Hi Ron,
I am just starting a 3SE restoration in Australia and have found your thread very useful. Unfortunately mine is missing inner and outer primaries so I have quite a challenge ahead. I don't think I will be able to obtain the original pressed metal cases of the 3SE but am trying to get something that will fit at this stage.
I have been told a 3T or TR5 outer will fit, does anyone know what inner might fit my bike?
Cheers, Tony