The stator is the stationary part of the system. The rotor when in motion causes the stator to generate electricity. Sometimes simple things like rust building up on the face of the stator will keep it from producing electricity.
To be more specific. The stator contains multiple coils. The magnets of the flywheel spin past the stator coils, creating electricity. This electricity powers the power pack and battery charging system. When the triggers signal the powerpack, voltage is dumped into the coils to fire the spark plugs.
