2004 YAMAHA WR 450F engine

6 - 4
–+ELEC

IGNITION 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

Å
For USA and CDN
ı
Except for USA and CDN
4. Kick the kickstarter.
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)
Å
ı

COUPLERS, LEADS AND IGNITION COIL
CONNECTION INSPECTION
1. Check:

Couplers and leads connection
Rust/dust/looseness/short-circuit
→

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 cyl-
inder head cover.
EC625001
“ENGINE STOP” BUTTON INSPECTION
1. Inspect:
“ENGINE STOP” button conduct
No continuity while being pushed → Replace.
Continuity while being freed → Replace.
2. Inspect:
Rubber part a
Tears/damage → Replace. Tester (+) lead → Black lead 1
Tester (–) lead → Black lead 2
B
1B
2Tester selector
position
PUSH IN
Ω × 1
FREE
a

–+ELEC
SYSTEME D’ALLUMAGE
ZÜNDANLAGE
SISTEMA DE ENCENDIDO
ZÜNDFUNKENSTRECKE KON-
TROLLIEREN
1. Die Zündspule von der Zünd-
kerze abtrennen.
2. Die Zündspule ausbauen.
3. Den Zündfunkenstreckente-
ster 1 (bzw. 2) wie abgebil-
det anschließen.
Zündspule 3
Zündkerze 4
ÅNur USA und CDN
ıNicht USA und CDN
4.Den Motor mit dem Kick-
starter durchdrehen
.
5. Die Zündfunkenstrecke kon-
trollieren.
6. Den Motor anlassen und die
Zündfunkenstrecke vergrö-
ßern, bis es zu Fehlzündungen
kommt (nur USA und CDN).
STECKVERBINDER-, KABEL- UND
ZÜNDSPULENANSCHLÜSSE
KONTROLLIEREN
1. Kontrollieren:
Steckverbinder- und Kabel-
anschlüsse
Rost/Staub/Lockerheit/Kurz-
schluß → Instand setzen
oder erneuern.
Zündspule und Zündkerze
wie angebracht
Die Zündspule eindrücken,
bis sie das Zündkerzenloch
im Zylinderkopfdeckel fest
berührt.
MOTORSTOPPSCHALTER “ENGI-
NE STOP” KONTROLLIEREN
1. Kontrollieren:
Motorstoppschalter
(auf Durchgang)
Kein Durchgang bei gedrücktem
Schalter → Erneuern.
Durchgang bei freigelassenem
Schalter → Erneuern.
2. Kontrollieren:
Gummiteil a
Risse/Schäden → Erneuern.
Min. Zündfunkenstrecke:
6,0 mm (0,24 in)
Meßkabel (+) →
Schwarz Kabel 1
Meßkabel (–) →
Schwarz Kabel 2
B
1 B
2 Meßge-
rät-
Einstel-
GE-
DRÜCKT
Ω × 1
FREI
TEST DE L’INTERVALLE D’ETIN-
CELLEMENT D’ALLUMAGE
1. Débrancher la bobine d’allumage
de la bougie.
2. Déposer la bobine d’allumage.
3. Connecter le testeur dynamique
d’étincelle 1 (testeur d’allu-
mage 2) comme indiqué.
Bobine d’allumage 3
Bougie 4
ÅPour les USA et le CDN
ıExcepté pour les USA et le CDN
4. Actionner le démarreur au pied.
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. (unique-
ment USA et CDN)
INSPECTION 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.
Mise en place de la bobine
d’allumage et de la bougie
Enfoncer la bobine d’allumage
jusqu’à ce qu’elle touche bien
l’orifice de la bougie dans le
couvercle de culasse.
CONTROLE DU BOUTON
D’ARRET DU MOTEUR “ENGINE
STOP”
1. Vérifier:
Continuité du bouton d’arrêt du
moteur “ENGINE STOP”
Pas de continuité lorsque enfoncé →
Remplacer.
Continuité lorsque relâché → Rempla-
cer.
2. Vérifier:
Pièce en caoutchouc a
Fissures/Dommage → Rempla-
cer.
Longueur d’étincelle mini-
mum:
6,0 mm (0,24 in)
Fil (+) de multimètre → Fil noir 1
Fil (–) de multimètre → Fil noir 2
B
1B
2Position de
sélecteur
du multi-
mètre
EN-
FONCE
Ω × 1
RE-
LACHE
6 - 4
PRUEBA DE LA SEPARACIÓN
ENTRE PUNTAS DE LA BUJÍA
1. Desconecte la bobina de encen-
dido de la bujía.
2. Quite la tapa de la bobina de
encendido.
3. Conecte el tester dinámico de la
bujía 1 (comprobador de encen-
dido 2) tal y como se muestra.
Bobina de encendido 3
Bujía 4
ÅPara USA y CDN
ıExcepto para USA y CDN
4. Accione el arrancador del pedal.
5. Compruebe la separación entre
puntas de la bujía de encendido.
6. Arranque el motor e incremente la
separación entre puntas de la bujía
hasta que deje de saltar la chispa
(solamente para USA y CDN).
IMPECCIÓN DE LA CONEXIÓN
DE LOS ACOPLADORES, CABLES
Y BOBINA DE ENCENDIDO
1. Comprobar:
Conexión de acopladores y cables
Oxido/polvo/flojedad/cortocir-
cuito → Reparar o reemplazar.
Bobina de encendido y bujía
para ver cómo están colocadas
Presione hacia dentro la bobina
de encendido hasta que esté bien
en contacto con el orificio de la
bujía de la cubierta de la culata.
INSPECCIÓN DEL BOTÓN DE
PARADA DE MOTOR “ENGINE
STOP”
1. Inspeccionar:
Conducto del botón de parada
de motor “ENGINE STOP”
Sin continuidad mientras se mantiene
pulsado → Reemplazar.
Con continuidad mientras se suelta →
Reemplazar.
2. Inspeccionar:
Parte de goma a
Cortes/daños → Reemplazar.
Separación entre puntas
mínima de la bujía:
6,0 mm (0,24 in)
Cable del tester (+) →
Cable negro 1
Cable del tester (–) →
Cable negro 2
B
1B
2Posición
del selec-
tor del tes-
ter
PUL-
SAR
Ω × 1
LIBRE

