Puch CDI

Revision as of 11:27, 19 April 2012 by Sickster (talk | contribs)


The CDI kit shown here can be used on ZA50 and E50 Puch motors. Most of the time they can be bolted in directly without modification. However when switching the CDI unit between the E50 and ZA50 the ignition coil must be unscrewed and flipped over then re-installed. This is due to the rotational direction of the engines being opposite, thus the electrons in the coil will be moved in the wrong direction by the magnetic field of the stator, failure to do this will result in a weak spark at the spark plug.


For the E50 it is installed as shown below. You will have to remove the brown ground wire from the back and put it on the front. At the same time you should swap the screws on that coil, as the longer bolt interferes with the case if left on the left side.

Some kits required enlarging the adjustment slots in the plate in order to get full advance. Others have bolted with no issue. If you find that your timing is retarded still with the plate at full advance, you likely need to break out the dremel. Moving the pickup to the other side causes it to be advanced too far.


The 12v CDI Ducati exciter coil on the stator plate (white wrapped) from a Puch Korado, will also work on this CDI kit.

The white wrapped with red lead coil is the (high tension coil) or the high voltage coil for the spark. The other coil with the yellow lead is the light coil or low voltage, it puts out a range of around 12volts up to and over 20 volts @ high revs. That's why you should run a voltage regulator so you don't blow your 12volt bulbs.


For the ZA50 the plate is installed as below. It should bolt right on, no reported need for modifications.


Failure and Repair

These cheap CDI's are notoriously unreliable, and of those I've surveyed about 50% fail within the first month and 80% fail within the first year. The cause of failure is believed to be due to the inability to dissipate power if it fails to ground through the plug. This can be caused by a loose plug boot, pulling the plug boot off to kill the bike, a bad ground for the CDI, or sometimes just by ordinary use. One thing is almost always true, when it fails it is the CDI Box/coil unit, and not the stator coils. The pickup coil (small white) has also been known to fail.

The wiring is as follows:

From the stator:

  • Red - Ignition Power
  • White - Timing pulse
  • Yellow - Lighting
  • Brown - Ground

On Box:

  • Red - Ignition Power
  • White - Timing pulse
  • Yellow - Lighting
  • Black- Kill (ground to kill)
  • Black/white - Ground


If your CDI stops working, and you've tested for spark using a new plug and a new boot: 1st - check for power out of the CDI box, try at the plug wire If you have power here but no spark, you need a new plug or boot. If not proceed to #2

2nd - remove the wires and measure voltages from the stator - Red should put out over 5V, white should put out small (<1V) but measurable pulses. You can use a drill with a 15/17mm socket to spin the crank to test voltages easily. If you have power from the stator red and some power on the white, your coil is bad, Proceed to replacing the CDI If you have no power on the red, your power coil is bad and you will need to replace the stator (or just the coil) If you have power on red but nothing at all on white, your pickup coil is bad. this can be rewound or replaced. Also try moving it on the stator to where it sits nearest to the magneto and try again to see if you can get power out of it.

Replacing the box/coil

Using the wiring above you can wire in a new coil and box.