More of a Burman question than an Ariel one, but here goes:
I have couple of 20s lightweights with two-speed Burman gearboxes - a type A and a type J, if the serial numbers are reliable.
Each has the same kickstart arrangement as the boxes on the 1920s black Ariels, from what I can see on Google. The 1924 box has a 91mm diameter tin kickstart cover, which seems to be a common size for other 20s Burman boxes.
I want to see if the stop-peg rubber will fit into these boxes - I've had to have the case welded on the 1924 box, as it had cracked around the stop-peg - which seems to be a complaint on the 20s Ariels.
Can anyone give any dimensions of the rubber that fits on the peg (bore, outside diameter, width)?