AC-CDI v12

Ignition system – Programmable AC-CDI

AC-CDI v12 is End Of Live and has been replaced by AC-CDI v14

This technology will make your motorcycle tuning much simpler and faster.
Just connect your phone to your motorcycle and you’re ready to go!

A programmable ignition is extremely valuable in repair work as it fits a wide range of bikes.
It’s especially useful if the original part has been discontinued or is overpriced.
And of course it’s a must-have if you are wishing to tune the engine.


  • Programmable AC-CDI
  • Suitable for ONE or TWO* cylinders
  • For [2 strokes engines] and for [4 strokes engines with wasted spark*]
  • * On 4stk engines with a pickup on the crankshaft, one spark occurs during the compression stroke and another during the exhaust stroke.

  • Easy programming via WiFi connection.
  • You need a simple web browser on any smartphone or laptop. (No app)
  • ONE or TWO programmable ignition timing curves. *
  • Rev from 10 up to 30,000 RPM.
  • 0 deg advance from 1 to 500 RPM. (To avoid kickback)
  • Adjustable timing in 13 steps from 500 to 20,000RPM.
  • Rev limiter.
  • Live Display of RPM and Timing via Wifi.
  • 1 input for an inductive pickup (VR). Pickup polarity MUST be Positive first.
  • 1 input for an Hall Effect Sensor, Optical sensors or Points (An external resistor is required) *
  • VR conditioner to extract pickup signal in noisy environment.
  • 1 output for a Capacitive coil type.
  • Stator can be half or full rectified. (For more power and ground isolation)
  • 1 input for Kill switch.
  • 1 input to select Timing N°1 or N°2 at startup *
  • 1 output for 12v Tachometer signal. *
  • Power supply voltage DC 6 to 18 volts (For Setup AND to operate).
  • Current drain: 30mA – 100mA.
  • Protected against reverse supply voltage.
  • 300V 8A 12pins connector.
  • 80MHz MicroController control unit.
  • Non volatile configuration.
  • Dimensions: 100 x 60 x 25mm (3.9 x 2.4 x 1inch)
  • Plastic box potted for Electrical insulation, Protecting components from mechanical shock and vibration, thermal shock or Moisture.
  • Made in France.

* Options


Pin 4 is the black mark

Half-Rectification and Common ground         Full-Rectification and Isolated ground. (More power):
12 pins Connector
HowTo wire ACCDIv12 on XT550-600
HowTo wire Sidestand & Neutral switches on XT550/XT600/TT600

HowTo setup

To program the ignition, please Print and follow this procedure: Setup Ignition box.pdf

Wifi Access Point : From version v12 and above, password is set to “password” Please refer to Setup.pdf above.

Menu Demo.

The 12pins connector has a marker trace on pin4 which is Ground.
1) Connect a Black wire from connector pin4 to the black plug of a 12v battery.
2) Wire a bridge between connector pins 4 and 6 (ground and kill input).
3) Connect a Red wire from +12v connector pin5 to the red plug of the battery to power up the ignition.
4) Led blinks 5 times while a WiFi Access Point named “Transmic_ign” show up on you laptop/smartphone.
(If a password is asked, use “password”)


* Twin-cylinders at 360° crankshaft angle:
The engine works with WASTED spark.
If there is ONE twin coil:
=> This AC-CDI works.

See: CDI compatibility


Click here for more info
A pickup (aka: VR, Variable Reluctor, Reluctor, Trigger, Pulser) is a sensor that have a signal wire and a ground wire.
It’s made of a coil of wire wrapped around a magnet.
When a ferrous part passes by the magnet, the magnetic field is modified and a voltage pulse is created in the coil generating a sine wave.

ACCDIv12 has:
– 1 input for inductive pickup (VR/pickup coil) with 1 signal per crank revolution. (Pickup must puts out 3 to 100Vac)
– 1 optional input for Digital sensor (Hall Effect Sensor, Optical sensors even Contact breaker).

This CDI works with ONE pulse per rev (1 reluctor only like “A” or “B” below)
– This CDI DOES NOT work with multi-pulse pickup (ie 2 reluctors on flywheel: “C” or “D”).
– This CDI DOES NOT work with a missing tooth flywheel. (“G”)

Pickup Polarity

Click here for more info

When the bar/magnet on the stator passes in front of the pickup, the pickup generates two pulses of OPPOSITE polarity.

