As I've found through my rigorous search on the interweb, we don't actually have CDI ignition on our bikes. We simply have a transistorized Kettering system.
In other words, we have transistors/pulse triggers that replaced the points.
Describing CDI Ignition:
http://www.jetav8r.com/Vision/Ignition/CDI.htmlQuote:
With the Kettering Induction ignition design, the coils are powered all the time at 12 volts and are commanded to collapse to spark by the ignition module. Here, the ignition module disconnects the primary winding coil ground. The coil secondary winding collapses to spark at about 30,000 volts. In the CDI design, the coils are not powered. They receive a short high (250 volt) pulse from the ignition module and then amplify that (100:1) to a much larger voltage spike (about 40,000 volts) . Since the potential output of a CDI coil can be over 40,000 volts you have stickers all over your engine bay reminding you that: This can KILL you!!
Quote:
TPI’s spark units have easily recognizable failure modes. A common one is when an attempt is made to start the bike after it has sat awhile and the battery is low. During starting, battery voltage normally dips when the starter is used but with less to start with, the battery’s voltage drops too low for the spark unit to operate, and the engine will not start due to loss of spark. Meantime, the transistor is overheating, and will soon permanently fail. This is such a known failure mode that Honda later added time-out circuits to their TPI systems, as did also other manufacturers. Another possible route to failure is the unthinking substitution of ignition coils having too low a primary resistance. Such coils will burn out the spark units. You have no doubt heard of this. High performance ignition coils have higher potential voltage output because they have larger primary to secondary winding turn ratios. There are two ways to build a coil with a larger turn ratio - either leave the primary the same and increase the secondary turns, or leave the secondary the same and decrease the primary turns. The latter method was once very popular. However, it results in a coil having lower than stock primary resistance. While not big deal on a points bike, whose points will merely arc a bit more, the transistors in a TPI system will not endure the increased current flow through the coil for very long, and the spark units will fail. We’ll address this issue again in Part 3. One thing you do not have to worry about with spark units is failures due to loss of ground. Their metal boxes do not physically ground, but rather, the spark units get their grounds through the green wire feeding back into the wire harness. And here are a few tips. When the ignition system is acting up, but it is mostly when the engine is warm, don’t suspect the spark units. The pulsers are likely the problem. When the ignition performs badly whether hot or cold, then the spark units become more suspect.
So it's actually not the higher voltage of an overcharging alternator that generally melts the sparkers, it's the low voltage of a bad battery after sitting for a while that causes the damage.
stolen from
http://www.hondacb650.com/index.php
