This is the base plug as fitted to the bottom of floatchambers on standard roadgoing Amal 276/289 type carburettors - it may also have been fitted to other Amal model types using seperate floatchambers - see detail listing for more background. CNC manufactured in stainless steel. Comes with correct imperial red fibre washer.
This version is CNC manufactured using an original 276 base plug as a pattern, and includes the distinctive curved head and imperial hex the original had (and as imperial hex is now difficult to obtain - this version has milled flats from round bar).
If you are not sure if your floatchamber is originally for a 276/289 roadgoing carb, or a TT type - the 276/289 floatchamber normally had 'AMAL' cast into the floatchamber body - and were of a grey pewter alloy material, while the TT floatchambers (that I have seen) did not have any words cast in the body and were normally of alloy material
This particular style of base plug was fitted to most roadgoing Amal Type 276 or 289 floatchambers - as used on most Norton OHV, SV and CS1 models from the 1930's through to the introduction of the Amal Monoblock in the mid 1950's. The screw also looks visibly identical to the base plug fitted to early Amal TT Floatchambers - however, the thread diameter on this plug screw is 1/4", while the example of the early TT floatchamber I have in my possesion is 7/32", i.e. it will measure approximately 0.206" in diameter. Amal's may have made an early TT floatchamber of this type with 1/4" thread, but I have not seen one. Therefore if you have an early TT floatchamber you should check the thread diameter first - we sell the 7/32" version (Item 0848) as well, but if you do have a floatchamber with approx 1/4" (as per accompanying phtograph with digital caliper), then this is the correct item.
Final point - although only a small component, these base plugs appear in a very visible position close to the timing side of most engines, and originals are nearly always corroded or chewed (they rarely need to be removed, and are normally locked up if you try to take them out). Therefore, I have found replacing the original corroded item with this very pretty version can make a bigger cosmetic difference than would have been expected. I dont have a bike of my own fitted with a 276 carb, but I have included a picture of a SOHC engine with an early TT carb fitted with the same base plug head that shows this