Main System - Suzuki GS850G Service Manual

MAIN SYSTEM
As throttle valve is opened, engine speed rises,
and this
increases vacuum in the venturi. Consequently the
piston valve moves upward.
Meanwhile, the fuel in float chamber is metered by main jet, and the metered
fuel enters needle jet, in
which it mixes with the air admitted through main air
jet
;to
form an emulsion.
The emulsified fuel
then
passes through the clearance between needle jet and jet needle and is discharged
into the venturi, in which it meets main air stream drawn by the engine.
Mixture proportioning is accomplished in needle jet; the clearance through which the emulsified fuel
must flow is either large or small depending u'ltirnetely on throttle position.
@
Air
@
FuelIAir Mixture
Fuel