On this parts fiche the Washer-plain-small,8m is the most specified component.
A sample from the products for the Rear Hub include: Sprocket-hub,48t,al, Sprocket-hub,49t, Nut,castle,22mm, Cap,axle.
This Rear Hub diagram displays the required parts for the Kx450-e9f Kx450f 2009 Usa Rear Hub.