On this parts fiche the Bolt,knock,5mm is the most specified component.
The Cam Chain/tensioner assembly is constructed from several parts from which the Chain,cam is the most expensive.
Parts such as the Cam Chain/tensioner: Nut,hex.,8mm, Springa,tensioner, Arm,chain Tension, Cam Chain Guide are included in the Z50j Monkey 1982 (c) Finland Cam Chain/tensioner parts fiche.