In most motorcycles use one of three types of ignition
In a battery type ignition (Kettering) an ignition coil (spark coil) is supplied battery voltage through a set of points. The opening and closing of those points creates an expanding and collapsing field in the ignition (spark) coil which crates a spark to the plug. Spark voltage in this style system is usually 15-20K volts.
The system depends on a fully charged battery which is depleted over time with the heavy current requirements of the system. The battery is recharged through the alternator charging system.
This system must have a fully charged battery and charging system to operate.
Sparkplugs are normally gapped much smaller than with CDI systems because of the lower spark voltage produced.
The S series Triples and the H1B use this type ignition system.
Electronic ignition systems utilize an electronic "box" that must be supplied battery voltage to function. This box is used to convert low voltage from the battery to ~350vdc which is used to charge a capacitor, then applied to the spark coil when triggered.
The "signal coil" is located in the alternator housing and is sometimes referred to as a stator coil which is technically not correct. The stator coils (windings) are a part of the charging system.
The "signal coil" voltage is amplified in the "box" to trigger the CDI.
This high voltage from the "box" is supplied to the spark coil through a distributor system. The ignition coil (spark coil) will produce ~30kv.
A battery is required in this system to provide power for the "box" circuitry and, therefore, a charging system is required to maintain battery voltage.
The advantage to this system over the Battery Ignition system is a higher spark voltage and no point wear/adjustment. However, it requires a signal coil and an electronic "box".
This system is used in the early H1 models (H1/A/C).
The magneto CDI system is self contained and requires no battery to function. It is comprised of a CDI unit "box", ignition coils, ignitor coil(s), and a trigger system.
The "ignitor coil(s)" is located in the alternator housing and is sometimes referred to as a stator coil which is technically not correct. The stator coils (windings) are a part of the charging system. Another term for ignitor coil is "hi/low speed winding" or "ignition winding".
The voltage from the ignitor coil is fed to the CDI unit, rectified to ~325vdc, and applied to a capacitor.
The trigger system then discharges the capacitor and the voltage is felt at the primary of the ignition (spark) coil to produce ~30kv spark. The trigger system can be either points or a magnetic pickup system.
The advantage of this system is that it requires no battery or charging system, no point wear/adjustment, and high spark output with a relatively simple CDI "box".
This system is used in late model H1 (H1,D,E,F,KH500), H2, and KH400.
Note: Ignition coils differ between systems and should not be interchanged.