I had given to me a few years ago a Honda CB250G5 that was not worth renovating,so I sold off the parts. What I did find was that there was a big similarity between the front end of the G5 etc and the front end of the CB400 Four.This made things a lot easier to sell on.Even the seat fitted the 400F,but to purists this would be unthinkable.
As far as I remember even the back end fitted the 400F.