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Function
This model Is cquipsed with "constant
velocity ' (CV) carburetor mounted on rubber
intake manifolds
1, Air flow through tho venturi is con
trolled by @ throttle slide (vacuum
piston). The slide is raised and lowered
by engine vacuum rether than 3 cable
linkee directly to the throttie grip. This
type
of
carburetcr
compensates
automatically for atmospheric pressure
changes such as those encountered
b
whan riding at high altitudes
2, With a conventional one-position star-
ter jet, the air-fuel ratio remains the
same as that required to start the
engine (despite the fact that the engins
temperature rises gradually) until the
'engine operating temperature rises to
the point at which use of the starter jet
is no longer necessary. In other words,
beyond s certain paint. the air-fuel mix
ture is too rich until the engine operat-
ing temperature rises to = certain point
and the starter jet is shut off.
The newly-adopted two-pesition type
starter jet is designed to supply @ mix-
ture of more appropriate richness by
switching from one js: to another.
a. Routes
of fuel and air
The
fuel
supplied
from
the
ficat
'chamber (1) passes through (2) an
metered by (3). Air is supplied from the
air chamber in the float cnamber
and
flaws through (4), It is then mixed with
the metered fuel, The resultant mixture
passes through (8) and tlows into the
two-posizion starter jet (6), where it is
further mixed with air supplied from the
diaphragm (7) and stroaams into the
throttle bore out of (6).
Operation of two-position starter jet
Full-open
To start a cold engine, a rich mixture is
required, To supply @ rich mixture,
pull
the starter lever and the way out so that
the needle regulating the fuvl flow 1 set
free end the flow rate of incoming fuel is
increased to a maximum. The fuel is
mixed with the air supplied fom the
digphragm lower chamber, and thus a
rich mixture is produced.
'Dashes enerohamesr 2 uropen
g Thvette sore
Kolf open:
Aiter starting, that is, during warm-up, a
slightly rich mixture is requirod. Push
back the starter lover half-way so that
the fuel flow is reducec by the needle.
The fuel is mixed with the air from the
diophragm lower chamber, and thus a
slightly nich moxture 1s produced.
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