I guys I am new to the forum and have made a few post today. there is some interesting reading and good advice from you all. many thanks for that. it helped me make some decisions and what to do. i have now gone for the cafe racer look with 77/78 cb 550 k3 purely because getting parts for her in the uk is crap.
the only place that helps is david silvers.
I have gone for mono shock conversion with cbr 600 f2 swing arm and shock on reading post on here it should be a direct fit. but it is not. the pivot bolt for that swinger is 15mm the original is 14mm. and is also to short by approx 25mm, but with some thought. cuttting gringing and welding I got it sorted and it now fits.
The shock had to be mounted with the same geometry as the cbr 600. otherwise it will not work. again taking loads of measurements got it right. I have also fitted rear sets