The most expensive part in this assembly is the Gasket Kit A (mca).
A sample from the products for the Gasket Kit A include: O-ring,40x2.5, Gasket Kit A, Gasket,cylinder (mca), Gasket,head Cover (nas).
twelve components are shown in this Cb450s 1986 (g) France / Yb Gasket Kit A exploded diagram.