On this parts fiche the O-ring 13x3.0 is the most specified component.
Of all the components that make up this Gasket Kit B the Washer,plug,drain 12 has the lowest price.
Parts such as the Gasket Kit B: O-ring,14.8x2.2, Gasket,starter Co (mca), O Ring,21.5m/m, Washer,sealing,6. are included in the Cbr500f 1987 (h) Austria Gasket Kit B parts fiche.