So after lurking here for a while, and getting great help from stalwarts like RBM, it is now time to share a bit of what I have been doing, and what I have lined up for this winter - it is winter here down in New Zealand btw.
The original bike was a pretty tired looking K75S that had done 117,000kms. When I got it the petrol tank was leaking, the rear pads were down to metal, the fan motor was seized and it had some back yard repair that included a rear brake reservoir from a Holden Barina car, and ordinary rubber lines for the rear brakes, secured with hose clamps. This was just the start!
At this point I have just got to cutting the rear frame hoop off, obtaining parts and fabricating up seat mounts etc.
There is 30 years of accumulated grime and oxidised alloy to clean up, and that is taking a huge amount of time.
Tried Soda blasting, but my home compressor is maxxed out at 60 PSI, so I need about 50% more in order to get that idea to fly.
So far I have used a lot of CAD resources (Cardboard Aided Design) - and have templates made up for mudguards and various mounts, which will get sorted out in the next few weeks when I can scrounge some suitable bits of stainless plate.