The eight Gp125 1979 (n) (e01 E02 E04 E06 E13 E17 E18 E21 E22 E24 30 35 41 Muffler component parts are all listed in this schematic.
In this schematic the "Lock Washer" is used most often.
Some items from this specific schematic: Bolt(5x8), Pipe, Baffle, Muffler Assy, Lock Washer.