04 lowrider charging

Discussion in 'Dyna Models' started by low_rider, Aug 5, 2008.

  1. low_rider

    low_rider New Member

    Hello, Newbie here. I found this forum by Googling "testing a stator". I have gone thru all of the threads and find no reference.
    Anyway my wife's 04 lowrider (27k miles, stage I only) has intermittently had the HD bar n shield light come on, I ran the code and it said low voltage. I changed the battery and may or may not have cleared the code (just dont remember) anyway during our recent ride we had stopped a few times and it started up without issue. Last stop before heading home it would not start, just the sound of a low battery or loose connection. Check all connections and found them to be clean and tight, no evidence of carbon/arching. Fuel pump came on so we push started it. Tested the battery after sitting on the bench for 18 or so hours and it reads 11.7V. I would have thought that a new battery (maybe 200 miles on it) would have fully recovered after this period of time. So my question is, can I isolate/test the regulator and stator? I hate to buy both without knowing they are both bad (which I seriously doubt. Electrical is not my strong suit.
    Thanks for any advice on this
  2. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

    Check here:

    Electrical section of the self-help forums under "Testing the Charging System"

    Last edited: Aug 8, 2008
  3. glider

    glider Veteran Member

    Nice work TQ:s

    Take a look at the link below in the electrical section.
  4. low_rider

    low_rider New Member

    For some reason I can not get to the link above. When I test the stator for voltage output @ 1000rpm I get between like 16.2 and 17.5 v, is there a reason to be concerned about the 1.5 volt fluctuation? When checked for continuity it is maybe .1 ohm.
  5. glider

    glider Veteran Member

    I couldn't get thete either that way. Here's what it said...

    Step 1. First things first, load test the battery. Most places like Auto Zone will do it for free. Even if it measures over 12.5 vdc it can still be bad under a load. Battery is typically rated at 19 amp hours and 270 Cold Cranking Amps (CCA).

    Start the engine and measure DC Volts across the battery terminals, the regulator should be putting out 14.3 - 14.7 vdc at 3600 rpm and 75 degrees F.

    Step 2. To check the regulator unplug it from the stator. Take a test light and clip it to the negative terminal of the battery and then touch first one pin and then the other on the plug that goes to the regulator. If you get even the slightest amount of light from the test light the regulator is toast.

    To do this with a meter which is more accurate: black lead to battery ground, red lead to each pin on the plug, start with the voltage scale higher than 12vdc and move voltage scale down in steps for each pin. Any voltage is a bad regulator.
    You may get battery voltage on all three pins on the newer 3 phase regulators.
    The no voltage is for older type regulators with diode indicating the diode is bad and the regulator needs replacing.

    Step 3. On the other part of the disconnected regulator plug. Set the multimeter for Ohms x1 scale and measure for resistance across the pins of the stator. You should read something around 0.1 to 0.2 ohms for the TC88 32 amp system.

    Step 4. Then check for continuity between each pin on the plug and frame/engine ground. The meter needle should not move (infinite resistance)(digitals will show infinite resistance) if the meter needle does move (indicating continuity)(digitals will show some resistance), recheck very carefully. If the meter still shows continuity to ground the stator is shorted (bad).

    Step 5. Set the meter to read A/C volts higher than 30 volts (the scale setting for voltage should always be higher than the highest voltage you expect or you may fry the meter). Start the bike, and measure from one pin to the other on the plug (DO NOT cross the multimeter probes! - touch them to each other). You should read roughly 16-20 vac per 1,000 rpm.

    Step 6. If the battery was good under load test, if the stator is NOT shorted to ground, and the stator is putting out A/C voltage, then the regulator is bad (most likely even if if passed step 2).

    Generally the following is true:
    Check your owners/service manual for the system amp output for your bike.
    22 amp system produces about 19-26 vac per 1,000 rpm, stator resistance is about 0.2 to 0.4 ohms.
    32 amp system produces about 16-20 vac per 1,000 rpm, stator resistance is about 0.1 to 0.2 ohms.
    45 amp system produces about 19-26 vac per 1,000 rpm, stator resistance is about 0.1 to 0.2 ohms.

    Also see here...
    Charging System Flow chart - Harley Davidson Community