3
CHECKS AND MAINTENANCE
52
GB
CARBURETTOR - ADJUSTING THE IDLE
SPEED
Engine starting is strongly affected by the
idle speed adjustment. In other words, an
engine whose slow running is properly
adjusted is easier to start than an engine
with an unsuitably tuned up engine.
The idle speed is adjusted by means of
adjusting wheel 1 and mixture adjusting
screw 2. The adjusting wheel regulates the
idling mixture, which reaches the engine
through the idling system. Rotating the
wheel clockwise decreases the quantity of
fuel (lean mixture); rotating it anticlockwise
increases the quantity of fuel (rich mixture).
To properly adjust the idle speed, follow these steps:
•Turn in mixture adjusting screw 2 until it stops, then turn it until you obtain the basic
adjustment recommended by BETAMOTOR (see engine specifi cations on page 25).
•Warm up the engine.
•Turn adjusting wheel 1 to obtain the standard idle speed (1400-1500 rpm).
•Slowly turn mixture adjusting screw 2 clockwise until the idle speed begins to
lower. Remember this position, then slowly turn the mixture adjusting screw anti-
clockwise until the engine speed lowers again. Determine the point between the
two positions where the highest idle speed is obtained. Should the engine speed
increase considerably, decrease the engine speed to the standard level and repeat
the above procedure. If you make a markedly sporting use of your vehicle, which
increases the heating of the engine, choose a leaner mixture by turning the adjust-
ing screw approximately 1/4 of a turn clockwise from the ideal setting.
Refer to the specifi cations carburetor or refer website www.betamotor.com.
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