Thanks crutschow for answering this. To be honest, I don't know much about ignition, and I guess I misunderstood what you were saying, BrownOut. All I know is what I have read, and I have not had much experience with CDI. I guess I should have stayed out of this one
I think your praticipation is fine and appreciated. If I suggested otherwise, I apologize. The advantage of using high voltage, as I understand, is that is allows faster charging of the ignition system, thus allowing higher engine RPM. The high voltage required for a spark comes from rapidly changing the current in the seconday coil, and in accordance with the equation VL=L*dIL/dT. So, the higher the change in current ( the dIL/dT ) the higher the output voltage. There are two ways to accomplish a rapid change in current. The more common, as mentioned, is to use a low voltage primary in a flyback configuration. A low voltage is applied to the primary and the primary current slowly builds up, creating an expanding magnetic field. Then, the current is suddenly interrupted, and the field collapses. The secondary voltage is given by V=Ns*dθ/dt, where θ is a product of the magnetic field created by the primary current. when the primary current is quickly interrupted, the dθ/dt term is very high, creating the high dIL/dt in the secondary. Note that it takes some time for the magnetic field to build up in this scheme.
Another way to get a rapidly changing magnetic field is to apply a high voltage to the primary. Thus, the equation IP=LP∫VP*dt, where IP is the primary current, LP is the primary inductance, and VP is the voltate applied to the primary, this current rises quickly, due to the high voltage being applied. This created a rapidly expanding magnetic field that induces the high voltage in the secondary given by the equation above. So, the high voltage is created upon the application of the primary voltage, rather than on the interruption of the primary current. The advantage is that the high voltag doesn't need as much time to charge as the primary current did in the first case, and so higher PRM's can be achieved. This is important in small 2-stroke engines, because for one thing, they develop their power at high RMP, and also because the ignition has to fire at twice the rate as a 4 stroke would.
You might use these principles in your high voltage experiments.
Hope that explanation also answers this question:
How can it give more top end power by decreasing the times it spark?
It doesn't. The CDI allows for higher RPM as described above.