A generator system for a portable, residential or small business generator includes an engine, an alternator, a continuously variable transmission pulley system and a governor. The engine includes a drive shaft and a throttle. The alternator includes a rotor disposed on a rotor shaft. The continuously variable transmission pulley system includes a drive pulley coupled to the drive shaft, a driven pulley coupled to the rotor shaft, and a belt configured to engage the drive pulley and the driven pulley. The governor adjusts the engine throttle to control the speed of the engine in response to a speed of the rotor shaft.