The most reasonably priced component used on the Xr500r 1981 (b) E-4 Cam Chain Tensioner is the Washer Seal, 6mm.
This E-4 Cam Chain Tensioner diagram displays the required parts for the Xr500r 1981 (b) E-4 Cam Chain Tensioner.
The E-4 Cam Chain Tensioner is made up of components including this Chain,cam which is the most expensive.