2000 YAMAHA WR 400F engine

–+ELECSISTEMA DE ENCENDIDO
SISTEMA DE ENCENDIDO
PASOS PARA LA INSPECCIÓN
Utilice los siguientes pasos para comprobar la posibilidad de un funcionamiento incorrecto del motor con res-
pecto a un fallo del sistema de encendido o para comprobar que la bujía no enciende.
*: Únicamente cuando se utilice el comprobador de encendido.
NOTA:
lAntes de llevar a cabo la inspección, extraiga las siguientes piezas.
1) Asiento
2) Depósito de combustible
lUtilice las siguientes herramientas especiales para la inspección.
Prueba de la separación entre
puntas de la bujía* Limpiar o reemplazar la
bujía.
Comprobar la conexión de todo el
sistema de encendido.Reparar o reemplazar.
Comprobar el botón de parada de
motor “ENGINE STOP”.Reemplazar.
Comprobar la bobina de encen-
dido.Bobina primaria Reemplazar.
Bobina secunda-
riaReemplazar.
Comprobar el magneto CDI.Bobina de acele-
ración rápidaReemplazar.
Bobina de fuente Reemplazar.
Comprobar el interruptor de
punto muerto.Reparar o reemplazar.
Reemplazar la unidad CDI.
Tester dinámico de bujía:
YM-34487
Comprobador de encendido:
90890-06754Tester de bolsillo:
YU-03112/90890-03112
Sin chispa
OK
Chispa
Incorrecta
Incorrecta
Incorrecta
Incorrecta
Incorrecta
Incorrecta
Incorrecta
OK
OK
OK
OK
6 - 3

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.
l
Spark plug cap
3

l
Spark plug
4


For USA and CDN
õ
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)

õ

EC624000
COUPLERS AND LEADS CONNECTION
INSPECTION
1. Check:
l
Couplers and leads connection
Rust/dust/looseness/short-circuit
®

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

´
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.
lZündkerzenstecker 3
lZündkerze 4
Nur USA und CDN
õNicht 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:
lSteckverbinder- und Kabel-
anschlüsse
Rost/Staub/Lockerheit/Kurz-
schluß ® Instand setzen
oder erneuern.
MOTORSTOPPSCHALTER “ENGI-
NE STOP” KONTROLLIEREN
1. Kontrollieren:
lMotorstoppschalter
(auf Durchgang)
Kein Durchgang bei gedrücktem
Schalter ® Erneuern.
Durchgang bei freigelassenem
Schalter ® Erneuern. Meßkabel (+) ®
schwarz/weiß 1
Meßkabel (–) ® schwarz 2
B/W
1 B
2 Meßge-
rät-
Einstel-
GE-
DRÜCKT
W ´ 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.
lCapuchon de bougie 3
lBougie 4
Pour les USA et le CDN
õExcepté 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:
lConnexion de coupleurs et fils
Rouille/poussière/jeu/court-cir-
cuit ® Réparer ou changer.
CONTROLE DU BOUTON
D’ARRET DU MOTEUR “ENGINE
STOP”
1. Vérifier:
lContinuité du bouton d’arrêt du
moteur “ENGINE STOP”
Pas de continuité lorsqu’enfoncé ®
Changer.
Continuité lorsque relâché ® Changer. Fil (+) de testeur ®
Fil noir/blanc 1
Fil (–) de testeur ® Fil noir 2
B/W
1B
2Position de
sélecteur
du testeur
EN-
FONCE
W ´ 1
RE-
LACHE
6 - 4PRUEBA 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.
lTapa de la bujía 3
lBujía 4
Para USA y CDN
õExcepto 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:
lConexión de acopladores y
cables
Oxido/Polvo/Flojedad/Corto-
circuito ® Reparar o reempla-
zar.
INSPECCIÓN DEL BOTÓN DE
PARADA DE MOTOR “ENGINE
STOP”
1. Inspeccionar:
lConducto 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)
W ´ 1
LIBRE

6 - 7
–+ELECTPS (THROTTLE POSITION SENSOR) SYSTEM
EC69000
TPS (THROTTLE POSITION SENSOR) SYSTEM
EC691000
INSPECTION STEPS
If the TPS will not operate, use the following inspection steps.
*marked: Refer to “IGNITION SYSTEM” section.
NOTE:
lRemove the following parts before inspection.
1) Seat
2) Fuel tank
lUse the following special tools in this inspection.
Check entire ignition
system for connection.Repair or replace.
Check TPS. TPS coil Replace.
*Check CDI magneto. Source coil Replace.
Check CDI unit.TPS input
voltageReplace.
Pocket tester:
YU-03112/90890-03112Inductive tachometer:
YU-8036-1
Engine tachometer:
90890-03113
No good
No good
No good
No good
OK
OK
OK

