GN250 or GN125 fork and other compatibility queries

[chasio]

I picked up a cheap GN for Mrs Chasio to learn on, which is a cool wee bike in good nick.

It's got a drum front wheel, so I was thinking of trying to pick up a disc front end (from lever to wheel) and slotting that in. Spoked would be perfect or I'll need a rear wheel to match. I'm considering getting a whole spares bike with spare indicators, levers, mirrors, etc....

I looked at a donor candidate yesterday and it is in pretty sorry state fron being stored outside and general neglect. It has many issues, but specifically it has lots of rust on the uppers, including below the clamps. So, I am wondering if it is possible to use the uppers from a drum Ginnie front end ('84) on the lowers of a disc one (later Japanese era). (Incidentally, the caliper was a bit sticky but pads were good and disk looked OK. The reservoir glass looked to have marginal life but not visibly leaking yet).

Alternatively, would a Chinese made 250 or 125 front end bolt up onto an '84? Or maybe I could find another model of bike altogether for the front..? Ideas welcome.

From my searches here and elsewhere on Japan vs China compatibility, the only issues were the rear grabrail / rack mount and the general iffy manufacture of the later ones. Anyone know of other issues?

Thanks in advance.

[chasio]

Adding some pics of potential donor bike FYI... And do the headers looks like they have much life in them to you?