TT, What caps are you referring to? I do not have any info on coils however.
If indeed the Gerex is a CDI system (Capacitive Discharge Ignition), it has to have capacitors. These are usually electrolytic and they degrade/become resistive with time. They become resistant to being charged and then quickly bleed off their charge, leading to poor spark voltage.
CDI's change 12V from the battery and with an oscillator, a capacitor, and a transformer, turn that 12V into 300 or more volts. Feeding 300V pules into the primary of the spark coils produces far more voltage at the coil's output than the standard 12V input on the primary of standard coils. The coils make a spark voltage relative to a turns/ratio. If 12V made 12000 V spark before. That would be a 1 to 1000 ratio. In theory, the same coil would then produce 300,000 V when fed 300V on its primary. The actual gain is not that large, due to various physical factors of coil design. But, getting spark voltages of 30,000-40,000 from coils that previously made only 12,000 was not uncommon. CDI coil output voltages approach those of todays modern High energy ignition systems.
CDI's normally provide several 300V pulses to the coil primary during each spark event (multifire). This allows big gaps at the spark plug even when the compression in raised. Very good for power and MPG, as well a spark plug longevity.
The downside to CDI's is the quality of the electrolytic capacitors. In the 70's, Electrolytic caps of good quality were very expensive. Cheaper ones worked, but they did not stay good over long time periods. It was usually worse when the caps sat without a charge on them, disused.
Cheers,