6 - 10
–+ELECTPS (THROTTLE POSITION SENSOR) SYSTEM
6. Adjust:
lTPS coil resistance at idle speed
Adjustment steps:
Adjust the angle of the TPS 1 to obtain
the resistance calculated (example: 650 ~
750 W)
Tester (+) lead ® Yellow lead 2
Tester (–) lead ® Black lead 3
7. Tighten:
lScrew (TPS) 1
8. Install:
lTPS coupler
EC694000
TPS INPUT VOLTAGE INSPECTION
1. Disconnect the TPS coupler.
2. Start the engine.
3. Inspect:
lTPS input voltage
Out of specification ® Replace the CDI
unit.
Tester (+) lead ® Blue lead 1
Tester (–) lead ® Black lead 2
TPS input
voltageTester selector
position
4 ~ 6 V DCV-20

7 - 1
TUN

EC700000
TUNING
EC710000
ENGINE
Carburetor setting
l
The air/fuel mixture will vary depending on
atmospheric conditions. Therefore, it is nec-
essary to take into consideration the air pres-
sure, ambient temperature, humidity, etc.,
when adjusting the carburetor.
l
Perform a test run to check for proper engine
performance (e.g., throttle response) and
spark plug(-s) discoloration or fouling. Use
these readings to determine the best possi-
ble carburetor setting.
NOTE:

It is recommended to keep a record of all car-
buretor settings and external conditions (e.g.,
atmospheric conditions, track/surface condi-
tions, lap times) to make future carburetor set-
ting easier.
WARNING

l
The carburetor is a part of the fuel line.
Therefore, be sure to install it in a well-
ventilated area, away from flammable
objects and any sources of fire.
l
Never look into the carburetor intake.
Flames may shoot out from the pipe if the
engine backfires while it is being started.
Gasoline may be discharged from the
accelerator pump nozzle when the carbu-
retor has been removed.
CAUTION:

l
The carburetor is extremely sensitive to
foreign matter (dirt, sand, water, etc.).
During installation, do not allow foreign
matter to get into the carburetor.
l
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.
l
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.
SETTING
7

7 - 4
TUN

SETTING
Main jet adjustment
The richness of the air-fuel mixture at full throt-
tle can be set by changing the main jet
1
.
If the air-fuel mixture is too rich or too lean, the
engine power will drop, resulting in poor accel-
eration.
Effects of changing the main jet (reference)

Idle
õ
Fully open
Standard main jet #165
1/4 1/2 3/4
+10%
#165
–10% AB
#175
#155

Pilot screw adjustment
The richness of the air-fuel mixture with the
throttle fully closed to 1/8 open can be set by
turning the pilot screw
1
. Turning in the pilot
screw will make the mixture lean at low
speeds, and turning it out will enrich it.
* Except for USA
NOTE:

The pilot screw is set at the factory, there is no
need to adjust it.
If the idling speed fluctuates, turn the pilot
screw only 1/2 of a turn in either direction.
Effects of adjusting the pilot screw (refer-
ence)

Idle
õ
Fully open
1
2-1/8 turns out
2
1-1/8 turns out
3
1-5/8 turns out
Standard pilot
screw position1-5/8 turns out
* 1-1/2 turns out
(for reference only)
1/4 1/2 3/4
+5%
–5% AB
1
23

7 - 5
TUN

SETTING
Pilot jet adjustment
The richness of the air-fuel mixture with the
throttle open 1/4 or less can be set by adjust-
ing the pilot jet.
If the engine breathes hard when you start
opening the throttle, the air-fuel mixture is too
rich and should be made leaner.
Effects of adjusting the pilot jet (reference)

Idle
õ
Fully open
Jet needle groove position adjustment
Adjusting the jet needle
1
position affects the
acceleration when the throttle is 1/4 to 1/2 open.
1. Too rich at intermediate speeds
Rough engine operation is felt and the
engine will not pick up speed smoothly. In
this case, step up the jet needle clip by
one groove and move down the needle to
lean out the mixture.
2. Too lean at intermediate speeds
The engine breathes hard and will not
pick up speed quickly.
Step down the jet needle clip by one
groove and move up the needle to enrich
the mixture.
* Except for USA
Effects of changing the jet needle groove
position (reference)

Idle
õ
Fully open
1
No.4 groove
2
No.2 groove
3No.3 groove
Standard pilot jet #42
Standard clip positionNo.3 groove
*No.4 groove
1/4 1/2 3/4
+5%
–5%
#45
#40#42

õ
1/4 1/2 3/4
+10%
–10% AB
1
23