Voltage regulator.

[Name Etc.]

measured 0.3 ohms with a 4 wire sense Ohm meter from battery terminal to the Frame bolt down by the footPeg. I would say it isn't a ground issue. I pulled the Main Fuse cleaned the terminals with a glass fiber brush. I got .1volt but still a volt drop when I Flip on the driving lights or Heat Jacket. Still investigating.

[Name Etc.]

Over on that other forum....dcarver has a great thread about his charging system troubles. The condensed version is: The RR wiring is barely adequate.

After I added a volt meter I was disappointed to only see 13.8 on a good day. This was before adding heated gear or lights.
Anyway, Jack over at Roadstercycle (http://www.roadstercycle.com/" onclick="window.open(this.href);return false;) offers an upgraded RR harness for our bikes. The price is fair, delivery is fast and Jack was a pleasure to deal with.
It got mine up to 14.2 (sometimes 14.3). As an added bonus, the leftover wiring is perfect to power a fuzeblock under the seat.

After disassembling the bike, I was unable to fix this low volts... I did get a 13.9 and a peak at 14.0 once. I looked up connector prices and wire and 50 amp breaker. Jack is reasonable and it fixes the problem. Got it yesterday and plugged in the wire strung across top of bike screwed to battery. Boom 14.2 running my hella lights and the 105 watt jacket full blast dropped volts at battery to 13.9 better than the previous 13.0-13.1 or worse with lights and jacket,,, wire size... Guys size does matter. It's ten gauge instead of 14.

[Chuck35]

Glad to hear you got it sorted out