stop start YAMAHA WR 400F 2002 User Guide

3 - 19
INSP
ADJIDLE SPEED ADJUSTMENT/
VALVE CLEARANCE ADJUSTMENT
EC35M021
IDLE SPEED ADJUSTMENT
1. Start the engine and thoroughly warm it
up.
2. Adjust:
Idle speed
Adjustment steps:
Adjust the pilot screw.
Refer to “PILOT SCREW ADJUSTMENT”
section.
Turn the throttle stop screw 1 until the
engine runs at the lowest possible speed.
To increase idle speed →
Turn the throttle stop screw 1 in a.
To decrease idle speed →
Turn the throttle stop screw 1 out b.
Engine idling speed:
1,700 ~ 1,900 r/min
VALVE CLEARANCE ADJUSTMENT
NOTE:
The valve clearance should be adjusted
when the engine is cool to the touch.
The piston must be at Top Dead Center
(T.D.C.) on compression stroke to check or
adjust the valve clearance.
1. Remove:
Seat
Fuel tank
Refer to “SEAT, FUEL TANK AND SIDE
COVERS” section in the CHAPTER 4.
2. Remove:
Carburetor
Refer to “CARBURETOR” section in
the CHAPTER 4.
Spark plug cap
Engine stay (upper)
Cylinder head cover
Refer to “CAMSHAFTS” section in the
CHAPTER 4.
3. Remove:
Timing plug 1
Straight plug 2
O-ring

4 - 17
ENGCARBURETOR
10. Install:
Starter jet 1
Pilot jet 2
Spacer 3
Needle jet 4
Main jet 5
11. Install:
Valve seat
Screw (valve seat) 1
Needle valve 2
Float 3
Float pin 4
NOTE:
After installing the needle valve to the float,
install them to the carburetor.
Check the float for smooth movement.
12. Install:
Pilot screw 1
Spring 2
Washer 3
O-ring 4
* Except for USANote the following installation points:
Turn in the pilot screw until it is lightly
seated.
Turn out the pilot screw by the number of
turns recorded before removing.
Pilot screw:
WR426F: 1-5/8 turns out
*1-1/8 turns out
WR400F: 1-1/2 turns out
(example)
13. Install:
O-ring
Float chamber 1
Screw (float chamber) 2
Cable holder (throttle stop screw cable)
3
Hose holder (carburetor breather hose)
4
ÅWR426F
ıWR400F Å

6 - 4
–+ELEC

IGNITION SYSTEM
EC622001
SPARK GAP TEST
1. Disconnect the spark plug cap from spark
plug.
2. Connect the dynamic spark tester
1
(ignition checker
2
) as shown.

Spark plug cap
3


Spark plug
4

Å
For USA and CDN
ı
Except for USA and CDN
3. Kick the kick starter.
4. Check the ignition spark gap.
5. 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

EC624000
COUPLERS AND LEADS CONNECTION
INSPECTION
1. Check:

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

Repair or replace.
EC625001
“ENGINE STOP” BUTTON INSPECTION
1. Inspect:

“ENGINE STOP” button conduct
No continuity while being pushed
→
Replace.
Continuity while being freed
→
Replace.
Tester (+) lead
→
Black/White lead
1

Tester (–) lead
→
Black lead
2

B/W
1
B
2
Tester selec-
tor position
PUSH IN
Ω

×
1
FREE

–+ELEC
SYSTEME D’ALLUMAGE
ZÜNDANLAGE
SISTEMA DE ENCENDIDO
ZÜNDFUNKENSTRECKE KON-
TROLLIEREN
1. Den Zündkerzenstecker von
der Zündkerze abziehen.
2. Den Zündfunkenstreckente-
ster 1 (bzw. 2) wie abgebil-
det anschließen.
Zündkerzenstecker 3
Zündkerze 4
ÅNur USA und CDN
ıNicht USA und CDN
3.Den Motor mit dem Kick-
starter durchdrehen
.
4. Die Zündfunkenstrecke kon-
trollieren.
5. Den Motor anlassen und die
Zündfunkenstrecke vergrö-
ßern, bis es zu Fehlzündun-
gen kommt (nur USA und
CDN).
Min. Zündfunkenstrecke
6,0 mm
STECKVERBINDER- UND KABEL-
ANSCHLÜSSE KONTROLLIEREN
1. Kontrollieren:
Steckverbinder- und Kabel-
anschlüsse
Rost/Staub/Lockerheit/Kurz-
schluß → Instand setzen
oder erneuern.
MOTORSTOPPSCHALTER “ENGI-
NE STOP” KONTROLLIEREN
1. Kontrollieren:
Motorstoppschalter
(auf Durchgang)
Kein Durchgang bei gedrücktem
Schalter → Erneuern.
Durchgang bei freigelassenem
Schalter → Erneuern. Meßkabel (+) →
Schwarz/Weiß Kabel 1
Meßkabel (–) →
Schwarz Kabel 2
B/W
1 B
2 Meßge-
rät-
Einstel-
GE-
DRÜCKT
Ω × 1
FREI
TEST DE L’INTERVALLE D’ETIN-
CELLEMENT D’ALLUMAGE
1. Déconnecter le capuchon de bou-
gie de la bougie.
2. Connecter le testeur dynamique
d’étincelle 1 (testeur d’allu-
mage 2) comme indiqué.
Capuchon de bougie 3
Bougie 4
ÅPour les USA et le CDN
ıExcepté pour les USA et le CDN
3. Actionner le démarreur au pied.
4. Contrôler la longueur d’étincelle
d’allumage.
5. Démarrer le moteur et augmenter
la longueur d’étincelle jusqu’à ce
qu’un raté se produise. (unique-
ment USA et CDN)
Longueur d’étincelle mini-
mum:
6,0 mm (0,24 in)
CONTROLE DES CONNEXIONS
DE COUPLEURS ET FILS
1. Contrôler:
Connexion de coupleurs et fils
Rouille/poussière/jeu/court-cir-
cuit → Réparer ou changer.
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 →
Changer.
Continuité lorsque relâché → Changer. Fil (+) de multimètre →
Fil noir/blanc 1
Fil (–) de multimètre → Fil noir 2
B/W
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 tapa de puntas de
la bujía de la bujía misma.
2. Conecte el tester dinámico de la
bujía 1 (comprobador de encen-
dido 2) tal y como se muestra.
Tapa de la bujía 3
Bujía 4
ÅPara USA y CDN
ıExcepto USA y CDN
3. Accione el arrancador del pedal.
4. Compruebe la separación entre
puntas de la bujía de encendido.
5. Arranque el motor e incremente
la separación entre puntas de la
bujía hasta que deje de saltar la
chispa (solamente para USA y
CDN).
Separación entre puntas
mínima de la bujía:
6,0 mm (0,24 in)
INSPECCIÓN DE ACOPLADORES
Y CONEXIÓN DE CABLES
1. Comprobar:
Conexión de acopladores y
cables
Oxido/polvo/flojedad/cortocir-
cuito → Reparar o reemplazar.
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.Cable del tester (+) →
Cable negro/blanco 1
Cable del tester (–) →
Cable negro 2
B/W
1B
2Posición
del selec-
tor del tes-
ter
PULSAR
(PUSH
IN)
Ω × 1
LIBRE

