Parts such as the Rear Swinging Arm: Shaft,rear Swing Arm, Nut 16mm, Bush, Pin 20x20 are included in the Gs1000ec 1978 (c) Usa (e03) Rear Swinging Arm parts fiche.
Of all the components that make up this Rear Swinging Arm the Pin 20x20 has the lowest price.
With two applications this Bearing(25x33x30) is the most specified part.