2003 YAMAHA WR 250F engine oil

6 - 3
–+ELECMAP-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.






Function of Component






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 deter-
mined by adding throttle opening to determine ignition
timing (3-dimensional control).
3-D Image Map of Ignition Timing
(different from actual characteristics)
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.
CDI unit
Throttle position sensor
Pickup coil AC magneto rotorIgnition coil
Revolutions
Ignition timing
Throttle opening

6 - 8
–+ELECIGNITION SYSTEM
EC620000
IGNITION SYSTEM
INSPECTION STEPS
Use the following steps for checking the possibility of the malfunctioning engine being attributable to ignition system failure
and for checking the spark plug which will not spark.
*1 marked: Refer to “FUSE INSPECTION” section in the CHAPTER 3.
*2 marked: Refer to “BATTERY INSPECTION AND CHARGING” section in the CHAPTER 3.
*3 marked: Only when the ignition checker is used.
NOTE:Remove the following parts before inspection.
1) Seat
2) Fuel tank
Use the following special tools in this inspection.
*1 Check fuse.Replace fuse and check
wire harness.
*2 Check battery. Recharge or replace.
Spark gap test*3 Clean or replace spark
plug.
Check entire ignition system for
connection.
(couplers, leads and ignition coil)Repair or replace.
Check engine stop switch. Replace.
Check main switch.Replace.
Check ignition coil. Primary coil Replace.
Secondary coil Replace.
Check AC magneto. Pickup coil Replace.
Check neutral switch. Repair or replace.
Replace CDI unit.
Dynamic spark tester:
YM-34487
Ignition checker:
90890-06754
Pocket tester:
YU-3112-C/
90890-03112
No good
OK
No good
OK
Spark
No spark
No good
OK
No good
OK
No good
OK
No good
OKNo good
No good
OK
No good
OK

6 - 13
–+ELECIGNITION SYSTEM
SPARK GAP TEST
1. Disconnect the ignition coil from
spark plug.
2. Remove the ignition coil cap.
3. Connect the dynamic spark
tester
1 (ignition checker
2) as
shown.
Ignition coil
3
Spark plug
4
ÈFor USA and CDN
ÉExcept for USA and CDN
4. Kick the kickstarter crank.
5. Check the ignition spark gap.
6. Start engine, and increase spark
gap until misfire occurs. (for USA
and CDN only)
Minimum spark gap:
6.0 mm (0.24 in)
È
É
COUPLERS, LEADS AND
IGNITION COIL CONNECTION
INSPECTION
1. Check:
Couplers and leads connec-
tion
Rust/dust/looseness/short-cir-
cuit
→ Repair or replace.
Ignition coil and spark plug as
they are fitted
Push in the ignition coil until it
closely contacts the spark plug
hole in the cylinder head
cover.
ENGINE STOP SWITCH
INSPECTION
1. Inspect:
Engine stop switch conduct
No continuity while being pushed
→
Replace.
Continuity while being freed
→
Replace.Tester (+) lead →
Black lead 1

