Engine Maintenance and Modification Bradley Artigue

FIAT 124 Spider
Engine Maintenance + Modification
device on the primary (34 DMS/201) or secondary barrel (34 DMS 1/201 - 34 DMS
2/201): from bowl (17) the fuel metered by a calibrated bush (3) get mixed with the air
coming from calibrated orifice (4).
The mixture thus formed through duct (6) and calibrated bush (7) is drawn via duct (8) -
into the carburetor primary or secondary barrel during high speed running.
The figure also shows the device for differentiated opening of throttle valves. Upon
actuating throttles control lever (25) the tab (26) of the lever plate (22) fixed on primary
shaft (12) turns and the primary throttle (13) opens by an equivalent angle whilst the
secondary throttle (24) on spindle (23) remains closed.
Subsequently, tab (26) contacts the lug (27) of idle lever (21) which, by shifting the lever
(28), rotates the secondary spindle (23) until both throttles are simultaneously wide open.
The figure above also shows the device for gases aspiration from engine crankcase -
schemes A and B. It consists of a rotary blanking disc (31) driven by primary shaft (12)
which through groove (32) connects the tube (29) - conveying gases to be aspirated -
with the area downstream of primary throttle (13). Even with throttles in idle position,
conveyance of aspirated gases still takes place and is metered by the calibrated orifice
(30).
Figure 22: DMS Progression
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