What's the black box for?

brucemg51

New Member
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 MB 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?
 
i think this is correct dont quote me but a magnetos spark is regulated by the fly wheel so its only option in incresing spark regulation is by increasing speed of motor by of course adding more fuel - hopefully u understand what i mean -

where as a cdi regulates voltage/ and speed of spark thus working in conjuction with fuel increase to deliver an all over performance improvement--

p.s. "WARNING' it is very very late were i am so i could be just raving

IF I'M WRONG PLEASE SOMEONE CORRECT ME SO I GET IT RITE

peace!!!
 
Yes, you are raving....

The mower does have a cdi or points/condenser set up. It's just not open to the eye like a bike engine.

The cdi on these bikes doesn't change spark timing, intensity, duration or anything else.
 
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