Robb a 276/400R was fitted to a WD Matchless G3, and originally was fitted with a 276B/1J. The 276/400R is a body supplied to replace the worn out 276B/1J, It has a one inch choke so same as a BSA M20 carb body.
I used to get a lot of guys ring me with a list of a dozen or so carb numbers that they wanted to know what they fitted so they could sell them quicker at Swapmeets (Autojumbles) as unless they wrote it on most guys did not know what carb they were chasing for their project.
John have you ever come across this? Pictures of a new carb and this war-time document were kindly given to me by Amal UK (Burlen fuels) and indicates some modifications to the G3 carb. The drip hole is machined into the flange and deleted from the jet block. My carb already had the drip hole in the flange when Martyn refurbed it but he wasn't aware of the requirement to block off the bleed hole in the jet block, which he duly did. Mine is stamped 276B/1J....I think it has to do with stopping the carb flooding into the cylinder? Ron
Hi Ron, I have only seen one body with that bleed hole and machining and thought it had been machined by some clever enthusiast. Interesting what can be found in UK if you go looking. I will be on a mission now to check the Matchless motorbikes that I know off to see if they have that drilling.