On this parts fiche the Bolt,flange,8x16 is the most specified component.
Parts such as the F-31 Bumper: Nut, Blind, 6m/m, Washer,plain 6mm, Bumper, R. Side, Bolt-washer,8x16 are included in the Cb400p 1979 (z) Police General Export F-31 Bumper parts fiche.