Amal carb spec

[richard norris]

Is there a book or photocopy of specs for the different varieties of each model of pre-war carbs? I never realised quite how many different specs there were and would quite like to know what I should have for my bikes.

[chris wastell]

I think there’s one on eBay at t he moment 😮

[richard norris]

I must need new specs, can only find tuning guides.

[Ian Parsons]

My 1937 and 1949 Books of the Scott lists jet sizes for the various models of Scotts. I can email you a copy of the relevant pages. Earlier copies of the Book seem to refer one to the carburetor manufacturer’s handbook.

[richard norris]

Thanks Ian, was a general enquiry really, there seem to be many different models of type 276 and 289 – I was wondering whether they all have slightly different jet blocks or internal drillings or whether the model numbers simply refer to jet, needle and slide specs. I.e will any carb body and jet block of suitable bore do or not?

[BRIAN MARSHALL]

The earlier versions of the Scott-Amal type 6 and type 29 had an external primary inlet system, with four external holes in the side of the body. The specifying dept. of the armed forces vehicle procurement did not like this feature, and sensibly insisted that ALL air entering the carb could be filtered. The carbs were therefore modified, with an internal primary air inlet just inside the main air inlet, near the bellmouth retaining thread. Jet blocks are totally different between the two types, and not interchangeable. I think that this major change occured somewhere around 1938. Jet sizes stated prewar and postwar are no longer relevant because petrol is totally different. For instance if it stated a 170 main jet, you will need a 190 or 200. A type 29, as fitted to the 1939 Clubman Special will need a 210 or 220 main jet if the engine is still in its original ‘specially tuned’ specification, and 596cc.
Brian

[BRIAN MARSHALL]

I should also have said that many parts are interchangeable between types 6 and 29, and between earlier and later versions, including jets, complete float chambers, throttle slide and air slide return springs, cable adjusters, throttle stop screws, and primary air screws. Jet blocks, jet tubes, and the bottom float chamber banjo bolt are NOT interchangeable, the latter because the type 29 jet tube is longer, and the main jet will be masked by the shorter banjo bolt of the type 6.
Brian

[richard norris]

Thanks Brian, very helpful, totally agree about jet sizes. Happy New Year everyone.

[PaulR]

I have possibly the info you request, but not the ability to wire it to you. However once the

family return from skiing they will advise the feasibility to furnish this Amal text to you.

All good wishes from Scott-land for 2016

[richard norris]

Thanks Paul, look forward to hearing from you, have a great time skiing and Happy New Year.

[Author]

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