My bike's showing around 13.5 to 14 volts when running, but drops to 12 volts at idle. I know my idle needs to be run up some from 750 rpm to around 1000 rpm, but should I be seeing that kind of drop at idle? Battery seems to be okay but is over 2 years old.

 

Where are you measuring it? If at the battery, then you may have a problem. If not, could be a voltage drop in your gauge.

 

I'm just watching the gauge. Bike cranks just fine and I don't seem to have any problems. I've tried turning off lights, radio, brakes, etc. and nothing seems gets better or worse. May not be a problem, but thought I'd ask what's normal.

 

Altenator belt might be loose...... (inside joke)

 

Nah, I already checked it -- wasn't even cracked.

 

I think that a minimum of 13.5-14VDC at idle is about normal....measured at the battery....or your gauge. If your idle is a bit low for some reason, just try holding the throttle so its at about 1000RPM, and see what you get. Then rev it up to like 3000RPM and see if the voltage goes up. 12VDC just sounds too low to me.
I guess the actual specs should be printed in the factory service manual.....but the only ones I have are for a 08-Touring, and 03 Softail.

 

Should be 13.8-14.2 at 1k to 1200 rpms with the lights on. Standard format for all 12v charging systems, if you had a fan you would turn it on too. Remember at idle there is a good load on the alt with your lights on.

 

Nothing to worry about. I bet if you raise the rpm to 1000 the voltage will go back up.

 

Curious as to this.

 

Check it at the battery, perform the service checks listed in the electrical section. Don't go by your dash mounted volt gauge.