<P> Capacitor discharge ignition (CDI) or thyristor ignition is a type of automotive electronic ignition system which is widely used in outboard motors, motorcycles, lawn mowers, chainsaws, small engines, turbine - powered aircraft, and some cars . It was originally developed to overcome the long charging times associated with high inductance coils used in inductive discharge ignition (IDI) systems, making the ignition system more suitable for high engine speeds (for small engines, racing engines and rotary engines). The capacitive - discharge ignition uses capacitor discharge current to the coil to fire the spark plugs . </P> <P> The history of the capacitor discharge ignition system can be traced back to the 1890s when it is believed that Nikola Tesla was the first to propose such an ignition system . In U.S. patent #609250 first filed February 17, 1897, Tesla writes' Any suitable moving portion of the apparatus is caused to mechanically control the charging of a condenser and its discharge through a circuit in inductive relation to a secondary circuit leading to the terminals between which the discharge is to occur, so that at the desired intervals the condenser may be discharged through its circuit and induce in the other circuit a current of high potential which produces the desired discharge .' The patent also describes very generally with a drawing, a mechanical means to accomplish its purpose . </P>

What does cdi stand for on a motorcycle