Hi if you knowlegeable carb guys can give an opinion on these images on my 276 carb, purchased in 2019 from Hitchcocks for my 1943 BSA WD M20.

1st set of images, running a Champion 86c, E10 Petrol, needle on 3rd groove, 170 main, 106 needle, air screw backed out i & 1/4 turns, plug image after a 20 mile non stop run at about 40mph.


Second set of images same as above but on NEEDLE GROOVE 4.


any advice appreciated.
JohnB

Hi John
I’ll try get the photos I have of this carb loaded here so you can perhaps make a call on what I have

Hoping my friend can use it on his June 39 K m20/21
Br
John

email (option): jonnyob1@googlemail.com

John has forwarded me some photos. It looks as if it has been boiled for half a century in a mixture of Castrol 'R' and Lynklife !

The body is clearly stamped 276/014R



It has the gusset under the inlet, and clearly the four radial drillings for use with a Type 76 jet block.



but, and this is probably the crux of the matter, it is bored via the inlet for use with the /R suffix jet block. To my mind, this can only be an owner-modified 276.



Incidentally, despite what Amal published after the war, the Norton WD16H was being fitted with a 276/011 carb as early as December 1936. This was with the Norton type jet block though, and not the /R type.

Thanks Rik
Once we get it apart here - we can check the block for type fitted -
Found out some new info again - which is always good

Br
Jo’b

email (option): jonnyob1@googlemail.com

Yes it is a 276 that has been modified by having the four holes drilled probably to suit the 4 hole jetblock that was laying in his shed/barn.

Agree with John Parker, Body Stamping looks original and it has the large air passage hole in the inlet track as a 276. The 4 holes are drilled for a type 6 jet block and as a later 276 block is fitted the body holes will be blocked off with the 276 jet block so the carb would function ok.