The most reasonably priced component used on the Atc110 1982 (c) Usa Handlebar / Top Bridge is the Washer,plain, 6mm.
In this schematic the "Bolt Hex 6x28" is used most often.
Some items from this specific schematic: Bolt,hex.,12x25, Nut,steering,stem, Holder A,upper, Washer,plain, 6mm.