On this parts fiche the Bolt,flange,6x25 is the most specified component.
The most reasonably priced component used on the Ns400r 1985 (f) South Africa Left Ctankcase Cover - Gearshift Cover is the Bolt,flange,6x12.
This Cover,shift is the most expensive of the items that make up this Left Ctankcase Cover - Gearshift Cover assembly.