Discussion in 'Norton Commando Motorcycles (Classic)' started by pierodn, Aug 12, 2018.
Please, what is the thread of the Amal ADAPTOR SLEEVE?.
Piero - can you be more specific?
I thought it might have been the thread for the screw on adapter to a air filter rubber as in the thread on the back of an Amal.
I couldn't find my imperial micrometer but got 45.5 OD which didn't make much sense converted to inch.
The only pitch gauge that seemed to match the thread said 24G 3/16 whatever that means.
3/16 BSW is 24 TPI as I expect you are using a Whitworth pitch gauge so 20G is likely to be marked 1/4, and 32G is 5/32 etc. however, Amal threads can be CEI/BSC so possibly 1.8" (45.72mm) x 24 as there are 24 TPI Cycle threads and some with decimal diameters (1.29, 1.45") although the largest diameter on a CEI/BSC chart that I have found so far is 1 5/8 x 24.
I can't even tell which part we are talking about!
Are we discussing the exterior threads on the intake side of the Amal 932, where a velocity stack might be fitted?
At approx 1.809" actual, allowing for normal thread crest clearance I'd use 1-13/16 X 24 if I was going to have a custom tap made for cutting velocity stacks. Probably 60 degree. Without access to an optical comparitor anymore it would be hard to tell the angle...
Both Andover and Amal refuse to disclose this information?
Doesn't seem like it wd be a very big secret...