2002 YAMAHA WR 250F stop start

3 - 5
INSP
ADJ
EC350000
ENGINE
EC351011
COOLANT LEVEL INSPECTION
WARNING
Do not remove the radiator cap 1, drain
bolt and hoses when the engine and radia-
tor are hot. Scalding hot fluid and steam
may be blown out under pressure, which
could cause serious injury.
When the engine has cooled, place a thick
towel over the radiator cap, slowly rotate
the cap counterclockwise to the detent.
This procedure allows any residual pres-
sure to escape. When the hissing sound
has stopped, press down on the cap while
turning counterclockwise and remove it.
CAUTION:
Hard water or salt water is harmful to the
engine parts. You may use distilled water, if
you can’t get soft water.
1. Place the machine on a level place, and
hold it in an upright position.
2. Inspect:
Coolant level
Coolant level should be between the
maximum a and minimum b marks.
Coolant level is below the “LOW” level
line → Add soft water (tap water) up to
the proper level.
3. Start the engine and let it warm up for
several minutes.
4. Turn off the engine and check the coolant
level again.
NOTE:
Before checking the coolant level, wait a few
minutes until the coolant settles.
LOWFULLCOOLANT
a
b
COOLANT REPLACEMENT
WARNING
Do not remove the radiator cap when the
engine is hot.
ENGINE/COOLANT LEVEL INSPECTION/
COOLANT REPLACEMENT

3 - 12
INSP
ADJ
AIR FILTER CLEANING
2. Adjust:
Decompression lever free play
Adjustment steps:
Loosen the locknut 1.
Turn the adjuster 2 in or out until the
adjustment is suitable.
Tighten the locknut.
CAUTION:
After the adjustment, start the engine
and make sure that the engine does not
stop when the handlebar is turned fully
both ways. If the decompression cable is
too tense, the engine will stop by the
decompression system.
AIR FILTER CLEANING
NOTE:
Proper air filter maintenance is the biggest key
to preventing premature engine wear and
damage.
CAUTION:
Never run the engine without the air filter
element in place; this would allow dirt and
dust to enter the engine and cause rapid
wear and possible engine damage.
1. Remove:
Seat
2. Disconnect:
Taillight lead connectors 1
3. Remove:
Air filter case cover 2
4. Remove:
Fitting bolt 1
Washer 2
Air filter element 3
Air filter guide 4

INSP
ADJ
CHANGEMENT DE L’HUILE DE MOTEUR
MOTORÖL WECHSELN
SOSTITUZIONE DELL’OLIO MOTORE
MOTORÖL WECHSELN
1. Den Motor starten, mehrere
Minuten warmlaufen lassen,
und dann ausschalten und
fünf Minuten warten.
2. Die Maschine auf ebenem Ort
abstellen und auf dem Motor
aufbocken.
3. Einen geeigneten Behälter un-
ter den Motor stellen.
4. Demontieren:
Öltankdeckel 1
Rahmen des Ölablaufstop-
fens 2
Kurbelwellen-Ölablaufstop-
fen 3
Ölfilterelement-Ablaufstop-
fen 4
Das Kurbelgehäuse und den
Öltank (Rahmen) leerlaufen
lassen.
5. Demontieren:
Unterer Motorbügel
Ölschlauchklammer 1
Steckschraube (Öl-
schlauch) 2
Ölschlauch 3
Ölsieb (Rahmen) 4
6. Kontrollieren:
Ölsieb (Rahmen)
Verstopft → Ausblasen. CHANGEMENT DE L’HUILE DE
MOTEUR
1. Mettre le moteur en marche, le
faire chauffer pendant quelques
minutes, puis le couper et atten-
dre cinq minutes.
2. Placer le véhicule sur un plan
horizontal et le dresser à la verti-
cale en plaçant un support adé-
quat sous le moteur.
3. Déposer un récipient adéquat
sous le moteur.
4. Déposer:
Bouchon du réservoir d’huile
1
Boulon de vidange d’huile au
cadre 2
Boulon de vidange d’huile de
carter 3
Boulon de vidange d’élément
de filtre à huile 4
Vidanger l’huile du carter
moteur et du réservoir d’huile
(cadre).
5. Déposer:
Support inférieur de moteur
Bride de durit d’huile 1
Boulon (durit d’huile) 2
Durit d’huile 3
Crépine d’huile (cadre) 4
6. Vérifier:
Crépine d’huile (cadre)
Bouché → Passer à l’air com-
primé.SOSTITUZIONE DELL’OLIO
MOTORE
1. Avviare il motore, riscaldarlo per
alcuni minuti e quindi spegnerlo
ed attendere cinque minuti.
2. Posizionare il veicolo su una
superficie piana e tenerlo in posi-
zione eretta utilizzando il caval-
letto apposito posto sotto al
motore.
3. Posizionare un contenitore ido-
neo sotto al motore.
4. Rimuovere:
Tappo del serbatoio dell’olio
1
Bullone di scarico dell’olio del
telaio 2
Bullone di scarico dell’olio del
carter 3
Bullone di scarico elemento fil-
trante 4
Scaricare l’olio dal carter e dal
serbatoio dell’olio (telaio).
5. Rimuovere:
Staffa motore inferiore
Fascetta fermatubo dell’olio 1
Bullone (tubo flessibile
dell’olio) 2
Tubo flessibile dell’olio 3
Filtro dell’olio (telaio) 4
6. Ispezionare:
Filtro dell’olio (telaio)
Intasato → Pulire con aria.
3 - 16

