolt (brake pedal) 1
9 Brake pedal 1
10 Upper engine bracket 2
11 Lower engine bracket 2
12 Engine mounting bolt 3
13 Pivot shaft 1
Refer to “REMOVAL POINTS”.
14Engine
1
1

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ENGCRANKCASE AND CRANKSHAFT
CRANKCASE AND CRANKSHAFT
Extent of removal:1 Crankcase separation2 Crankshaft removal
Extent of removal Order Part name Q’ty Remarks
CRANKCASE AND CRANK-
SHAFT REMOVAL
Preparation for removal Engine Refer to “ENGINE REMOVAL” section.
Piston Refer to “CYLINDER AND PISTON” sec-
tion.
Kick shaft assembly
Refer to “KICK SHAFT AND SHIFT
SHAFT” section.
Segment
Stator Refer to “CDI MAGNETO” section.
Balancer shaft Refer to “BALANCER” section.
1 Timing chain guide (intake side) 1
2 Timing chain 1
3Oil delivery pipe 2
1
21

6 - 1
–+ELEC

ELECTRICAL COMPONENTS AND WIRING DIAGRAM
EC600000
ELECTRICAL
EC610000
ELECTRICAL COMPONENTS AND WIRING DIAGRAM
EC611000
ELECTRICAL COMPONENTS
1
Headlight
2
Voltage regulator
3
Engine stop switch
4
Throttle position sensor
5
Taillight
6
Neutral switch
7
CDI magneto
8
Spark plug
9
Ignition coil
0
Light switch
A
CDI unit
COLOR CODE
B...................... Black
Br .................... Brown
G ..................... Green
Gy ................... Gray
L ...................... Blue
O ..................... Orange
P...................... Pink
R ..................... Red
Sb.................... Sky blue
EC612000
WIRING DIAGRAM
B/L
R/WL/W
LY
L
Y
B
1B L
YYLB
5LB
YBLB
LB
2
6
4 9
8
W
R Br
G PB/YP
B Br
G W
R
O
L Y B/LSbSb
B/L Y O
L
A
Y
Br
Gy
PGR
WB
L YL Y
B B/L
SbW
Sb
WL/W
R/WL/WSbR/WSb
W
O
B
0
7
BGyBGy
Y
BL
B
B
3B/WBB/WG/B
L
B YLB Y

W ..................... White
Y ...................... Yellow
B/L ................... Black/Blue
B/W .................. Black/White
B/Y ................... Black/Yellow
G/B................... Green/Black
L/W .................. Blue/White
R/W .................. Red/White

–+ELEC

COMPOSANTS ELECTRIQUES ET SCHEMA DE CABLAGE
ELEKTRISCHE BAUTEILE UND SCHALTPLAN
COMPONENTI ELETTRICI E SCHEMA DI CABLAGGIO
ELEKTRISCHE
ANLAGE
ELEKTRISCHE BAUTEI-
LE UND SCHALTPLAN
ELEKTRISCHE BAUTEILE
1
Scheinwerfer
2
Spannungsregulator
3
Motorstoppschalter
4
Drosselklappensensor
5
Rücklicht
6
Leerlaufschalter
7
CDI-Schwungradmagnetzünder
8
Zündkerze
9
Zündspule
0
Lichtschalter
A
CDI-Zündbox
FARB-KODIERUNG
B ............................ schwarz
Br ........................... braun
G ............................ grün
Gy .......................... gran
L ............................. blau
O ............................ orange
P ............................ rosa
R ............................ rot
Sb .......................... hellblau
W ........................... weiß
Y ............................ gelb
B/L ......................... schwarz/blau
B/W ........................ schwarz/weiß
B/Y ......................... schwarz/gelb
G/B......................... grün/schwarz
L/W ........................ blau/weiß
R/W ........................ rot/weiß
SCHALTPLAN
* Nicht USA
PARTIE
ELECTRIQUE
COMPOSANTS ELECTRI-
QUES ET SCHEMA DE
CABLAGE
COMPOSANTS ELECTRIQUES
1
Phare
2
Régulateur de tension
3
Couper-circuit du moteur
4
Capteur de papillon des gaz
5
Feu arrière
6
Contacteur de point mort
7
Magnéto CDI
8
Bougie
9
Bobine d’allumage
0
Contacteur d’éclairage
A
Bloc CDI
CODE DE COULEUR
B............................ Noir
Br .......................... Brun
G ........................... Vert
Gy ......................... Gris
L ............................ Bleu
O ........................... Orange
P ............................ Rose
R............................ Rouge
Sb .......................... Bleu ciel
W........................... Blanc
Y ........................... Jaune
B/L ........................ Noir/Bleu
B/W ....................... Noir/Blanc
B/Y........................ Noir/Jaune
G/B........................ Vert/Noir
L/W ....................... Bleu/Blanc
R/W ....................... Rouge/Blanc
SCHEMA DE CABLAGE
* Excepté pour USA
6 - 1
IMPIANTO
ELETTRICO
COMPONENTI ELET-
TRICI E SCHEMA DI
CABLAGGIO
COMPONENTI ELETTRICI
1
Faro
2
Regolatore di tensione
3
Interruttore di arresto motore
4
Sensore di posizione valvola a far-
falla
5
Fanalino posteriore
6
Interruttore folle
7
Magnete CDI
8
Candela d’accensione
9
Bobina di accensione
0
Interruttore luci
A
Unità CDI
CODICE COLORE
B ................................nero
Br ...............................marrone
G ................................verde
Gy ..............................grigio
L ................................blu
O ................................arancione
P.................................rosa
R ................................rosso
Sb...............................azzurro
W ...............................bianco
Y ................................giallo
B/L.............................nero/blu
B/W ...........................nero/bianco
B/Y ............................nero/giallo
G/B ............................verde/nero
L/W............................blu/bianco
R/W ...........................rosso/bianco
SCHEMA DI CABLAGGIO
*Tranne USA





6

–+ELEC

6 - 2
MAP-CONTROLLED CDI UNIT
MAP-CONTROLLED CDI UNIT
A map-controlled, CDI ignition system is used in the WR250F.
The microcomputer in the CDI unit detects the engine speed and throttle position, thus determining
the optimum ignition timing through the entire operating range. In this way, quick throttle response
can be achieved according to various riding conditions.
CDI unit
Throttle position sensor
Pickup coil CDI magneto rotorIgnition coil


Function of Component

Component Function
Throttle position sensor Detects throttle valve opening and inputs it into the computer in the
CDI unit as a throttle opening signal.
Pickup coil Detects signal rotor revolutions and inputs them into the computer in
the CDI unit as engine revolution signals.
CDI unit The signals of the throttle position sensor and pickup coil sensor are
analyzed by the computer in the CDI unit, which then adjusts ignition
timing for the operation requirements.

Principal of 3-Dimensional Control
Conventionally, ignition timing was controlled only
by engine revolutions (2-dimensional control).
However, ignition timing needs advancement also
by engine load. Thus, accurate ignition timing can
be determined by adding throttle opening to deter-
mine ignition timing (3-dimensional control).
3-D Image Map of Ignition Timing
(different from actual characteristics)
Revolutions
Ignition timing
Throttle opening