Adjusting The Idle Speed - Beta RR 390 2017 Mode D'emploi

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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 specifications on page
23).
• Warm up the engine.
•Turn adjusting knob 1 to obtain the standard idle speed (1500-1600 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 anticlockwise
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 con-
siderably, 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 adjusting screw
approximately 1/4 of a turn clockwise from the ideal setting.
Refer to the specifications carburetor or refer website www.betamotor.com.

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 knob 1 and mixture adjusting
screw 2. The adjusting knob regulates
the base position of the throttle valve. By
turning the knob clockwise increases the
rotation speed and counter-clockwise to
lower it. The mixture control screw adjusts
the amount of the mixed fuel with air for
the idle speed. Rotating the screw clock-
wise decreases the quantity of fuel (lean
mixture); rotating in anticlockwise increases
the quantity of fuel (rich mixture).
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GB