2004 YAMAHA YZ85 stop start

3 - 14
INSP
ADJ
PILOT AIR SCREW ADJUSTMENT
1. Adjust:

Pilot air screw 1
Adjustment steps:
NOTE:
To optimize the fuel flow at a smaller throttle
opening, each machine’s pilot air screw has
been individually set at the factory. Before
adjusting the pilot air screw, turn it in fully and
count the number of turns. Record this num-
ber as the factory-set number of turns out.

Turn in the pilot air screw until it is lightly
seated.

Turn out the pilot air screw by the speci-
fied number of turns.
Pilot air screw:
2 turns out (example)
5PA30230
ENGINE IDLING SPEED ADJUSTMENT
1. Start the engine and thoroughly warm it up.
2. Adjust:

Engine idling speed
Adjustment steps:

Turn the throttle stop screw 1 until the
engine runs at the lowest possible speed.
To increase idle speed → Turn the throt-
tle stop screw 1 in a.
To decrease idle speed → Turn the throt-
tle stop screw 1 out b.
5PA30240
EXHAUST PIPE INSPECTION
1. Inspect:

O-ring 1
Damage → Replace.
NOTE:
Install the O-rings with their depressed a fac-
ing inward.
5PA30250
PILOT AIR SCREW ADJUSTMENT/ENGINE IDLING
SPEED ADJUSTMENT/EXHAUST PIPE INSPECTION

4 - 7
ENGCARBURETOR AND REED VALVE
EC468000
CARBURETOR DISASSEMBLY
5PA40100
Extent of removal:
1 Carburetor disassembly
Extent of removal Order Part name Q’ty Remarks
CARBURETOR DISASSEMBLY
1Mixing chamber top 1
2Throttle valve 1 Refer to “REMOVAL POINTS”.
3Jet needle 1
4Float chamber 1
5Float pin 1
6Float 1
7Main jet 1
8Main nozzle holder 1
9Main nozzle 1
0Pilot jet 1
AStarter plunger 1
BThrottle stop screw 1
CPilot air screw 1 Refer to “REMOVAL POINTS”.
1

4 - 12
ENGCARBURETOR AND REED VALVE
Carburetor
1. Install:

Pilot air screw 1

Throttle stop screw 2
Note the following installation points:

Turn in the pilot air screw until it is lightly
seated.

Turn out the pilot air screw by the number
of turns recorded before removing.
Pilot air screw:
2 turns out (example)
5PA40260
2. Install:

Starter plunger 1
5PA40270
3. Install:

Pilot jet 1

Main nozzle 2

Main nozzle holder 3

Main jet 4
NOTE:
Install the main nozzle with its chamfered side
a facing the carburetor.
5PA40280
4. Install:

Needle valve 1

Float 2

Float pin 3
NOTE:

After installing the needle valve to the float,
install them to the carburetor.

Check the float for smooth movement.
5PA40290

6 - 3
–+ELECIGNITION SYSTEM
SPARK GAP TEST
1. Disconnect the spark plug cap from spark
plug.
2. Connect the dynamic spark tester 1 (igni-
tion checker 2) as shown.

Spark plug cap 3

Spark plug 4
ÈFor USA and CDN
ÉExcept for USA and CDN
3. Kick the kickstarter crank.
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)
È
5PA60030
É
5PA60040
EC624000
COUPLERS AND LEADS CONNECTION
INSPECTION
1. Check:

Couplers and leads connection
Rust/dust/looseness/short-circuit → Repair
or replace.
ENGINE STOP SWITCH INSPECTION
1. Inspect:

Engine stop switch conduct
No continuous while being pushed → Replace.
Continuous while being freed → Replace. Tester (+) lead
→ Black/White lead
1
Tester (–) lead
→ Black lead
2
B/W
1B
2Tester selec-
tor position
PUSH IN
Ω
× 1
FREE
5PA60050

–+ELEC
SYSTEME D’ALLUMAGE
ZÜNDANLAGE
TEST DE LA LONGUEUR D’ETINCELLE
1. Déconnecter le capuchon de bougie.
2. Connecter le testeur dynamique d’étincelle 1
(contrôleur d’allumage 2) comme indiqué.

Capuchon de bougie 3

Bougie 4
ÈUSA et CDN
ÉSauf pour USA et CDN
3. Actionner le kick.
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 USA et CDN)
Longueur d’étincelle minimum:
6,0 mm (0,24 in)
CONTROLE DES CONNEXIONS DES
COUPLEURS ET DES FILS
1. Contrôler:

Connexion des coupleurs et des fils
Rouille/poussière/jeu/court-circuit → Réparer
ou remplacer.
CONTROLE DU COUPE-CIRCUIT DU
MOTEUR
1. Contrôler:

Continuité du coupe-circuit du moteur
Pas de continuité lorsque enfoncé → Remplacer.
Continuité lorsque relâché → Remplacer. Fil (+) du multimètre →
fil noir/blanc 1

Fil (–) du multimètre →
fil noir 2

B/W
1B
2Position du
sélecteur du
multimètre
ENFON-
CE
Ω
×
1
RELA-
CHE
ZÜNDFUNKENSTRECKE KONTROLLIEREN
1. Den Zündkerzenstecker von der Zünd-
kerze abziehen.
2. Den Zündfunkenstreckentester 1 (bzw.
Zündprüfer 2) wie abgebildet anschließen.

Zündkerzenstecker 3

Zündkerze 4
ÈNur USA und CDN
ÉNicht USA und CDN
3. Den Motor mit dem Kickstarter durchdre-
hen.
4. Die Zündfunkenstrecke kontrollieren.
5. Den Motor starten und die Zündfunken-
strecke vergrößern, bis es zu Fehlzündun-
gen kommt. (nur USA und CDN)
Min. Zündfunkenstrecke:
6,0 mm (0,24 in)
STECKVERBINDER UND
KABELANSCHLÜSSE KONTROLLIEREN
1. Kontrollieren:

Steckverbinder und Kabelanschlüsse
Rost/Staub/Lockerheit/Kurzschluß →
Instand setzen oder erneuern.
MOTORSTOPPSCHALTER
KONTROLLIEREN
1. Kontrollieren:

Motorstoppschalter (auf Durchgang)
Kein Durchgang bei gedrücktem Schalter →
Erneuern.
Durchgang bei losgelassenem Schalter →
Erneuern.Meßkabel (+)
→ Schwarz/Weiß
1
Meßkabel (–)
→ Schwarz
2
B/W
1B
2Meßgerät-Ein-
stellung
GE-
DRÜCKT
Ω
× 1
FREI
6 - 3