A pickup has 2 wires. If you ground wire number 1, wire number 2 will put out a Positive pulse first when the rising edge comes, then a Negative pulse when the falling edge leaves. I call it PN.
If you ground wire number 2, wire number 1 will put out a Negative pulse first, then a Positive pulse. I call it NP.

Pickup Polarity MUST be Positive then Negative. to work with this CDI.

Check the polarity of the pickup (Negative going then Positive/(I call it NP) or the opposite PN: Positive going then Negative) with a Needle galvanometer (in milliAmp position) while kicking.

If the polarity is Negative then Positive(NP) then the leads are backward, just swap the wires to change the pickup polarity !

Watchout! If the pickup is internaly grounded and output ONLY one wire, you won’t be able to change the polarity.
So if the polarity is NP (Negative first) then you CANNOT use this ignition!

Pickup Position

Click here for more info

Pickup Position” is the number of degrees between the very first pickup pulse and TDC.
This ACCDI can use Pickup Position from 1 to 180° BTDC

To be able to provide the largest advance timing (Example 36° @ 4500rpm) the pickup MUST send a trigger signal BEFORE the piston reaches 36° before top dead center (BTDC).
The “Pickup Position” on the Yam XT600 is 50°. Many Yamahas have a “Pickup Position” of 72 degrees.

This “Pickup Position” is dependent on:
– Where the pickup is mechanically located with respect to TDC?
– Where is the flywheel’s bar located?
– How long is the flywheel’s bar?

Pickup Position” AKA “Max Advance” = “Base Advance” + “Flywheel’s bar Length”

“Base Advance” value sometime appears is User Manuel.
Length of the flywheel’s bar can be measured this way.

You may measure the “Pickup Position” using a protractor.
or with a caliper and some math.

Hall Effect Sensor, Points/Contact breaker

Click here for more info

Points, reluctors, Hall sensors, optical sensors can also be used as long as they give only 1 pulse per revolution. They may need an additional pullup resistor.

– 3 wires digital Hall effect sensors need an external pull-up resistor. The default voltage output is equal to Vcc (+5v to 24v). When a magnet passes in front of the sensor, the output voltage goes low and the ignition will detect the RISING edge meaning the trigger moment will be when the magnet LEAVE the sensor.

Models : Hamlin 55100, Allegro A1101-A1104, Allegro old 3141-3144, Honeywell 1GT101DC, SS495, SS49E etc…
Pullup resistor: 370ohm (270 to 1200ohm)

600rpm: 6000rpm:


Live Display of RPM vs Timing via Wifi

For diagnostic or tuning purpose, it’s possible to live view RPM and Timing in degrees BTDC on a remote PC connected through Wifi: Video
Because of the impact on CDI performance, please disable this function when you are done with it!

Ignition timing

Draw the ignition timing curve into this XLS sheet.
Example of Settings for Yamaha XT600 – 1986

Rev Limiter

The last RPM value that has been entered is the “rev limit” that stop all sparks.


Click here for more info


An output for connecting a digital Tachometer is available.
Output signal is a 0 to +12volts square signal:

Diagnose with LED.

Click here for more info
– If the box starts in RUN Mode, the Led turns ON until a pickup is detected.
As soon as a pickup signal is detected, led blinks in rhythm.
If the Maximum RPM is reached, the led turns off. If minimum RPM is reached, led turns off.

– If the box starts in SETUP Mode : Led blinks 3 times before flashing once every 5 seconds.
When data arrives via WIFI, led briefly flashes.


Transmic CDI vs Honda CDI ? Dyno speak volume:

Honda NSR125 with Malossi 180cc, Tyga exhaust, Italkit reeds tuned by “Cuco Racing Team – Spain”


Yamaha XT200 with CDI v10:

Yamaha XT600 with CDI v11:

Yamaha XT125 with CDI v11:

Yamaha TTR600 with CDI v11:

Sanglas converted from points to CDI v11:

Honda MBX 125 onboard with programmable CDI v10:

Translation of the video above

The connection to the mobile phone can be established
Various parameters must be memorized beforehand
I recommend to roughly determine the position of the sensor with a graduated disc
The stator must be labeled for a pre-adjustment with 10,20,30° marks
First try with a car battery
The positive pulse from the pickup must come first, otherwise swap the cables, otherwise the timing will be clearly wrong
So not this way !
The engine runs under 6v under its own power supply
5 degrees offset
Offset corrected
Will it go with the Vape too?

