2000 YAMAHA YZ426F stop start

3 - 15
INSP
ADJ
ENGINE OIL REPLACEMENT
5. Start the engine and let it warm up for
several minutes.
CAUTION:
When the oil tank is empty, never start the
engine.
6. Idle the engine more than 10 seconds
while keeping the motorcycle upright.
Then stop the engine and add the oil to
the maximum level.
7. Install:
lOil tank cap
ENGINE OIL REPLACEMENT
1. Start the engine and let it warm up for
several minutes.
2. Stop the engine and place an oil pan
under the drain bolt.
3. Remove:
lOil filler plug 1
lDrain bolt (with gasket) 2
lDrain bolt (with gasket) 3
lOil filter drain bolt (O-ring) 4
Drain the crankcase and oil tank
(frame) of its oil.
4. Remove:
lEngine skidplate
lEngine oil hose clamp 1
lEngine oil hose 2
lOil strainer (frame) 3
5. Clean:
lOil strainer (frame)

3 - 18
INSP
ADJIDLE SPEED ADJUSTMENT/
VALVE CLEARANCE ADJUSTMENT
EC35M021
IDLE SPEED ADJUSTMENT
1. Start the engine and thoroughly warm it
up.
2. Adjust:
lIdle speed
VALVE CLEARANCE ADJUSTMENT
NOTE:
lThe valve clearance should be adjusted
when the engine is cool to the touch.
lThe piston must be at Top Dead Center
(T.D.C.) on compression stroke to check or
adjust the valve clearance.
1. Remove:
lSeat
lSide covers
lAir scoops
lFuel tank
Refer to “SEAT, FUEL TANK AND SIDE
COVERS” section in the CHAPTER 4.
2. Drain:
lCoolant
Refer to “COOLANT REPLACEMENT”
section.
3. Remove:
lRADIATOR
Refer to “RADIATOR” section in the
CHAPTER 4.
lEngine stay (upper)
lCylinder head breather hose
lCylinder head cover
lSpark plug cap
Refer to “CYLINDER HEAD COVER”
section in the CHAPTER 4. Adjustment steps:
lAdjust the pilot screw.
Refer to “PILOT SCREW ADJUSTMENT”
section.
lTurn 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

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
ZÜNDFUNKENSTRECKE KONTROLLIEREN
1. Den Zündkerzenstecker von der Zünd-
kerze abziehen.
2. Den Zündfunkenstreckentester
1
(bzw.
2
) wie abgebildet anschließen.
l
Zündkerzenstecker
3

l
Zündkerze
4


Nur USA und CAN
õ
Nicht USA und CAN
3. Den Motor mit dem Kickstarter durchdre-
hen.
4. Die Zündfunkenstrecke kontrollieren.
5. Den Motor anlassen und die Zündfunken-
strecke vergrößern, bis es zu Fehlzün-
dungen kommt (nur USA und CAN).
Min. Zündfunkenstrecke
6,0 mm
MOTORSTOPPSCHALTER “ENGINE STOP”
KONTROLLIEREN
1. Kontrollieren:

l
Motorstoppschalter
(auf Durchgang)
Kein Durchgang bei gedrücktem Schalter
®
Erneuern.
Durchgang bei freigelassenem Schalter
®
Er-
neuern.
Meßkabel (+)
®
schwarz/weiß
1

Meßkabel (–)
®
schwarz
2

B/W
1
B
2
Meßgerät-
Einstellung
GE-
DRÜCK
W ´ 1
FREI
TEST DE L’INTERVALLE
D’ETINCELLEMENT D’ALLUMAGE
1. Déconnecter le capuchon de bougie de la
bougie.
2. Connecter le testeur dynamique d’étincelle 1
(testeur d’allumage 2) comme indiqué.
lCapuchon de bougie 3
lBougie 4
Pour les E.-U. et le Canada
õExcepté pour les E.-U. et le Canada
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.
(uniquement E.-U. et Canada)
Longueur d’étincelle minimum:
6,0 mm (0,24 in)
CONTROLE DES CONNEXIONS DE
COUPLEURS ET FILS
1. Contrôler:
lConnexion de coupleurs et fils
Rouille/poussière/jeu/court-circuit ®
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
1 B
2 Position de
sélecteur de
testeur
EN-
FONCE
W ´ 1
RE-
LACHE
6 - 4
STECKVERBINDER- UND KABEL-
ANSCHLÜSSE KONTROLLIEREN
1. Kontrollieren:
lSteckverbinder- und Kabelanschlüsse
Rost/Staub/Lockerheit/Kurzschluß ®
Instand setzen oder erneuern.

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 com-
ponents carefully. Even slight scratches,
bends or damage to carburetor 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