3-11
ENGINE
ADJUSTING THE VALVE
CLEARANCE
•
The valve clearance should be ad-
justed 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:
• Spark plug
• Cylinder head cover
Refer to "CAMSHAFTS" section
in the CHAPTER 4.
3. Remove:
• Timing mark accessing screw "1"
• Crankshaft end accessing screw
"2"
• O-ring
4. Check:
• Valve clearance
Out of specification
→
Adjust.
Checking steps:
a. Turn the crankshaft counterclock-
wise with a wrench.
b. Align the T.D.C. mark "a" on the
rotor with the align mark "b" on the
crankcase cover when piston is at
T.D.C. on compression stroke.
In order to be sure that the piston is at
Top Dead Center, the punch mark "c"
on the exhaust camshaft and the
punch mark "d" on the intake cam-
shaft must align with the cylinder
head surface, as shown in the illustra-
tion.
c. Measure the valve clearance "e"
using a feeler gauge "1".
Record the measured reading if the
clearance is incorrect.
5. Adjust:
• Valve clearance
Adjustment steps:
a. Remove the camshaft (intake and
exhaust).
Refer to "CAMSHAFTS" section
in the CHAPTER 4.
b. Remove the valve lifters "1" and
the pads "2".
•
Place a rag in the timing chain
space to prevent pads from falling
into the crankcase.
• Identity each valve lifter and pad
position very carefully so that they
can be reinstalled in their original
place.
c. Select the proper pad using the
pad selecting table.
The thickness "a" of each pad is indi-
cated in hundredths of millimeters on
the pad upper surface.
d. Round off the last digit of the in-
stalled pad number to the nearest
increment.
EXAMPLE:
Installed pad number = 148
Rounded off value = 150
Pads can only be selected in 0.05
mm increments.
e. Locate the rounded-off value and
the measured valve clearance in
the chart "PAD SELECTION TA-
BLE". The field where these two
coordinates intersect shows the
new pad number to use.
Valve clearance (cold):
Intake valve:
0.10–0.15 mm
(0.0039–0.0059 in)
Exhaust valve:
0.17–0.22 mm
(0.0067–0.0087 in)
Pad range
Pad Availabili-
ty: 25 incre-
ments
No.
120–
No.
240
1.20
mm–
2.40
mm
Pads are avail-
able in 0.05 mm
increments
Last digit of pad
number
Rounded valve
0, 1 or 2
0
4, 5 or 6
5
8 or 9
10
Содержание YZ250F(X)
Страница 2: ......
Страница 37: ...2 17 LUBRICATION DIAGRAMS 1 Crankshaft 2 Oil filter element 3 Oil tank 4 Oil hose A From oil pump ...
Страница 57: ...3 13 ENGINE INTAKE EXHAUST ...
Страница 108: ...4 41 OIL PUMP 15 Rotor housing 1 Order Part name Q ty Remarks ...
Страница 159: ...5 29 STEERING 9 Bearing race 2 Refer to removal section Order Part name Q ty Remarks ...
Страница 168: ...5 38 REAR SHOCK ABSORBER 12 Bearing 2 Refer to removal section Order Part name Q ty Remarks ...
Страница 243: ...3 13 MOTEUR ADMISSION ECHAPPEMENT ...
Страница 275: ...4 21 CULASSE 7 Carter de chaîne de distribution côté échappe ment 1 Ordre Nom de la pièce Qté Remarques ...
Страница 298: ...4 44 BALANCIER 5 Replier l onglet de la rondelle frein ...
Страница 300: ...4 46 POMPE A HUILE 14 Arbre d entraînement de pompe à huile 1 15 Boîtier du rotor 1 Ordre Nom de la pièce Qté Remarques ...
Страница 361: ...5 38 AMORTISSEUR ARRIERE 12 Roulement 2 Se reporter à la section de dépose Ordre Nom de la pièce Qté Remarques ...
Страница 384: ......
Страница 419: ...2 17 SCHMIERSYSTEM SCHAUBILDER 1 Kurbelwelle 2 Ölfiltereinsatz 3 Öltank 4 Ölschlauch A Von der Ölpumpe ...
Страница 439: ...3 13 MOTOR EINLASS AUSLASS ...
Страница 495: ...4 45 ÖLPUMPE 15 Rotorgehäuse 1 Reihenfolge Bauteil Anz Bemerkungen ...
Страница 555: ...5 38 FEDERBEIN 12 Lager 2 Siehe den Abschnitt zum Ausbau Reihenfolge Bauteil Anz Bemerkungen ...
Страница 578: ......
Страница 634: ...3 14 MOTORE ASPIRAZIONE SCARICO ...
Страница 685: ...4 40 ELEMENTO FILTRO OLIO E POMPA DELL ACQUA Applicare il grasso a base di sapone di litio sulla guarnizione circolare ...
Страница 688: ...4 43 EQUILIBRATORE 5 Piegare la linguetta della rondella di bloccaggio ...
Страница 690: ...4 45 POMPA DELL OLIO 15 Alloggiamento del rotore 1 Ordine Denominazione Quantità Osservazioni ...
Страница 774: ......
Страница 775: ......