1. First, turn the magneto counterclockwise, align the T-dash line of the magneto rotor with the inspection hole mark of the engine housing, and make the piston at the top dead center.
2. Secondly, the O point of the timing sprocket faces the front of the cylinder head. As the two cams of the camshaft tilt backward, the timing sprocket is installed on the camshaft, and the rocker arm of the magneto valve will not move.