AC-CDI analog v2.4



  • For ONE or TWO* cylinders
  • Highly adaptable.
  • Can handle different pickups coils (Yamaha,Honda,Suzuki,Kawasaki,Zongshen)
  • Use the second pulse of the pickup for LOW RPM , idle and easy start.
  • Use the first pulse of the pickup for HIGH RPM, maximum power.
  • RPM when CDI jump from LOW to HIGH is adjustable.
  • LED indicator.
  • Need a working charging coil for the capacitor.
  • Doesn’t need a battery
  • No rev-limiter
  • Ready to use unit available in the SHOP.
  • Printed Circuit Board available in the SHOP.


This CDI only does the ignition task, it doesn’t use any safety like neutral and sidestand.

  • Connect directly Neutral switch wire to Neutral indicator.
  • If you need “Side-stand security” then connect Sidestand switch to KILL wire of this CDI


AC-CDI Analog v2.4
To build the CDI Parts list components.jpg
To wire the CDI Wiring HowTo hock this CDI on Yamaha XT600


How does it works?

This AC-CDI use the 100 to 200 Vac provided by the charging coil to charge a capacitor through a rectifier bridge.

When the spark time comes, the CDI trigger a thyristor that discharge the capacitor inside the primary coil.
This burst of energy into the primary induce a high voltage of few thousand volts into the secondary coil, enough voltage to create a spark at the sparkplug contacts.

The CDI is triggered by the pickup coil. There are different kinds of pickups:

  • Some bikes have 2 pickups, one for idle/low-rpm setting at 12° Before the TDC and another for high-rpm setting at 36° Before the TDC. ie Yamaha XT550-XT600
    – Connect the LOW pickup to “LO” input
    – Connect the HIGH pickup to “HI” input
    – DIP switch N°4, 5 are set to ON (1 is OFF)

  • Most bikes have only 1 pickup.
    – Connect the pickup to “HI” input
    – DIP switch N°1 is set to ON

    • This pickup puts out a sine signal that could be Positive then Negative (I call it PN) ie Yamaha, Honda
      – DIP switches N°3 and 4 are set to ON

    • or the opposite: Negative then Positive (which I call NP) ie Suzuki, Kawasaki, Zongshen, KTM.
      – DIP switches N°2 and 5 are set to ON


    This CDI doesn’t have seamless advance, it jump from LOW advance to HIGH advance.
    The moment when the CDI jump from Low to Full advance is adjustable by potentiometer RV2 (HI).

    Start tuning with RV2 at the maximum value (totally screw) then slowly unscrew it to lower the resistance, therefore the RPM where it switch.


    Compatible bikes

    Partially compatible bikes

    Not compatible bikes


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