View Single Post
Old 10-21-2008, 11:18 AM
brucemg51 brucemg51 is offline
Motorized Bicycle Elite Member
Join Date: Jul 2008
Posts: 157
Default 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?
Reply With Quote