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Correct Wiring for Tacho on a Shovel

  • JustinCase
    JustinCase
    6 years ago
    Gday guys,
    So some time ago I bought a period correct oem tacho for my 1981 FXEF Fatbob shovel. At that time the seller didn't know if it worked or not. The price was right so I thought I'd have a go. 
    I'd like to change out the incorrect tacho that I've currently got to the proper one (that I bought).
    Before doing the strip down I'd like to know if someone can help me with the correct wiring in order to do a test run, on the tacho. 
    Given that there is no earth wire for the light I take it that it simply earth's out by bolting the whole unit in place, am I right?
    The rear pic shows 4 x wire fixing points. I don't have factory connection plugs, I suspect they went south years ago.

    The red circled terminal has 'TRIG' inscribed next to it. I take it that that wire goes to the top terminal on the coil.
    The blue circled terminal has ''IGN' inscribed next to it. I take it that that wire goes straight to the ignition (power source).

    My problem is I don't know where the yellow and pink terminals might go. Maybe they are securing nuts to keep the unit all together? 
    Any guidance would be appreciated. Can anyone help please?  


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  • Wideglider
    Wideglider
    6 years ago
    I think you might be right, the two other screws/nuts look like they secure the case, considering the nuts look like contacting directly to the case.
  • tussuck
    tussuck
    6 years ago
    Yellow and Pink are bolts to hold all the chit inside the unit when you remove the glass and cover.  Just leave them be.
    IGN is your power so your right there, just make sure its switched and not straight battery.
    TRIG is the pulse and is normally taken from the feeder to the coil/s from the Ignition module.  In some cases you need to install a couple of diodes setup as a "Y" if you run single fire coils vs a simple stock duel fire setup.

    PM me as I have done this a couple of times on the early Evo which is 90% a shovel anyway.

  • JustinCase
    JustinCase
    6 years ago
    Quoting tussuck on 06 Aug 2018 05:55 AMedited: 06 Aug 2018 05:56 AM

    Yellow and Pink are bolts to hold all the chit inside the unit when you remove the glass and cover.  Just leave them be.

    IGN is your power so your right there, just make sure its switched and not straight battery.
    TRIG is the pulse and is normally taken from the feeder to the coil/s from the Ignition module.  In some cases you need to install a couple of diodes setup as a "Y" if you run single fire coils vs a simple stock duel fire setup.

    PM me as I have done this a couple of times on the early Evo which is 90% a shovel anyway.

    Hi Tussuck, 
    Thanks for the advice. I may PM you if I have dramas. 
    I'm a shade tree mechanic on a good day but I'm not a sparkies a/h!!!
    Me and wires don't get on.
    Cheers.
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