Last fall, my '09 Fat Bob FXDF with 7800 miles on it decided not to start one day. It showed the dreaded check engine and battery lights on the dash. I put it away for the winter and just got time to screw with it today.

I've installed a new regulator and it has a new battery.

It starts OK and runs, no lights on dash, but it's only charging at 12.16 volts at idle, and that goes to 12.17 when RPM is raised.

Thoughts?

Stator?

Tests?

Thanks!

 

have you checked to see if any codes are stored?

 

No, didn't check for stored codes.

 

That sure sounds like a stator/regulator issue. Whatever it is, it is not charging at that voltage. Those numbers are low for a battery even when the bike is off.

 

+1
I have 12.7V with the bike off (just ignition switched on).

 

First check fuses.
Check for codes
Then recheck battery with the engine off and then with it running.
Take a short ride and recheck.
It does sound like a stator problem.

 

Also check for loose or corroded contact point. The ground terminal on the bike is a common one.

 

Sounds like stator. No need to check codes, obviously it has codes, obviously its not charging, obviously the codes are for no charging. Here's how to check the stator. Unplug the stator. Trace the wires from where they come out the front of the case, there will be a connector near the regulator, you unplugged it to change the regulator. On the stator side, the wires coming out of the case, you have to check ac output. Set your meter to ac and between any two of the pins in the connector you unplugged, check voltage with the bike running. Should be around 20 at idle and raise 10 volts per 1k rpm. Another test you can do is simply check for continuity between all the pins at the same connector to check for an open. Finally you can check for continuity to ground at all the pins to see if the stator is grounded. Three very simple tests that will tell you exactly what's going on.

 

Thanks vdop, I'll check those connections and voltage. Appreciate the help!

 

I checked the tested the connections and have found that the stator is the problem.

Before I tear into this project, does anyone know the size of the compensator nut on an '09 Twin Cam? I've researched this and the seem to be several answers. Thanks!