This morning on my ride to work I noticed that my voltage was only showing about 10.5 v so I turned off the radio unplugged the GPS and finally turned off the bow tie lights before I got my voltage back to 12.5 - 13 volts. It was a little hard to start this morning too. I had changed my oil on Saturday after I had noticed that my oil pressure was all over the map but that may have had more to do with the temp than anything. When I started the bike to coat I saw that I was running at 10.5 volts then too. A while back one of the bow tie lights went out and instead of going to the stealer for a new one I went to the local NAPA and got new ones that are really tractor lights but the specs were really close so I don't think that was it. Any thoughts? Oh and yes I did some searches on the forums before posting and wasn't finding anything that pertained to my issue.

 

Sounds like youre just running off battery voltage. Correct charging rate on a 12v system is 13.8 min-14.2 sometimes up to 14.8 on newer vehicles. If you never had an issue before changing your oil, check the stator plug just under the oil filter, you may have loosened the connection or got some oil in there making a bad connection.
On a 98 vintage bike the voltage regulators went out, I had a 99 and replaced it 2x in 35k. Also check all your battery/stator and ground wire connection

 

I found this http://www.hdtalking.com/electrical_...ng_system.html

Also see here...
Testing The Charging System - Harley Davidson Community

Charging System Flow chart - Harley Davidson Community


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.

 

If I was you I'd first start checking connectors for being loose or corroded, especially the battery.

I was having a similar issue. Replaced the stator / rotor with an upgrade from 22 amps ('86) to 32 amps. I still needed a fresh battery and a regulator to overcome the issue.

Just to aid the recharge voltage issue at an idle while stopped, I replaced several bulbs with LED which also helped on the heavy drain on the battery when braking, using 6 bulbs for brake lights.

 

Thanks all I will be putting my meter to it when I get home tonight. Trackadapter thanks for the detail that is really helpful.