I ride a 1991 Ultra. I had the stater replaced last fall. Last weekend I noticed while riding with my headlight on the battery discharges so low my directionals don't work. If I ride without the lights on the battery maintains a full charge. Any guesses?

 

Short?

 

+1

that's where i would start

 

That's where I'll start. Thanks for the replies.

 

Ok if it was a short not only would the amp gauge be to the minus side of zero it would prolly blow a fuse.. Is suspect a bad or weak charging system component before id call short.

 

+1 A battery on a full charge will last a while without lights. Turn on the lights, it's going fast. Pull the seat, run the bike and put a voltmeter across the battery. You can look in the manual for the exact numbers but you need to be getting 12+ volts at the battery, usually more in the 13-14 range. You can usually tell right away if you give it a little throttle, there will be a small increase in voltage. If not, time to figure out if it's regulator, stator or rotor. If the charging system is ok, which I doubt based on your symptoms, all that is left is battery and wiring. The battery can be load tested at any battery center or your local, friendly HD dealer.