For this operation, it is necessary to have a calibration thickness of 0.008 mm, which is the standard clearance for these motorcycles. The valves must be completely closed to be adjusted: turn on the ignition, slowly press the kickstarter, watch the battery charge indicator: as soon as the needle moves, stop. Press the decompression lever and kick the starter until the needle returns exactly to the center: we are at top dead center (TDC): now the intake and exhaust valves are closed and can be adjusted. Remove the round cover on the left side of the engine, which is held by some bolts: underneath there are two control rods and their adjustment systems (an upper nut, a screw adjustment, and a lower locking nut). Take a control rod between your fingers and move it up and down: you should feel a slight play. It should rotate freely when turned, but should not have axial play. If it doesn't move at all, it is too tight; if it has too much play, it will rattle. The goal is to tighten the adjustment until the play disappears, then loosen it until it reaches 0.008mm. Loosen the lower locking nut, tighten the upper nut, and adjust the central nut with a 13mm wrench. Tighten clockwise, loosen counterclockwise. Adjust with the thickness: when removed, it should lightly scratch. Once both valves are adjusted, make sure the rods rotate freely and have no axial play. Reassemble the cover, screw in the bolts, start the motorcycle with the kickstarter: the engine should have a "clean" and smooth sound.