Stainless Steel pan washers of the same size as those used on the Upright gearbox pointer bolt (see also Item 0273B for the pointer itself) or rear of Norton chaincases where they attach to the rear engine plate mount stud (help stop chaincase from splitting). Stainless Steel.
These wide washers help stop deforming the chaincase and one was originally fitted (see Item 10 on the attached exploded diagram taken from the 1948 catalog).
Price is for a pair