AC-CDI v2.6

v2.6

Characteristics.

  • For ONE or TWO* cylinders
  • Highly adaptable.
  • Can handle different pickups coils (Yamaha,Honda,Suzuki,Kawasaki,Zongshen)
  • Use the first pulse of the pickup signal for HIGH RPM, maximum power.
  • Use the second pulse of the pickup signal for LOW RPM , idle and easy start.
  • Works with 1 or 2 pickups.
  • RPM when CDI jump from LOW to HIGH is adjustable.
  • 2 LED indicators.
  • YPVS output to drive an YPVS box.
  • Need a working charging coil for the capacitor. (or a DC converter)
  • Doesn’t need a battery
  • No rev-limiter (Tested at 20,000rpm)
  • Running unit available in the SHOP.

Limitations.

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

  • If any, connect Neutral switch wire to Neutral indicator.
  • If you need “Side-stand security” then connect the Sidestand switch to the KILL input on this CDI.
  • Only works with VR pickup (Variable Reluctance AKA pickup coils)
  • Cannot work with Hall sensors or points.

WIRING

  • How To wire this CDI?
  • How To hook this CDI on a Yamaha XT600

  •  

    How does it works?

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

    When the pickup is triggered, the CDI turns on 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.

    Here is a interesting video description of how a CDI works.


     

    Switches positions

    See Switches functions.

    sw 1: ON= 1 pickup connected to HI input
    .... OFF= 2 pickups connected to HI and LO inputs
    sw 2+5: ON= The first pulse of the pickup used for LOW rpm is Positive (PN)
    .... and the second pulse used for HIGH rpm is Negative
    sw 3+4: ON= The first pulse of the pickup used for LOW rpm is Negative (NP)
    .... and the second pulse used for HIGH rpm is Positive
    sw 4+5: ON= The first pulse of the pickup used for LOW rpm is Positive (PP)
    .... and the second pulse used for HIGH rpm is Positive
    sw 6: ON= Half Wave rectification: Normal spark. One side of the stator is connected to Ground.
    .... OFF= Full Wave rectification: Strongest spark. Stator is disconnected from Ground


    Sensitivity
    This CDI needs a pickup that puts out 3 to 30volts.
    For pickup that puts out more then 30volts, cut the JP1 jumper to increase the range of RV2 trimmer.

    It 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.


    LED
    LEDs have “N” and “P” labels. They turn on when the CDI receive a Negative or Positive pulse on HI input.


    YPVS
    An YPVS output is available to drive a Yamaha Power Valve System control unit. (Y/G wire)
    (Cannot drive the step motors directly.)



    Compatibility

    Compatible bikes


    Partially compatible bikes


    Not compatible bikes



    TROUBLESHOOTING

    Click here for more info
     

    Step 1

    See: troubleshoot step1
    – Don’t connect any pickup
    – Don’t connect the Kill Switch
    – Connect the ignition coil to the COIL output of the CDI.
    – Remove the sparkplug from the engine and connect it to a GOOD metal frame (ground)
    – Connect the charging coil to the 2 ALT inputs of the CDI.
    – Connect a DC voltmeter between Ground and KILL pad.
    – DIP Switch N°6 can be ON for full rectification or OFF for half rectification.
    Other DIP switches positions don’t matter for step 1.
    Then:
    – Kick start or electric start a few times to load the capacitor.
    The voltmeter should raise up to 100 or 200Vdc.
    If not: Check grounds, connections, joints, charging coil (stator), change switch 6 position.

    Step 2

    See: troubleshoot step2
    – Don’t connect any pickup
    – Don’t connect the Kill Switch
    – Turn DIP Switches positions 1, 3, 5 to ON.
    – Turn RV1 and RV2 to the minimum resistance (Position: 0)
    – Kick start or electric start a few times to load the capacitor.
    – Once the main capacitor C1 is charged and the voltmeter shows 100 to 200Vdc, then:
    – Connect a 12v battery between GND plug (ground) and HI input:
    Led turns on.
    – Capacitor discharge into the ignition coil and one spark must fire at the sparkplug.
    If not: Check grounds, connections, joints, SCR, ignition coil, spark plug cables, spark plug.

    Redo this Step 2 but this time connect the +12v plug from a battery to the LO input.

    Step 3

    See: troubleshoot step3
    – Don’t connect the Kill Switch
    – Kick start or electric start a few times to preload the capacitor.
    – Once the main capacitor C1 is charged and the voltmeter shows 100 to 200Vdc, then:
    – Connect the pickup coil between GOOD metal frame (ground) and HI input of the CDI.
    – Kick start or electric start.
    When the piston approaches the TDC and pass in front of the pickup, a positive pulse is send by the pickup and trigger the SCR.
    LED blinks and the capacitor C1 discharges into the ignition coil and a spark must fire at the sparkplug.
    If not: Check grounds, connections, joints, pickup coil, RV1 and RV2 are at 0, reverse the 2 wires of the pickup coil.


    VIDEOS.

    Click here for more
     

    • Version 1.0:
    • Version 2.1:
    • Version 2.2:

    • Marty bought a 1984 wrecked XT600 without ignition and harness wiring.
      Got it running again even if it seems like he has some carbs works to do…
    • Analog CDI v2.2 fitted a Scooter:
    • Analog CDI v2.4 on a DR125:
    • Analog CDI v2.4 on a XT125/1982:
    • Analog CDI v2.4 on a XT400:
    • Analog CDI v2.4 on a XT600:
    • Analog CDI v2.4 at 10,000rpm:

    • Analog CDI v2.4 at 15,000rpm:

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