Tester (–) lead →
Black lead 2

B
1
B
2
Tester
selector
position
PUSH IN
Ω
×
1
FREE
TEST DE LA LONGUEUR
D’ETINCELLE D’ALLUMAGE
1. Déconnecter la bobine d’allumage
de la bougie.
2. Déposer le capuchon de la bobine
d’allumage.
3. Connecter le testeur dynamique
d’étincelle 1 (testeur d’allumage
2) comme indiqué.
Bobine d’allumage 3
Bougie 4
È
USA et CDN
É
Excepté USA et CDN
4. Actionner le kick.
5. Contrôler la longueur d’étincelle
d’allumage.
6. Démarrer le moteur et augmenter la
longueur d’étincelle jusqu’à ce
qu’un raté se produise. (uniquement
USA et CDN)
Longueur d’étincelle
minimum:
6,0 mm (0,24 in)
CONTROLE DES CONNEXIONS
DES RACCORDS, FILS ET BOBINE
D’ALLUMAGE
1. Contrôler:
Connexion de coupleurs et fils
Rouille/poussière/jeu/court-cir-
cuit → Réparer ou remplacer.
Bobine d’allumage et bougie tel-
les quelles
Insérer la bobine d’allumage
jusqu’à ce qu’elle touche le trou
de bougie dans le couvercle de la
culasse.
CONTROLE DU COUPE-CIRCUIT
DU MOTEUR
1. Contrôler:
Continuité du coupe-circuit du
moteur
Pas de continuité lorsqu’enfoncé →
Remplacer.
Continuité lorsque relâché → Rempla-
cer.Fil (+) de multimètre → Fil noir 1
Fil (–) de multimètre → Fil noir 2
B
1 B
2 Position de
sélecteur du
multimètre
ENFONCE
Ω × 1
RELACHE
SYSTEME D’ALLUMAGE

6 - 45
–+ELECCHARGING SYSTEM
EC680000
CHARGING SYSTEM
EC681001INSPECTION STEPS
If the battery is not charged, use the following inspection steps.
*1 marked: Refer to “FUSE INSPECTION” section in the CHAPTER 3.
*2 marked: Refer to “BATTERY INSPECTION AND CHARGING” section in the CHAPTER 3.
NOTE:Remove the following parts before inspection.
1) Seat
2) Fuel tank
Use the following special tool in this inspection.
*1 Check fuse.Replace fuse and check
wire harness.
*2 Check battery. Recharge or replace.
Check each coupler and wire
connection.Repair or replace.
Check charging voltage. Charging system is good.
Check AC magneto. Charging coil Replace.
Replace rectifier/regulator.
Pocket tester:
YU-3112-C/
90890-03112
Inductive tachometer:
YU-8036-B
Engine tachometer:
90890-03113
No good
OK
No good
OK
No good
OK
OK
No good
No good
OK

6 - 51
–+ELECCHARGING SYSTEM
EC624000COUPLERS AND LEADS
CONNECTION INSPECTION
1. Check:
Couplers and leads connec-
tion
Rust/dust/looseness/short-cir-
cuit
→ Repair or replace.
CHARGING VOLTAGE
INSPECTION
1. Start the engine.
2. Inspect:
Charging voltage
Out of specification
→ If no
failure is found in checking the
source coil resistance, replace
the rectifier/regulator.
Tester (+) lead →
Red lead 1

Tester (–) lead →
Black lead 2

Charging
voltageTester
selector
position
14.1 ~ 14.9 V
at 5,000 r/minDCV-20
R
BW Y1
2
3. Inspect:
Charging coil resistance
Out of specification
→
Replace.
Tester (+) lead →
White lead 1

Tester (–) lead →
Ground 2

Charging coil
resistanceTester
selector
position
0.288 ~ 0.432 Ω

at 20 °C (68 °F)Ω
×
1
INSPECTION DE LA CONNEXION
DES RACCORDS ET DES FILS
1. Contrôler:
Connexion des raccords et des
fils
Rouille/poussière/desserrage/
court-circuit → Réparer ou rem-
placer.
INSPECTION DE LA TENSION DE
CHARGE
1. Démarrer le moteur.
2. Contrôler:
Tension de charge
Hors spécification → Si aucune
erreur n’est détectée lors du con-
trôle de la résistance de la bobine
source, remplacer le redresseur/
régulateur.
Fil (+) de multimètre → Fil rouge 1
Fil (–) de multimètre → Fil noir 2
Tension de
chargePosition de
sélecteur du
multimètre
14,1 à 14,9 V à
5.000 tr/mnDCV-20
3. Contrôler:
Résistance de la bobine de charge
Hors spécification → Remplacer.
Fil (+) de multimètre → Fil blanc 1
Fil (–) de multimètre → Masse 2
Résistance de la
bobine de
chargePosition de
sélecteur du
multimètre
0,288 à 0,432 Ω
à 20 °C (68 °F)Ω × 1
SYSTEME DE RECHARGE