Safe settings: pickup position:70/pickup type:0/adv 0-500:0/5@1000/5@2000/10@3000/20@4000/30@6000


Click here for more info

  • Version v12r0c0:
    • Evolution of V11.
    • [soft] New menu. User can select strokes and cylinders.
    • [soft] 2 timing curves available.
    • [hard] 1 switch to select timing curve.

16 thoughts on “AC-CDI v12”

  1. Thanks for the Answer! I want the V11 so bad but from the text I took it that it sadly won’t work with 2 pick-ups, right?

    After reading the text more thoroughly, I think that two pickups should work, but I’m not sure where I can connect the second one, just to the same port as the first? (That can’t be right, can it? )
    Or do I not need two pickups at all with the programmable ignition curve and one is enough? (sorry for the spam)

    1. You took it right. ACCDIv11 DID NOT used 2 pickups.
      In fact it didn’t need the LOW pickup that sends a pulse at 12°btdc
      The cdi uses the HIGH rpm pickup at 36° to make 12° from it.

      I’m currently testing a new version of ACCDIv11r5c1 with added features (See )

      This version now uses the two pickups on XT550-600 but I haven’t got the time to write the documentation…

      1. Thank you so much!

        I think I’m slowly getting there.
        now I ask myself only the question with the wiring. I have the circuit diagram from am motorcycle, sind from the pickups come 3 cables: 12°, 36° and the pickup ground. Is said ground important or is it simply ignored?
        and what exactly is the HV cable in your wiring scheme? a brown and a red cable come out of my alternator, where do i connect them? 🙂

  2. I have purchased this excellent product for older 4-stroke motorcycles, programmable curve between 0 degrees and 38 degrees. Thank you for your help and knowledge on these products.

  3. bonjour Thierry,

    je suis motivé pour prendre la v11 pour ma xt 600 3TBK.

    Petite question suite Ă  la lecture de tes commentaires et quelques recherches :
    la version ACCDIv11r5c1 permettrait d’utiliser les 2 capteurs (12° et 36°) si je vous comprends bien.
    par contre il y’a une mofif Hardware dans la ACCDIv11r5c1 pour une deuxiĂšme entre analogique pour le capteur 12° donc.

    La version actuellement en vente serait compatible ou dois-je attendre encore ?

    Encore merci pour ton travail

    1. Bonjour et merci pour votre commande.
      La version a ce jour est ACCDIv11r6c1 donc elle integre de r5c1 une entrée pour le pickup low a 12° dans le cas des XT600.

  4. merci pour votre réponse.
    Colis réceptionné ce jour, merci !!

    DĂ©jĂ  connectĂ© dessus j’ai un petit doute quand Ă  la valeur du PICKUP
    (oui mon anglais est …. fatiguĂ©.. et malgrĂ© google traduction je ne suis pas sur de comprendre)
    en fait ces deux phrases me mette le doute :
    “The “Pickup Position” on the Yam XT600 is 50°”
    “The cdi uses the HIGH rpm pickup at 36°”
    pourquoi 50° , on a un capteur 12° et un autre 36°

    pouvez-vous svp me confirmer pour un 600XT:
    PICKUP TYPE : 0 (vr analog)

    aussi dans la documentation il n’y pas d’indication concernant SHAFT: Crankshaft ou CamShaft
    je suppose que c’est pour ceux qui on le capteur sur le haut moteur ?
    je laisse donc Crankshaft pour mon utilisation.

    Encore merci,
    hĂąte de tester sur la moto !!

    1. Le pickup de la Yamaha XT600 est physiquement placé à 50°.
      Le CDI attend un peu puis envoi l’Ă©tincelle Ă  36° BTDC.
      Les pickups sont TOUJOURS positionnĂ©s a une valeur SUPÉRIEURE Ă  la valeur d’avance maximale.
      (pour obtenir 36° d’avance max, les ingĂ©nieurs Yam auraient pu placer mĂ©caniquement le capteur a 37, 50, 70, 93° btdc etc, le CDI se dĂ©brouille mais il faut le lui dire.)
      PICKUP TYPE : 0 (vr analog)

      >je suppose que c’est pour ceux qui on le capteur sur le haut moteur ?
      >je laisse donc Crankshaft pour mon utilisation.

