[Rubone]

No Mystery, that is a Sportster hub with a British brake bolted to it. No H-D spacer will work. If you are going to run it you will need to fab all the parts to do so!
Robbie

 

[Rubone]

You also need to be aware of some other issues. The sprocket is much smaller than a BT type so you will have to adjust gearing to work , and the brake is much smaller than a BT type so you need to take that into consideration as well! And once you get the chainline right you may need to offset the wheel lacing to get it to be centered in the frame as the braks drum is narrower than BT and will set the whole wheel off to the left!
Robbie