Black Wire Sensing Voltage -
Hey Sunburn - The Voltmeter on my 1200 GW will (very briefly) read +14.9 volts while at highway speeds but usually shows +13.5 - 14.2. How long does your bike's voltage read high and where is your test point ? Do you have a wiring diagram on your bike ? To help you troubleshoot your Voltage Regulator - Below is a simplified diagram and overview.
There are Three Yellow Wires (bottom Left Corner) coming out of the Stator Winding (Locatd Inside Rear Engine Cover), each wire produces an AC voltage that is rectified to DC and used to charge your battery and power the bikes electrics. The Red/White Wires (Upper Left) carry the rectified (DC) OutPut Voltage. The Green Wires (Bottom Right) Grounds the Regulator. The Black Wire (Upper Right Corner) is the Voltage Regulator "Sensing" input that tells the VR the Bikes Wiring Voltage. (Not Battery Voltage).....
If you are reading your bike's voltage at the small fuse box located on top of the air cleaner - it will read slightly LOWER than the voltage read directly across the battery (+/-) terminals. The difference (1-1.5 volts) is the result of losses in the (30 Year Old) ignition switch contacts and other wiring connections throughout the bike. The VR looks at the bikes wiring (Not The Battery) Voltage for it's sensing point. Depending on the Resistance within the wiring harness, the VR will sometimes temporarily flare it's Output Voltage higher than normal. Naturally if the VR holds the Voltage near +15 Volts continuously there is a problem and it can damage the Stator Winding and the Battery.
A good VR Performance Test is to jumper the "Black Sensing" wire directly to the battery, if your voltage reading is still over charging - your regulator is defective.
Good Luck - Michael
Last edited by JK McDonald; 04-01-2019 at 05:33 PM.