GZP Advance unit H-D shaft/plate/springs
The Dyna S is a completely self contained electronic system that fits behind the ignition cover. It uses a magnetic rotor and "Hall Effect" magnetic sensors which are not affected by RPM changes, dirt and/or oil. The Dyna "S" works with a stock or aftermarket mechanical advance unit. It is designed for street, touring or strip and faster setting than points. There are two versions available, the Dual Fire High Performance system which simply replaces the conventional points ignition, and a Single Fire version. Single Fire does not fire both cylinders at the same time, but only the cylinder that is at the end of its compression stroke. This means that the piston which is in the overlap position will not be fired needlessly. Both systems are easy to install without any modification and have a 3 year factory warranty. Both Dual Fire and Single Fire systems fit Sportster 1971-1979 and Big Twin 1970-1979. Kits can also be installed on 1980-1999 single cam Big Twin and 1980-2003 Sportster when a mechanical advance unit is used.
Note: Dyna S ignitions are to be used with 5 ohms coil for street use. Coils with 3 ohms primary resistance are suggested for race use only.