Ignition retard

Retarding the ignition means moving the spark later in the cycle, so it fires fewer degrees before top dead centre (TDC). The opposite, advance, fires the spark earlier. Because the fuel needs time to burn, the ideal timing changes with engine speed and load.

Modern engine control units adjust timing continuously. They retard it to prevent knocking (pinking), when the engine is hot, to make starting easier, and as part of traction control or quickshifter cuts. On older bikes timing is set mechanically with points, a centrifugal advance unit or by rotating the pickup.

Too much retard makes an engine sluggish and hot-running, while too much advance can cause knocking and piston damage. Set timing to the manual's value with a strobe lamp where applicable.