The component with the lowest price in the CAM CHAIN / TENSIONER schematic is the Washer,plain, 6mm.
In this schematic the "Damper,tensioner" is used most often.
Parts such as the Cam Chain / Tensioner: Nut,hex.,8mm, O-ring,6x1.7, Bolt,flang,6x16, Tensioner,cam are included in the Cb400f Super Sport 400 Four 1975 Cb400fk0 Usa Cam Chain / Tensioner parts fiche.