Anyone done it?
I did in 1984 on my XS.
A number of years ago (1984), I was stripping the XS I have and having a load of bits powder coated.
I decided to try and uprate the front brakes as the non used side (left hand side) of the forks had the mounting bracket for a second caliper.
I sourced a second hand disc, caliper and also got a master cylinder from an XS11. New pads and a set of Goodridge brake hose and a few olives to make up the pipes, fitted and now I'm scared of the front brakes.
Worth considering if you want better braked front end.