Check out any of the eight Trailer Hitch / Luggage Carrier components enlisted.
Parts such as the Trailer Hitch / Luggage Carrier: Bolt,hex.,8x16, Bolt,hex 8x16, Carrier, Luggage, Bolt,hex,8x20 are included in the Fl250 Odyssey 1980 (a) Usa Trailer Hitch / Luggage Carrier parts fiche.
In this schematic the "Spg-washer 8mm" is used most often.