The Dyna ”S” is a high performance ignition system that installs into any Big Twin 1970-1999 or Sportster 1971-2003 cam cover. It features a magnetic rotor (sender) in combination with base plate mounted receiver. Models equipped with factory electronic ignition systems require a complete advance unit assembly.
Available as dual fire - both cylinders fire at the same time (like stock) - or single fire, i.e. each cylinder fires individually at the end of its compression stroke.