6 - 53
–+ELECTHROTTLE POSITION SENSOR SYSTEM
THROTTLE POSITION SENSOR SYSTEM
INSPECTION STEPS
If the throttle position sensor will not operate, use the following inspection steps.
NOTE:Use the following special tools in this inspection.
Check entire ignition
system for connection.Repair or replace.
Check throttle position sensor.Throttle position
sensor coilReplace.
Check CDI unit.Throttle position
sensor input
voltageReplace.
Pocket tester:
YU-3112-C/
90890-03112
Inductive tachometer:
YU-8036-B
Engine tachometer:
90890-03113
No good
OK
No good
OK
No good

6 - 59
–+ELECTHROTTLE POSITION SENSOR SYSTEM
HANDLING NOTE
CAUTION:
Do not loosen the screws (throttle
position sensor) 1
except when
changing the throttle position sen-
sor due to failure because it will
cause a drop in engine perfor-
mance.
1
EC624000COUPLERS AND LEADS
CONNECTION INSPECTION
1. Check:
Couplers and leads connec-
tion
Rust/dust/looseness/short-cir-
cuit
→ Repair or replace.
THROTTLE POSITION SENSOR
COIL INSPECTION
1. Inspect:
Throttle position sensor coil
resistance
Out of specification
→
Replace.
Tester (+) lead →
Blue lead 1

Tester (–) lead →
Black lead 2
Throttle
position
sensor coil
resistanceTester
selector
position
4 ~ 6 kΩ at
20 °C (68 °F)kΩ × 1
2. Loosen:
Throttle stop screw 1
NOTE:Turn out the throttle stop screw until
the throttle shaft is in the full close
position.
REMARQUE
ATTENTION:
Ne pas desserrer les vis (capteur de
position des gaz) 1 sauf s’il faut chan-
ger le capteur de position en raison
d’un problème, sinon le moteur sera
moins performant.
CONTROLE DES CONNEXIONS
DES COUPLEURS ET DES FILS
1. Contrôler:
Connexion coupleurs et fils
Rouille/poussière/desserrement/
court-circuit → Réparer ou rem-
placer.
CONTROLE DE LA BOBINE DE
CAPTEUR DE PAPILLON DES
GAZ
1. Contrôler:
Résistance de la bobine du cap-
teur de papillon des gaz
Hors spécifications → Rempla-
cer.
Fil (+) de multimètre → Fil bleu 1
Fil (–) de multimètre → Fil noir 2
Résistance de la
bobine du
capteur de
papillon des gaz Position de
sélecteur du
multimètre
4 à 6 kΩ à
20 °C (68 °F)kΩ × 1
2. Desserrer:
Vis d’arrêt d’accélérateur 1
N.B.:
Tourner la vis d’arrêt d’accélérateur
jusqu’à ce que l’axe de l’accélérateur
soit en position de fermeture complète.
CIRCUIT DU CAPTEUR DE PAPILLON DES GAZ

6 - 67
–+ELECLIGHTING SYSTEM
LIGHTING SYSTEM
INSPECTION STEPS
Refer to the following flow chart when inspecting the ignition system for possible problems.
NOTE:Replace the bulb and/or bulb socket.
1) Seat
2) Fuel tank
Use the following special tool.
Check the bulb and bulb socket.Replace the bulb and/or
bulb socket.
Check the light switch. Replace.
Check the AC magneto. Lighting coil Replace.
Check the entire lighting system
proper for connections.Repair or replace.
Check the rectifier/regulator. Out-put voltage Replace.
Pocket tester:
YU-3112-C/
90890-03112
Inductive tachometer:
YU-8036-B
Engine tachometer:
90890-03113
No good
OK
No good
OK
No good
OK
Improperly connected
OK
No good