1989 FLCTU electrical issue(s)

Discussion in 'Electrical' started by cruiser66, Aug 15, 2010.

  1. cruiser66

    cruiser66 New Member

    1989 FLTCU electrical problem(s)


    Bike displays the following: when using directionals or brakes, volt meter spikes down and tape cassette/instrument backlighting dims. Also after starting engine and then shutting off heard starter bendix spin down. In addition, hear stactic/feedback through rear speakers, when using directs/brakes.
    So far have:
    checked all light grounds, added two additional grounds (one from frame to starter mount bolt and one from front of frame up to grounding block under instrument cluster). Changed out starter relay. Also have disconnected starter wiring from starter (connected batt pos cable and lead that share starter post together, but removed from starter post, to remove starter from problem. Still have same initial sympthoms. Any ideas/direction> Thanks
  2. Hoople

    Hoople Account Removed

    Sure! I am loaded with ideas on how I would do it.:p

    You have to establish a few known good items first,, such as battery condition and charging system output. It does not matter if the battery is just a year old. Load test it to 1/2 it's CCA for 15 seconds and see if the voltage drops below 9.8 volts. If you don't know the CCA, I would go with something like a 140 amp load for 15 seconds @ 9.6 volts.

    Then use a quality voltmeter across the battery to measure your charging system output at idle, and at a steady 2500 RPM. You have to get some concrete numbers and at least establish if the battery can and will hold a charge that is sent to it by the charging system,, and exactly what that charge is.

    Once you PASS both of those tests, you will know where you stand and can move on to voltage drop tests on those nasty trouble causing items like circuit breakers..:s which I am sure you have a few on your bike.