What's the black box for?
It occurred to me while mowing the lawn that the motorbike has an extra part that my lawnmower doesn't. On the single cylinder Briggs & Stratton mower engine, the spark plug wire goes directly from the magneto to the spark plug. Whenever the mag makes a revolution, it induces a spark to the plug. Why do these motorized bicycle kits have a CDI ignition unit? Is it really necessary for a single cylinder engine? Is it because the lawnmower engine is four stroke rather than two?