Yamaha YZ250F(R) Owner's Service Manual page 76

ENGINE IDLING SPEED ADJUSTMENT/
VALVE CLEARANCE INSPECTION AND ADJUSTMENT
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:
1,900 ~ 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.
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INSP
ADJ