FYI for anyone interested. I have done some searching around this, and like anything it can be done a few ways but would require a solution to the 4 inch rear wheel scrubbing the swing arm and keeping the wheels in line. So either a custom swing arm or fabricating the existing mono shock to the XS frame, and as a chap told me if you go to that much bother you may as well go for a custom frame rather than a 30 yr old jap frame that is prone to rusting from the inside-out, it was worth looking into but that idea is firmly out of my mind now