Nice one mate, thanks for the info. I’ll try tracking down a C bracket.
I thought the Lester would go straight on, but then I would have wire rear wheel and mag front.
Now I put a bit more thought into it I could just add a disc to my wire wheel as the tire is new and the wheel is only 4 or 5 years old.
The Lester and the wire are interchangeable, so the amount of work to install the dual disk is exactly the same regardless of which wheel you use.
The CB500K, 550K and F, 750K1-6 and F0/1, early 750A, and 75-77 GL1000 all use the same front hub (the 750A and GL use an aluminum rim) so all of these bikes use the same Lester front wheel. When I sold my 550F I kept the Lesters that were on it and installed wires. My 750F has the front Lester on it now. Since I used an F2/3 front end I had to shim the rear mounted calipers to work and use 550 rotors, but if I had installed it on the stock F1 front end it would have bolted right up using the stock F1 rotor.