Loading ...
Loading ...
Loading ...
Adjustments for Competition 129
Carburetor Adjustment & Tuning Tips
Accelerator Pump Circuit
The accelerator pump circuit operates when the
throttle is opened. As the throttle valve (1) opens,
the pump rod (2) depress the diaphragm (3). At this
time, the inlet check valve (4) is shut resulting in a
sharp increase in pressure in the pump chamber
(5). The outlet check valve (6) then opens,
supplying fuel to the main bore via the accelerator
nozzle (7).
Slow Circuit
Fuel is metered by the slow jet (1) and mixed with
air from the air passage (2). The mixture enters the
venturi through the bypass (3) and pilot outlet (4)
that has been metered by the pilot screw (5).
Main Circuit
Fuel is metered by the main jet (1), jet needle (2)
and needle jet (3). It is then mixed with air coming
from the air jet (4) and enters the venturi past the
needle jet.
Baffle Plate
The baffle plate (5) prevents foaming of fuel or
abnormal fuel level around the main jet.
Float Bowl
The float (6) and float valve (7) operate to maintain
a constant level of fuel in the float bowl.
(1) throttle valve (5) pump chamber
(2) pump rod (6) outlet check valve
(3) diaphragm (7) accelerator nozzle
(4) inlet check valve
(3)
(1)
(7)
(6)
(2)
(5)
(4)
(1) slow jet (4) pilot outlet
(2) air passage (5) pilot screw
(3) bypass
(3)
(2)
(1)
(5)
(4)
(1) main jet (5) baffle plate
(2) jet needle (6) float
(3) needle jet (7) float valve
(4) air jet
(2)
(4)
(7)
(6)
(5)
(1)
(3)
Loading ...
Loading ...
Loading ...