Any one out there know what to check on a voltage reg to see if it is functioning good. My batt is discharging .Dose not seem to be charging.I put the load tester on the batt and it is good.Thanks Harbri

 

what do you mean, by " not keeping an electrical charge" if the battery goes dead when riding. You will need to check the charging system. start with charging the battery, and checking the battery voltage with the engine running at a fast idle. should be around 14 volts. (get back to us)
if the battery looses its charge overnight, you have a problem with the battery or a draw in the system. this can be checked using a test light. remove the negative cable from the battery and install your test light in circuit (between the negative post on the battery and the negative cable) if the test light illuminates you have a draw in the system. the most common cause is the voltage regulator. to find the draw remove circuits until the test light goes out. if that checks out, the battery is bad.
If you have the old 4 prong system, it would be best to update anyway.
The regulator is typically checked by a process of elimination. If the battery, stator and rotor check out - then it is probably the regulator.
Does your battery voltage at the terminals change with RPM (e.g. at 1000, 2000 3000)?
What RPM range do you normally ride at?
1) make sure you have a good battery fully charged AND get it load tested to be sure.
2) What is your battery voltage ready at 2000 rpm. should be ~13.8 + as previous poster said
3) Multimeter on ohms. Engine off. Check each stator pin to ground. Should be no continuity. If conitnuity, stator is grounded-no good.
3) Check ohms pin to pin. Should be around some resistance .4-.6 ohms. If infinity, then stator is shorted-no good.
4) Put to DC on multimeter. Check regular pin to ground. Should not get voltage as high as battery. If so, bad regulator.
5) Be careful on this one. Put multimeter in AC. Engine running and regulator unplug. Put one probe in each stator pin. Every 1000rpm, you should be getting a voltage reading of 19-26 volts.

Have you checked the ground for the regulator?

 

Mostly city driving here,around 3000 rpm.With reving it up,voltage dose not go up,stays at 12 12.4. I will check ground tomorrow.Batt is good,i tested it with load tester.After a lot of small rides batt goes down to 11.6 ar so,and i have to put charger,low charge on it .

 

Start going over all your connections. A bike with age will start to have connection issues. Time to start looking at all your positive and negative connections and I dont mean put a wrench on them to see if they are tight. Remove them, sand them and put them back on.

 

What year/model is it?

 

1975 sportster,shovelhead,1000

 

It's a ironhead sportster then not a shovelhead and they are two completely different bikes with completely different charging systems , your sportster has a generator so you need to get the manual for that year ( makes a difference ) and do the tests listed .

Or got over to the old Sportster section of this forum and ask , there's some sharp guys who would be able to help you wit that .

 

Thanks twist. Didnt know it was a generator. Different tests for sure. They dont put out like a stator.

 

Yeah and the 75 model still had the big old auto style regulator on it if nobody converted it to the electronic one that bolted to the end of the generator . Either his genny has gone out which they did regular or the reg crapped and I can't remember the testing for it been so long since I seen one .

 

On old Ironheads, generators have to be polarized if you have disconnected any part of the electrical supply recently.

Not sure if I remember it right...momentarily touch the Armature and Field posts after connecting power, but CHECK A MANUAL to be sure.