The downsides of AC ignition

What is AC Ignition and why DON'T I want it?

Despite the supposed benefits mentioned previously, an AC ignition system is a poor choice in most powersports applications.  

Highly sensitive component used in stator

The problem lies in the necessary components of the AC ignition system, the source coil on the stator that produces ignition power, and the AC powered CDI box, responsible for sending power to the ignition coil for spark production at the right time.  An AC ignition system means that the vehicles ignition is powered by Alternating Current (AC) produced by the isolated source coil on the stator. The source coil is made of many turns of extremely fine wire (think almost human hair thin) that is very sensitive to heat and prone to failure due to it's small diameter.  This small wire diameter is necessary to produce the very high voltages necessary to power the CDI box.  

Variable performance at different RPMs

The nature of producing Alternating Current ignition power directly from the stator means that it is variable based on the RPM of the engine. Significantly higher output is generated at high engine speed than low engine speed, which often effects low RPM performance.  The CDI box must also be able to withstand the peak inputs at high RPM consistently, and often fail from this continuing stress.  These common failures and more put an AC ignition system at clear disadvantage.