Speedway Bike Explained:

IGNITION

The ignition systems on speedway bikes have varied over the years, but still maintain the basic fundamentals of a magneto based spark.

Some have a seperate rechargeable battery system supplied by Interspan. As well as providing a more powerful spark than traditional systems, there is a theory that the power required to turn a magneto (the Jawa's ignition system) is wasted energy. Therefore, the seperate battery box supplied both low and high tension power, with a simple trigger on the motor (contact breaker points) used to time the spark.

Many top riders of today still opt for the Interspan system, believing this theory holds true, although nowdays the points have been replaced with Hall effect solid state electronic triggers.