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Technical Info > Amal Carburettors > Monobloc 
Amal Monobloc carburettor, front

Monobloc Range

Amal logo Amal Monobloc carburettor, rear

Introduced by Amal in 1955 to replace the Type 6 carburettor. There are currently the 376 (15/16", 1", 1&1/16" sizes) & 389 (1&1/8", 1&5/32", 1&3/16" sizes) series available, in left hand versions only. A 376 1&1/16" carb with a "chopped" float bowl is available. This allows for twin carbs to be mounted closely alongside on parallel port heads.

When ordering parts we will need to know the size of your carburettor. An identification number will be appear on the body e.g. 376/--, 389/--. This designates the body size. there is also a 689 version which is a right hand 389 body. To determine the bore size it should be measured at the mounting flange. Carburettors are supplied jetted to suit the majority of applications. Separate jets & slides are available for fine tuning.

A good range of parts is available for these carburettors from British Spares. A sample list of applications is shown below for your reference.

The information given below is intended as a guide only, final settings required may vary due to local fuels etc.
Triumph Part Number Size mm Main Jet Pilot Jet Slide No. Needle Pos. Needle Jet
T100 1955-59 376/15 1&5/16" 220 25 3.5 4 106
T100SS 1961-65, T100/R/C 1966, T100S/C 1967 376/16 1" 190 25 3.5 3 106
TR6 1956-63 376/17 1&1/16" 250 25 3.5 3 106
T120 1964-67, T120R 1966 389/18 1&1/8" 260 25 3 3 106
6T 1963-66 376/17 1&1/16" 230 25 4 4 106
Norton              
99 1956-62, 99 (twin carbs) 1959-62, 99SS 61-62 376/17 1&1/16" 250 25 3 3 106
650 1961-63, 650 De Luxe 389/18 1&1/8" 320 25 3 2 106
750 Atlas 1962-66 376/17 1&1/16" 400 20 3.5 4 106
750 Atlas 1963-64, 1966 389/18 1&1/8" 420 20 3 3 106
750 Atlas 1965 & 1966 export 389/18 1&1/8" 350 20 3 3 106
BSA              
B31 1955-59 (without filter) 376/16 1" 260 30 3.5 2 106
B31 1956-57 (with filter), B31 export 58-59 376/16 1" 200 30 3.5 2 106
B33 1955-57, B33 home 1958-60 376/17 1&1/16" 260 25 3.5 3 106
A10 1955-57 376/17 1&1/16" 240 25 4 3 106
A50 USA 1963-67 376/16 1" 260 25 3.5 3 106
A65 1962, 1964-65 389/18 1&1/8" 300 25 3.5 3 106

Much of the above information has been taken from the restoration series of publications
by Roy Bacon, which are available from British Spares. For more information
click here