Diaphragm And Piston Operation - Suzuki GS1100G 1982 Service Manual

5-5 FUEL AND LUBRICATION SYSTEM
DIAPHRAGM AND PISTON OPERATION
The carburetor is of a variable-venturi type, whose venturi cross section area is increased or decreased
automatically
by the
piston
according
to
the vacuum present on the downstream side
of
the venturi.
Vacuum
is admitted into the diaphragm chamber through
an
orifice provided in
the
piston.
Rising
vacuum overcomes the spring force, causing the piston to rise to increase the said area and thus
to prevent the air velocity from increasing. Therefore, air velocity in the venturi passage is kept relatively
constant for
improved fuel atomization and for securing an optimum ratio of fuel to air in the mixture.