    2. Bonjour ,
      Je viens donner nouvelles,
      j’ai enfin eu le temps de monter le CDI sur ma moto.
      Malheureusement aprĂšs de bonnes heures de recherche je sĂšche -> pas d’Ă©tincelles.

      1) j’ai mesurĂ© Ă  l’oscilloscope je pense l’essentiel des composants (je peux faire des captures si besoin ?)
      – vĂ©rif de la tension HT du stator : OK (sinus de -150v Ă  +150v environ)
      – vĂ©rif du capteur PICKUP : OK (premier pic positif d’environ 7v suivi du nĂ©gatif Ă  -7v)

      2) j’ai enlever le faisceau elec de la moto et fait un faisceau sur mesure pour uniquement cabler le CDI tel que sur le schema “full rectification” (avec un inter pour le “kill switch” pour accĂ©der au paramĂ©trage facilement)
      – je n’ai pas essayĂ© en Half-rectification par contre.. mais je ne verrais pas pourquoi ce serait mieux

      3) batterie neuve chargĂ© ou alimentation de labo pour le 12v (avec test de masse diffĂ©rentes pour ĂȘtre sur , cadre, moteur, sur le rĂ©gul, etc..)

      4) bougie neuve, bobine neuve, antiparasite neuf (mĂȘme si Ă  l’ohmĂštre tout Ă©tait bon mais j’avais ça en stock donc autant essayer)

      -> les symptĂŽme sont :
      – sur la broche 1 (sortie CDI pour bobine) il n’y a rien : mesurĂ© Ă  l’oscillo. (bobine branchĂ©e ou non branchĂ©e)
      – la led du boitier clignote si je fais tourner le dĂ©marreur ou un coup de kick (je suppose donc qu’il capte bien le PICKUP)
      – j’ai mis une courbe d’avance simple Ă  3 points (500-8 ; 1000-10 ; 6000-30 ) , si je fais “READ” c’est bien Ă©crit comme dans la doc.

      VoilĂ , je vous avoue que je sĂšche . ça fait beaucoup Ă  lire mais je tenais Ă  essayer d’ĂȘtre le plus prĂ©cis possible. Avez-vous une idĂ©e ou une piste ? je peux bien Ă©videmment mesurer ou fournir d’autre informations si nĂ©cessaires

      En vous remerciant par avance,

  5. >la led du boitier clignote si je fais tourner le démarreur
    Donc le CDI voit bien le pickup
    >sur la broche 1 (sortie CDI pour bobine) il n’y a rien
    C’est qu’il manque la Haute Tension

    Essayez en Half rectification. J’ai vu des cas ou ca ne marchait pas en full. Surement a cause de masse non communes…
    Si besoin joignez moi directement par PM (mon adresse est en haut a dr. “Contact Me”)

    1. AprÚs des heures de recherches le résultat est tombé : STATOR HS .

      Encore merci pour les nombreux conseils et pour l’aide apportĂ©.

      A bientĂŽt j’espĂšre et bonne continuation !

    1. No. One day perhaps but surely not yet.
      To make a universal TPS input, you must deal with 2, 3 or 5 wires sensors. Sensors that go forward or backward, sensors that provide voltage, different min and max voltage or provide ohm resistance value… etc etc
      And of course a real time 3D mapping. If you need more look at Megasquirt.

      Compare Honda CDI WITH TPS vs Transmic CDI WITHOUT TPS:

  6. Good morning,

    I wanted to check the “pickup position” angle (50 degrees on my yamaha XT600) with the stromboscopic lamp.
    I set a fixed curve from 500 rpm to 6000 rpm: fixed advance 12 degrees. (and I increased the idle to 2500rpm)
    I can’t get a fix point on the flywheel. it moves a lot so very difficult to adjust the value of “picikup position”.

    I see the “TDC” mark through the hole with the strombo lamp so I already have almost 12 degrees not good

    So my question are: What I’m doing wrong or what’s the precision of this CDI ?

    (I can’t film, problem with frame rate and oil vapor projection, but I’m motivated for other tests)

    Thanks in advance

Leave a Comment

Your email address will not be published. Required fields are marked *

Shopping Basket
Scroll to Top