Brown & Barlow carburettor 123-5 for EW 350

[Edin]

Hej all.
Can someone please help and inform me about correct hole diameter in the main jet on  B&B 123-5 carburettor,- fitted to an EW 350.  I think the main jet on my 1926 EW 350 ccm Sport,- is much to big.
I would be gratefull for information about this measures.
Regards Edin DK

[Alan]

To quote directly from the "Running Instructions for EW Model": Douglas Motor Cycles.....The carburettor ( B&B) is fitted with two jets- a pilot and a main, the size of main jet may vary slightly with different engines and varying conditions, but generally speaking a 75 Jet should be found correct.

[cardan]

(My little book says that a B&B 75 jet is about 0.029" diameter.)

Leon

[Doug]

Edin,

There were two possible  types of 123-5 B&B carbies being fitted to 350EWs at this time. One was the gauze type and the other had a taper needle. A different style main jet was fitted to each, and the default jet size may have differed depending on type. As Leon mentioned, the EW handbook states a #75 main jet. Since the latest handbook I have dates for the 1926 models, I am pretty sure this is for the gauze or needle-less carb.

The needle jet carb seems to have become standard fitting on the 1929 600EW models, but I am not sure if that was the case, or when, or if ever, the 350EW got the same. Also a Sports EW may have had the needle jet carb while the standard 350EW did not. in any event, I have not seen any clear information what the default main jet size would be for a 350EW fitted with the taper needle main jet.

Doug


[Change "1928" to "1929". 26Mar13 -Doug]

[Edin]

Thanks to - Alan - Leon and Doug for reply and help ,- it is just what I needed.
Regards Edin DK