On pistons with a notch on the head, which direction should the notch face?

In engines with a piston designed with a notch on the head, the notch should face towards the magneto. This orientation is crucial because the notch is intended to align with certain components of the engine, particularly for proper combustion and timing with the ignition system. When the piston is positioned with the notch facing the magneto, it allows for optimal clearance and helps maintain the correct sequence of ignition and combustion events, thereby enhancing engine efficiency and performance.

Aligning the notch towards the magneto ensures that the flame speed and direction of the combustion gases are properly directed, contributing to effective engine operation. Furthermore, this arrangement is often designed to avoid potential interference with components within the cylinder, ensuring a smooth operation and facilitating maintenance tasks. This specific orientation is standard practice in engine assembly and is critical for ensuring the engine runs smoothly and reliably.