Parts such as the Gasket Kit A: Pkg,head Cover (nas), O Ring,69.8x2.0, O-ring,7.8x2.2, Gasket Kit A are included in the Cbx1000 Supersport 1981 (b) European Direct Sales Gasket Kit A parts fiche.
The O-ring,15x2.5 is the cheapest item from this partsfiche.
The Honda GASKET KIT A has ten products enlisted in the schematic.