AMAC Carburettor Twin used
28.3 mm both sides - 1 1/8" ID at clip fitting
Internal measurement ID 1"
Slide ID 1 1/8"
clip fitting back and front
maybe Douglas competition
5?.J.S 3405 Number is on the Nut
Headrace Bearing Set BSA B44 top+bottom
OD of caps: 2 1/8" - 54 mm
Depth: (just under 1/2")12,3 mm
Bottom Cone ID: 1 1/16" - 27 mm
Top Cone including cover plate ID: 1" - 25,4 mm