22.22mm = 7/8", so I'd be surprised if 22.5mm converted to any remotely common imperial size (don't have calculator handy, and CNBF looking for it...).
Tony, have you looked at rod-ends from National or Aurora? It won't be 100% as original, but it should be relatively easy to find a generic, male-right-hand-thread rod-end with the correct ID, and then weld a nut to the brake say. Also has the advantage of using a generic part, rather than a Yamaha-specific thing.
Its what I plan to do on my 250G, 250K, 125G, 125L....