[HawgRyder]

CDI uses about 400 volts to fire the coil.
The regular coil is about 12V of course.
So....the primary of the coil (number of turns in the input of the coil) is more than in the 12V version.
Think of it this way...if you put 12V into a 400V coil...you get a voltage of about 1050 Volts....obviously not enough to fire a spark plug.
So....depending on the voltage you are switching with the distributer you must use the correct coil.
OK?
Bob