If the stator is working the first thing I would check is the voltage regulator. I've had a few of them go on me. It's an easy fix and as long as prices haven't gone crazy it's not that expensive either.
Everyone here has good answers. If the bulbs are all blown then it would be the voltage regulator. If the just aren't lighting up, then check for voltage off the stator. If there is voltage across the 2 yellow wires while the engine is running, then I'd look for a short in the electrical wiring somewhere. A short will draw all the current away from the bulbs.