6 - 10
–+ELECTPS (THROTTLE POSITION SENSOR) SYSTEM
4. Adjust:
Idle speed
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 dose not
develop between the terminals because it
may cause damage to electrical compo-
nents. Adjustment steps:
Attach the inductive tachometer (engine
tachometer) to the high tension cord.
Turn the throttle stop screw 1 until the
specified idle speed.
Refer to “IDLE SPEED ADJUSTMENT”
section in the CHAPTER 3.
Idle speed:
1,700 ~ 1,900 r/min
Tester (+) lead → Yellow lead 3
Tester (–) lead → Black lead 4
6. Start the engine.
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 - 11
–+ELEC
8. Tighten:
Screw (TPS) 1
9. Stop the engine.
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
TPS (THROTTLE POSITION SENSOR) SYSTEM

–+ELEC
8. Festziehen:
Schraube (TPS) 1
9. Den Motor Stoppen
PRÜFEN DER TPS-EINGANGS-
SPANNUNG
1. Die TPS-Steckverbindung
trennen.
2. Den Motor starten.
3. Prüfen:
TPS-Eingangsspannung
Außerhalb des Sollwerts →
Die CDI-Einheit austau-
schen.
Prüfgerätkabel (+) →
Blaues Kabel 1
Prüfgerätkabel (–) →
Schwarzes/Blaues Kabel 2
TPS-Ein-
gangs-
spannung Prüfgeräte-
instellung
4–6 V DCV-20
8. Serrer:
Vis (TPS) 1
9. Arrêter le moteur
CONTROLE DE LA TENSION
D’ENTREE DU TPS
1. Débrancher le coupleur de TPS.
2. Démarrer le moteur.
3. Contrôler:
Tension d’entrée du TPS
Hors spécifications → Rempla-
cer le bloc CDI.
Fil (+) de multimètre → Fil bleu 1
Fil (–) de multimètre →
Fil noir/bleu 2
Tension
d’entrée du
TPS Position du
sélecteur de
multimètre
4 à 6 V DCV-20
8. Apretar:
Tornillo (TPS) 1
9. Parar el motor
INSPECCIÓN DE LA TENSIÓN DE
ENTRADA DEL TPS
1. Desconectar el acoplador TPS.
2. Arrancar el motor.
3. Inspeccionar:
Tensión de entrada del TPS
Fuera de especificaciones →
Reemplazar.
Cable del tester (+) →
Cable azul 1
Cable del tester (–) →
Cable negro/azul 2
Tensión de
entrada del
TPSPosición del
selector del
tester
4 ~ 6 V DCV-20
SYSTEME TPS (CAPTEUR DU PAPILLON D’ACCELERATION)
TPS-SYSTEM (DROSSELKLAPPEN-POSITIONSSENSOR)
SISTEMA TPS (SENSOR DE POSICIÓN DEL ACELERADOR)
6 - 11

7 - 2
TUN
CAUTION:
The carburetor is extremely sensitive to
foreign matter (dirt, sand, water, etc.).
During installation, do not allow foreign
matter to get into the carburetor.
Always handle the carburetor and its
components carefully. Even slight
scratches, bends or damage to carbure-
tor parts may prevent the carburetor from
functioning correctly. Carefully perform
all servicing with the appropriate tools
and without applying excessive force.
When the engine is stopped or when
riding at no load, do not open and close
the throttle unnecessarily. Otherwise, too
much fuel may be discharged, starting
may become difficult or the engine may
not run well.
After installing the carburetor, check that
the throttle operates correctly and opens
and closes smoothly.
Atmospheric conditions and carburetor
settings
The air density (i.e., concentration of oxygen
in the air) determines the richness or lean-
ness of the air/fuel mixture. Therefore, refer
to the above table for mixture settings.
That is:
Higher temperature expands the air with its
resultant reduced density.
Higher humidity reduces the amount of oxy-
gen in the air by so much of the water vapor
in the same air.
Lower atmospheric pressure (at a high alti-
tude) reduces the density of the air.
Air temp. HumidityAir
pressure
(altitude)Mixture Setting
High High Low (high) Richer Leaner
Low Low High (low) Leaner Richer
SETTING