The Ring B.stopper is the lowest priced item on this F-28 Rear Cushion schematic.
The Gl1200i Goldwing Interstate 1986 (g) F-28 Rear Cushion consists of twenty-one pieces with the Cushion Assy Rr being the most expensive.
With five applications this O-ring,5.8x1.9 is the most specified part.