Electronic ignition to points conversion

Discussion in 'Airheads' started by TJ530, Jun 12, 2019.

  1. Big Bamboo

    Big Bamboo Aircooled & Sunbaked Supporter

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    The condenser is attached to the outside of the can with a screw as shown. Its base holds the block with the two connectors, one for the points and one to the wire for the ignition/coil: [​IMG] [​IMG]
    #21
  2. WRC51

    WRC51 Long timer

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    The drive on the above bean can looks just like the drive on a VW distributor.:D
    #22
  3. Big Bamboo

    Big Bamboo Aircooled & Sunbaked Supporter

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    Yep, basically the same thing. Did Bosch build the original bean cans?
    #23
  4. bmwrench

    bmwrench Long timer

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    Yup. I have never reapplied heat sink paste to one of these, and I can't remember the last one that failed, even when using the lower resistance upgrade/replacement coil.

    OEM EI last a long time, frequently for the life of the motorcycle. In my experience, aftermarket stuff doesn't. In some cases, it's worth the risk of failure. My Triumph Trident is one of those cases, and I think 70-'78 Airheads are another.
    #24
  5. Warin

    Warin Retired

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    Still using a gray 'crakomatic' coil .. from 1980... Along with the ICU - original paste.
    (I do carry spares)

    If they could make the rotors that 'unreliable' I'd be very happy. :1drink
    The HES I can deal with for $30 every 10 years or so - replace before it fails.
    #25
  6. TJ530

    TJ530 n00b

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    Anyone know what thickness wire I should be using between the points can and EI module?
    #26
  7. Warin

    Warin Retired

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    It does not carry much power - so any thin wire will do. You can use a thick wire .. but that is a waste of copper.
    #27
  8. TJ530

    TJ530 n00b

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    Just wondering about the circuit diagram that 190E has posted , I will be using a single dual output 3 ohm coil and the diagram shows 2 coils.
    Is there anything that I need to know in regards to variances between the two formats?
    #28
  9. Warin

    Warin Retired

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    None.

    The spark plug leads got to the big terminals.

    One of the small terminals goes to the battery (could be labeled + and/or 30) through the engine kill switch (if you have one) and onwards to the ignition key switch.
    The other terminal goes to the points (could be labeled '-').
    #29
  10. 190e

    190e Long timer

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    If the coil has terminal markings for polarity then fine but most dual output coils have no polarity because they fire one plug centre electrode to earth strap and the other plug earth strap to centre electrode. If there are no terminal markings don't worry about itas it makes no practical difference which way around you connect them.
    #30
    Warin likes this.
  11. TJ530

    TJ530 n00b

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    Thanks for your replies, I was reading somewhere about a chap who broke down and had to fit a points can to his BMWR100GSPD and there was some problem where the condensor wire started to melt , there was a comment " it is simple one wire from the black wire side , your good. From the green wire side your toast" Im still hoping that out of this I will end up with a diagram to match the coil that I will be fitting.
    Just wondering is it possible to get the points bean can 180 degrees out if not fitted correctly?
    #31
  12. UnclePete

    UnclePete Been here awhile Supporter

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    ….Just wondering is it possible to get the points bean can 180 degrees out if not fitted correctly?....

    The drive slot is offset so it can only be installed one way .
    #32
    WRC51 likes this.
  13. Plaka

    Plaka Brevis illi vita est

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    the coil will set the draw across the points. too mu7ch draw and the points will burn.

    as mentioned, offset key. it ony goes one way.
    #33
  14. Disston

    Disston ShadeTreeExpert

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    Not only is the interface keyed so the cam only goes on one way but 180 degrees off would still be timed right in an Airhead motor.

    BMW did not have to make the interface eccentric. Or did they? I think they didn't. Maybe I'm missing something?
    #34
  15. Plaka

    Plaka Brevis illi vita est

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    you are missing something. the can has to be adjusted. 180 out and the adjustment slots would be limited. a points setup has two lobes on the cam working the points. it fires twice per 180, not once. set up the points plate 180 out and you have no slot.
    #35
  16. Solo Lobo

    Solo Lobo airhead or nothing Supporter

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    You can’t install the can 180 out, the drive is by offset key
    #36
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  17. Plaka

    Plaka Brevis illi vita est

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    is there an echo in here?
    #37
  18. Warin

    Warin Retired

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    Could well be a 'standard part' from some parts supplier. Like nuts and bolts, best to use 'standard' parts.
    #38
  19. Kiwiabbo

    Kiwiabbo Been here awhile

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    Something appears to be missing here. So to go forward we need to go backwards. I very much doubt there is a modern motor running points, let alone all the electronic conversions of older motors. We have a whole lot of different versions out there and are we saying we can’t trust any even though a lot have been proven to do the miles. I have a points can sitting on a shelf and there it can sit. Reading this thread, it could be worth more than gold in a few years when everyone throws away their current electronics and goes back into the dark ages.
    #39
    Jim K in PA and Warin like this.
  20. Disston

    Disston ShadeTreeExpert

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    Yes the cam to ignition points can is eccentric so can only be installed one way. But I am saying there is no purpose for this feature and the interface could have been made with ability to mount the can either one of two different ways being they would be 180 degrees apart there would be no difference.

    So my question is why did BMW do this if it was not needed?
    #40