The Tappet Cover is made up of components including this Valve Lifter Comp which is the most expensive.
eight components are shown in this Xr650r 2003 (3) European Direct Sales Tappet Cover exploded diagram.
A sample from the products for the Tappet Cover include: Oil,seal,11x16x5, Cover,tappet Adj, O-ring,66mm, Bolt Flange Nshf 6x2.