Try MTX125R, CB250RS, XL250/500/600R......
I'm sure there is an Italian firm knocking news ones out on ebay. I'll have a mooch around and look-see.....
Try giving Paul a ring. XR Parts.He is in Wigan and a real nice guy.Probably have a new or used one.07961574799. You can tell him "Jim from Exeter gave you his number" if you feel the need.
I eventually had it rewired ( kept all the Honda wiring/plugs ) professionally.
Then went right through the bike, new plug; oil and filter; re-oiled air filter ( tis a Stage 1 professionally tuned bike ) valves adjusted; greased; cleaned up etc etc...lot of work.......then this happened ( and a smaller version on the other leg )...so bike perfect now...but sitting there useless for the foreseable future