The twenty-nine Tz125 1999 4jt6 Belgium 294jt-100e1a Crankcase component parts are all listed in this schematic.
On this parts fiche the Bolt(4my) is the most specified component.
The most reasonably priced component used on the Tz125 1999 4jt6 Belgium 294jt-100e1a Crankcase is the Bolt, Hexagon Socket Head(1uy).