6 - 7
–+ELEC
ELECTRIC STARTING SYSTEM
STARTING CIRCUIT CUT-OFF SYSTEM
OPERATION
If the main switch is set to “ON”, the starter
motor can only operate if at least one of the
following conditions is met:
The transmission is in neutral (the neutral
switch is closed).
The clutch lever is pulled to the handlebar
(the clutch switch is closed).
The starting circuit cut-off relay prevents the
starter motor from operating when neither of
these conditions has been met. In this
instance, the starting circuit cut-off relay is
open so current cannot reach the starter
motor. When at least one of the above condi-
tions has been met the starting circuit cut-off
relay is closed and the engine can be started
by pressing the start switch.
WHEN THE TRANSMISSION IS
IN NEUTRAL
WHEN THE CLUTCH LEVER IS
PULLED TO THE HANDLEBAR
1Battery
2Main fuse
3Main switch
4Starting circuit cut-off relay
5Start switch
6Diode
7Clutch switch
8Neutral switch
9Starter relay
0Starter motor
12
M
3
4
5
8 76 9
0
ELECTRIC STARTING SYSTEM

6 - 12
–+ELECELECTRIC STARTING SYSTEM
STARTER MOTOR
0
9
56
7
5 0 8
9
4
3
2
1
New
New
New
B
5
1
Extent of removal:1 Starter motor disassembly
Extent of removal Order Part name Q’ty Remarks
STARTER MOTOR REMOVAL
Preparation for removal Drain the engine oil. Refer to “ENGINE OIL REPLACEMENT”
section in the CHAPTER 3.
Crankcase cover (left) Refer to “AC MAGNETO AND
STARTER CLUTCH” section in the
CHAPTER 4.
1 Starter motor 1
STARTER MOTOR DISASSEM-
BLY
1Starter motor front cover 1
2Washer (starter motor front
cover)1
3Plain washer 1
4Circlip 1
5O-ring
3
1

6 - 18
–+ELECCHARGING SYSTEM
EC624000
COUPLERS AND LEADS CONNECTION
INSPECTION
1. Check:
Couplers and leads connection
Rust/dust/looseness/short-circuit →
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 resis-
tance, 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

6 - 20
–+ELECTPS (THROTTLE POSITION SENSOR) SYSTEM
HANDLING NOTE
CAUTION:
Do not loosen the screws {TPS (throttle
position sensor)} 1 except when changing
the TPS (throttle position sensor) due to
failure because it will cause a drop in
engine performance.
1
EC624000
COUPLERS AND LEADS CONNECTION
INSPECTION
1. Check:
Couplers and leads connection
Rust/dust/looseness/short-circuit →
Repair or replace.
TPS COIL INSPECTION
1. Inspect:
TPS coil resistance
Out of specification → Replace.
2. Loosen:
Throttle stop screw 1
NOTE:
Turn out the throttle stop screw until the throt-
tle shaft is in the full close position.Tester (+) lead → Blue lead 1
Tester (–) lead → Black lead 2
TPS coil
resistanceTester selector
position
4 ~ 6 kΩ at
20 ˚C (68 ˚F)kΩ × 1

6 - 22
–+ELECTPS (THROTTLE POSITION SENSOR) SYSTEM
4. Adjust:
Idle speed
Refer to “IDLE SPEED ADJUST-
MENT” section in the CHAPTER 3.
5. Insert the thin electric conductors 2
(lead) into the TPS coupler 1, as shown,
and connect the tester to them.
CAUTION:
Do not insert the electric conductors
more than required because it may
reduce the waterproof function of the
coupler.
Make sure that a short-circuit does not
develop between the terminals because it
may cause damage to electrical compo-
nents.
6. Start the engine.Tester (+) lead → Yellow lead 3
Tester (–) lead → Black lead 4
7. Adjust:
TPS output voltage
Adjustment steps:
Adjust the installation angle of the TPS 1
to obtain the specified output voltage.
NOTE:
Measure the output voltage accurately with a
digital electronic voltmeter that gives an easy
reading of a small voltage.
TPS output
voltageTester selector
position
0.58 ~ 0.78 V DCV

6 - 23
–+ELECTPS (THROTTLE POSITION SENSOR) SYSTEM
8. Tighten:
Screw (TPS) 1
9. Stop the engine.
1
EC694000
TPS INPUT VOLTAGE INSPECTION
1. Disconnect the TPS coupler.
2. Start the engine.
3. Inspect:
TPS input voltage
Out of specification → Replace the CDI
unit.
Tester (+) lead → Blue lead 1
Tester (–) lead → Black/Blue lead 2
TPS input
voltageTester selector
position
4 ~ 6 V DCV-20