I noticed on fleebay a few sets of cbr600rr fork stanchions with the radial mounts on the bottom......so will they fit into rvf400 forks ? They're both 41mm , would be a cheap way to go radial if you already had rvf forks ( or an rvf)

Probably but as with all caliper adaptors they look gash.

If you have RVF forks replace them with 675 forks and brakes as they go straight into the RVF yokes.

Not an adapter, the actual whole stanchion and fork bottom from a cbr600rr 2007-2012 .

The only one ive seen with the 2007-2012 cbr600rr forks was a complete front end replacement on a nc29, so yokes, forks, cbr 6 wheel and brakes too