A bad voltage regulator can leave you stranded.
The voltage regulator on a Harley Davidson, when coupled with the stator, acts as an alternator for the motorcycle. If your voltage regulator fails, the battery will either receive too much of a charge and fail or it will not receive enough power and it will slowly drain, leaving the motorcycle without enough power to start or operate. Of course the first step in fixing a voltage regulator is locating it. Fortunately, most Harley Davidson parts are easily located due to the open design of the motorcycle.
1. Park your motorcycle in a stable and level space. Ensure the kickstand is down and the motorcycle is stable.
2. Aallow the motorcycle to sit for a while so the engine components can cool off, if needed.
3. Look between the motorcycle’s front wheel and engine, near the bottom of the engine block and between the frame rails. This is where the voltage regulator is located. The regulator is usually black (but is sometimes chromed), oval- or rectangular-shaped and about 5 inches by 3 inches (this can be 5 inches wide by 3 inches high or 5 inches high by 3 inches wide depending on the year and model) with a wiring harness coming out of it bottom. It is secured to the motorcycle by two bolts.