Alternator (Stator)

The alternator produces the electrical power that charges the battery and runs the ignition, injection, lights and accessories while the engine is running. It replaced the older DC dynamo because it gives more output, especially at low revs.

On most motorcycles the alternator is a permanent-magnet type: a fixed coil assembly called the stator sits inside a rotor with magnets on the crankshaft end. It makes alternating current, which a regulator/rectifier converts to direct current at roughly 13.5–14.5 V.

Symptoms of a charging fault are a battery that keeps going flat, dimming lights or a battery warning light. Check the voltage across the battery with the engine running and the stator and regulator connectors, which can burn or corrode.