Could it be your black box? Sure, particularly if your motorcycle is older, but still new enough to have CDI. YouвЂ™ve tested everything but the CDI unit, including the charge of your battery, your spark plugs, the health of your coils, and the triggering mechanism itself. The problem may get worse as the bike warms up. Symptoms could include misfiring, dead cylinders, backfiring, bizarre tach behavior, and countless other things related to how your engine's running. So youвЂ™ve got a spark problem on your CDI-equipped motorcycle.

But that doesn't mean they stay problem-free. Increased power, better efficiency, less maintenance, and fewer moving parts earned CDI, and systems like it, a good reputation. The ignition advance, once mechanically limited to a curve, could be tuned to squiggle any way you liked all the way to redline (read Lemmy's timing article if you'd like more on this). Electronics gave manufacturers new control over their engines.

That's all great, but the jump to CDI was like going from carburetors to fuel injection. In a points system, the crank basically opens and closes a switch. Motorcyclists accepted occasional maintenance in exchange for rugged reliability, easy adjustment, and cheap cost of replacement. These ignitions did just fine for decades, but those moving parts wear out over time. Springs, weights, cam lobes, and other simple machines worked together to deliver spark at the right time, even as revs rose. Andy Greaser photo.Д¬DI's complexity is in its circuitry, but its ancestors relied on clever mechanical systems to fire the coils. On an electrical engineering level, it's different from CDI, but the troubleshooting process is the same. For the purposes of this article, I'll refer to all the black box ignitions as CDI, since they all use the same basic components: box, coils, sensor. In addition to discharginвЂ™ those capacitors, the box may also influence your rev limit, timing advance, and other variables related to spark, but thatвЂ™s it.ДЄ popular variation of this system is TCI, which doesn't use capacitors in the same way. The trigger tells the box to fire, the box determines when to fire which coil with the capacitors, and zap goes the spark plug, ad infinitum. The basic CDI system is a trigger mechanism, coils, and a box, often black, with capacitors and other circuitry inside. You'll often find them lurking under your seat. What sets them apart is their ability to release all that energy near instantaneously, which is ideal for an ignition circuit. Let's take a look inside.Д¬DI stands for capacitor discharge ignition (alternatively, вЂњcapacitive.вЂќ) If youвЂ™re new to capacitors, theyвЂ™re similar to batteries in that they can store energy for later. If you're not, you're wondering what a CDI does. If you're lucky, you're reading this for your own education. Black box, brain box, pulse pack, igniter box, CDI module, power pack, whatever you want to call it: if your motorcycle is newer than 1980, it probably has a black rectangle spouting wires under the seat that makes the magic happen.

Cycle sounds magic box