The Washer, Plain (646) is the cheapest item from this partsfiche.
Parts such as the Crank - Piston: Brg,r-b 6208 80mm 345g (6e5), Clip, Piston Pin, Crank Shaft 1, Piston Ring Set (2nd O/s) are included in the 150 175 200 Etj 1986 Crank - Piston parts fiche.
In this schematic the "Pin, Dowel(663)" is used most often.