I bot this off a fellow in Oregon and he said it fit a R65.. I loved the 77 100RS and just the year before I bought a new R90S... sold when I move to the island with 25 miles of road and no bridges to anywhere.
So I dropped off the biking world for 30 years.. went sailing and got into sailboat racing.
Anyway I picked up a tired R75/7 and decided to fix it up. One of the improvements was this fairing. It offers very good protection and is an eye catcher. There is a spider frame mount that connects to the head stock with a rod support under the tank. I was not able to fit the belly pan.. it is short by about and 1". Have to modify to fit. The headlight is the unmovable mounting point. So it now runs without the belly pod.
These fairings are rarely seen.