Tach problems

Discussion in 'Electrical' started by leadhand, Aug 9, 2010.

  1. leadhand

    leadhand New Member

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    I have a 67 FLH with a 73 shovelhead engine and 80inch top. Still has points. I just installed a speedo tach combo and got most of it working. The tack is flutering all over. I have done a tuneup (points condencer plugs and even the timing). I put my digital timing light on the bike ( both jugs) to see if it was the speedo tack combo and it looks like it is something else. Any ideas?
     
  2. Jack Klarich

    Jack Klarich Expert Member

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    Possible the tach is not compatible with your coil? Is this a Harley tach speedo combo?
     
  3. leadhand

    leadhand New Member

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    It is a V-twin speedo-tack combo. The coil and plug wires I will change this weekend to see if this fixes the problem.
     
  4. Hoople

    Hoople Account Removed

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    You are giving people like myself nothing to work with.
    You have a '67 with a '73 engine and your avatar says your a 2003 (injected Magnetti Morelli ECM), but yet your bike is points triggered,, and the speedo tach assembly came from a V-Twin which I will assume had a module to drive the tach.( maybe? would help to know)

    If I understand you correctly, your taking a tach/speedo that came from an ECM (or at least an ignition module) driven bike that had conditioned signals on it and your trying to drive it from the negative side of a points system/coil? Does your present "points" system drive an ignition module, or are the points just going to the negative side of the coil.

    If your points are currently connected to the negative side of your coil, changing the coil & wires probably is not going to buy you anything. I would not keep hitting that tach with pulses from the negative side of your coil. I would take much of that.
     
  5. leadhand

    leadhand New Member

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    I have two bikes. The one with the trouble is my 1967 FLH with points and the tach is a speedo-tach combo that cam from the company V-twin after market. this is designed to work with points and negative side of the coil.
     
  6. Jack Klarich

    Jack Klarich Expert Member

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    Check your advance mechanism