Abstract: A magneto ignition system for applications which require long burn times (usually measured in milliseconds), high spark energy to ignite the air/fuel mixtures used in racing applications and light weight. Such applications can use air fuel rations as low as 2:1. The magneto assembly includes a one-piece shaft having a polygonal center section with sides defining a plurality of magnet receiving surfaces. Each surface is fixedly provided with a magnet, preferably a rare earth magnet, with adjacent ones of the magnets being arranged to have alternating outwardly facing poles. A magneto housing contains an array of stator windings that surround the plurality of magnets. The housing also includes opposed apertures with bearings for receiving opposed ends of the shaft. A non-conductive retainer housing surrounds the plurality of magnets and is affixed to the shaft to counteract centrifugal forces acting on the magnets, thus retaining the magnets on the shaft.