3 - 19
INSP
ADJ
ENGINE IDLING SPEED ADJUSTMENT
1. Start the engine and thoroughly warm it
up.
2. Attach:
Inductive tachometer
To spark plug lead.
3. Adjust:
Engine idling 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 throt-
tle stop screw 1 in a.
To decrease idle speed → Turn the throt-
tle stop screw 1 out b.
Inductive tachometer:
YU-8036-B
Engine tachometer:
90890-03113
Engine idling speed:
1,800 ~ 2,100 r/min
VALVE CLEARANCE INSPECTION AND
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 CHAP-
TER 4.
2. Drain:
Coolant
Refer to “COOLANT REPLACEMENT”
section.
ENGINE IDLING SPEED ADJUSTMENT/
VALVE CLEARANCE INSPECTION AND ADJUSTMENT

4 - 16
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
* For EUROPE
** For CDN, ZA, AUS and NZNote 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:
2 turns out
* 1 turn out
** 1-1/8 turns out
(example)
13. Install:
O-ring
Leak jet 1
Float chamber 2
Bolt (float chamber) 3
Cable holder (throttle stop screw cable)
4
Hose holder (carburetor breather hose)
5

6 - 4
–+ELEC

IGNITION SYSTEM
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 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)
Å
ı

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
1
B
2
Tester selec-
tor position
PUSH IN
Ω

×
1
FREE

–+ELEC
SYSTEME D’ALLUMAGE
ZÜNDANLAGE
IMPIANTO DI ACCENSIONE
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
KONTROLLIEREN
1. Kontrollieren:
Motorstoppschalter
(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
Ω × 1
FREI
TEST DE LA LONGUEUR D’ETIN-
CELLE 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 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. (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 Remplacer.
CONTROLE DU COUPE-CIRCUIT
DU MOTEUR
1. Vérifier:
Continuité du coupe-circuit du
moteur
Pas de continuité lorsqu’enfoncé →
Remplacer.
Continuité lorsque relâché → Rempla-
cer.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
Test della distanza tra gli elettrodi
1. Staccare il cappuccio della can-
dela.
2. Collegare il tester della dinami-
cità della scintilla 1 (tester
dell’accensione 2) come illu-
strato.
Cappuccio della candela 3
Candela 4
ÅPer USA e CDN
ıTranne USA e CDN
3. Agire sulla pedivella di avvia-
mento.
4. Controllare la distanza tra gli
elettrodi.
5. Avviare il motore ed aumentare
la distanza tra gli elettrodi fino a
che non si verifica uno scatto a
vuoto. (Solo per USA e CDN)
Distanza minima tra gli
elettrodi:
6,0 mm (0,24 in)
ISPEZIONE DEI COLLEGAMENTI
DEGLI ACCOPPIATORI E DEI
CAVI
1. Controllare:
Collegamento degli accoppia-
tori e dei cavi
Ruggine/polvere/allentamento/
cortocircuito → Riparare o
sostituire.
ISPEZIONE DELL’INTERRUT-
TORE DI ARRESTO DEL MOTORE
1. Ispezionare:
Conduzione interruttore di
arresto motore
Assenza di continuità se premuto →
Sostituire.
Continuità se rilasciato→ Sostituire. Conduttore (+) del tester →
Conduttore nero/bianco 1
Conduttore (–) del tester →
Conduttore nero 2
B/W
1B
2Posizione
selettore
tester
PRE-
MUTO
Ω × 1
RILA-
SCIATO

6 - 11
–+ELEC
9. Tighten:
Screw (throttle position sensor) 1
NOTE:
Tighten the screws (throttle position sensor)
using the T20 bit (tamper resistant fastener
type).
10. Stop the engine.
THROTTLE POSITION SENSOR INPUT
VOLTAGE INSPECTION
1. Disconnect the throttle position sensor
coupler.
2. Start the engine.
3. Inspect:
Throttle position sensor input voltage
Out of specification → Replace the CDI
unit.
Tester (+) lead → Blue lead 1
Tester (–) lead → Black/Blue lead 2
Throttle posi-
tion sensor
input voltageTester selector
position
4 ~ 6 V DCV-20
THROTTLE POSITION SENSOR SYSTEM