2005 YAMAHA WR 450F engine

6 - 4
–+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 (igni-
tion checker 2) as shown.
Ignition coil 3
Spark plug 4
ÈFor USA and CDN
ÉExcept 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)
È
É
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 fit-
ted
Push in the ignition coil until it closely
contacts the spark plug hole in the cylin-
der 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
1 B
2 Tester selec-
tor position
PUSH IN
Ω
×
×× × 1
FREE
a

–+ELEC
ZÜNDFUNKENSTRECKE
KONTROLLIEREN
1. Das Zündkabel von der Zünd-
kerze abziehen.
2. Den Stecker von der Zündspule
abziehen.
3. Den Zündfunkenstrecken-Tester
1 (Zündungstester 2), wie in der
Abbildung gezeigt, anschließen.
Zündspule 3
Zündkerze 4
È
USA und CDN
É
Nicht USA und CDN
4. Den Kickstarter betätigen.
5. Die Zündfunkenstrecke kontrol-
lieren.
6. Den Motor starten und dann die
Zündfunkenstrecke vergrößern,
bis es zu Fehlzündungen
kommt. (USA und CDN)
Min. Zündfunkenstrecke:
6,0 mm (0,24 in)
STECKVERBINDER-, KABEL- UND
ZÜNDSPULENANSCHLÜSSE
KONTROLLIEREN
1. Kontrollieren:
Steckverbinder- und Kabelan-
schlüsse
Rostig/staubig/locker/kurzge-
schlossen → Instand setzen,
ggf. erneuern.
Sitz der Zündspule und Zünd-
kerze
Die Zündspule eindrücken, bis
sie die Zündkerzenbohrung im
Zylinderkopfdekkel berührt.
MOTORSTOPPSCHALTER
“ENGINE STOP” KONTROLLIEREN
1. Kontrollieren:
Durchgang des Motorstopp-
schalters “ENGINE STOP”
Kein Durchgang, wenn gedrückt. →
Erneuern.
Durchgang, wenn freigegeben →
Erneuern.
2. Kontrollieren:
Gummiteil
a
Rissig/beschädigt → Erneuern. Meßkabel (+) → Schwarz 1
Meßkabel (–) → Schwarz 2
B
1 B
2 Meßgerät-
Wahlschal-
ter
EIN-
DRÜK-
KEN
Ω × 1
FREI-
GEBEN
TEST DE LA LONGUEUR
D’ETINCELLE
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 (contrôleur d’allu-
mage 2) comme indiqué.
Bobine d’allumage 3
Bougie 4
È
USA et CDN
É
Sauf 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. (USA et
CDN)
Longueur d’étincelle mini-
mum:
6,0 mm (0,24 in)
CONTROLE DES CONNEXIONS
DES FICHES RAPIDES, DES FILS
ET DE LA BOBINE D’ALLUMAGE
1. Contrôler:
Connexion des fiches rapides et
des fils
Rouille/poussière/jeu/court-cir-
cuit → Réparer ou remplacer.
Bobine d’allumage et bougie en
place
Appuyer sur la bobine d’allu-
mage jusqu’à ce qu’elle soit en
contact étroit avec le trou de bou-
gie du couvre-culasse.
CONTROLE DU BOUTON
“ENGINE STOP”
1. Contrôler:
Continuité du bouton “ENGINE
STOP”
Pas de continuité lorsque enfoncé →
Remplacer.
Continuité lorsque relâché → Rempla-
cer.
2. Contrôler:
Pièce en caoutchouc
a
Déchirures/endommagement →
Remplacer. Fil (+) du multimètre → fil noir 1
Fil (–) du multimètre → fil noir 2
B
1 B
2 Position du
sélecteur du
multimètre
ENFON-
CE
Ω × 1RELA-
CHE
PRUEBA DE LA BUJÍA
1. Desconecte la bobina de encendido
de la bujía.
2. Retire la tapa de la bobina de encen-
dido.
3. Conecte el comprobador dinámico
1 (comprobador de encendido 2)
como se muestra.
Bobina de encendido 3
Bujía 4
È
USA y CDN
É
Excepto USA y CDN
4. Accione el pedal de arranque.
5. Compruebe la distancia entre elec-
trodos de la bujía.
6. Arranque el motor e incremente la
distancia entre electrodos hasta que
el encendido falle (USA y CDN).
Distancia entre electrodos
mínima:
6,0 mm (0,24 in)
COMPROBACIÓN DE LA
CONEXIÓN DE ACOPLADORES,
CABLES Y BOBINA DE ENCENDIDO
1. Comprobar:
Conexión de acopladores y cables
Óxido/polvo/flojas/cortocircuito
→ Reparar o cambiar.
La bobina de encendido y la bujía
tal como están
Empuje la bobina de encendido
hacia adentro hasta que toque el
orificio de la bujía en la tapa de la
culata.
COMPROBACIÓN DEL BOTÓN
“ENGINE STOP”
1. Comprobar:
Conducto del botón “ENGINE
STOP”
No hay continuidad cuando se pulsa →
Cambiar.
Hay continuidad cuando se suelta →
Cambiar.
2. Comprobar:
Pieza de goma
a
Rotura/daños → Cambiar. Cable (+) del comprobador →
Cable negro 1
Cable (–) del comprobador →
Cable negro 2
B
1 B
2 Posición del
selector del
comprobador
EMPU-
JAR
Ω × 1SOL-
TAR
SYSTEME D’ALLUMAGE
ZÜNDSYSTEM
SISTEMA DE ENCENDIDO
6 - 4

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 fol-
lowing 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
1 Starter motor front cover 1
2 Washer (starter motor front
cover)1
3 Plain washer 1
4 Circlip 1
5 O-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 ADJUSTMENT”
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