Parts such as the Front Wheel: Gear, Drive, Nut(661), Nipple, Grease(6a1), Tube (5h5) are included in the Yl2 1967 1968 Usa Front Wheel parts fiche.
The Washer(6a1) is the lowest priced item on this Front Wheel schematic.
In this schematic the "Brg,r-b 6202z 35mm 48g Nt" is used most often.