I'm a new owner of a '97 1200 sportster. It seems my bike is not charging the battery while enginge is running. I've used multimeters before just not very much. I charged my battery fully and it reads at 12.7 volts. When I start the bike its at about 12.4 roughly. Ive been reading Dr. Hess's charging post and when I rev the engine the volts don't change. When it comes to reading ohms and ac voltage I'm not familiar enough to know if I need to move the wire positions on the multimeter itself or leave them where they were when I was checking the voltage. And I'm not absolutely sure where to set the dial on the meter either. I just wanna go ride and don't wanna be sitting somewhere with a dead battery when I go to start my bike. Any help would be greatly appreciated. Thanks

 

I'm not as familiar with sportsters, but returning from Sturgis, my engine light came on [2009 FLHX]. Voltage indication was low, and I was not -that- far from home.

When I said f--- it and rode on, I had 2.5 hours to go. Amazingly, the voltage dial climbed, and the battery was charging once again. This magic only lasted 20 minutes. A spirited pass -- and the voltage dropped off; again.

I made it home and parked my motorcycle on the lift. I knew the battery was an issue, so charged it, and did a load test. It failed. As well the positive terminal was hot, indicating battery internal resistance.

I bought a new battery, a proper, expensive, AGM HD Battery. Installed it, trickle charged it to ensure 100%, and went for a ride.

20 Minutes later, the engine light came on -- again.

Stator or regulator...

I checked and had appropriate phase to phase resistance, but not the appropriate phase to ground resistance. Shorted to ground - I found the issue; the stator.

Took the primary cover off, pulled the primary chain, compensator, and fought to get the rotor off. Once off it was clear. The stator coils insulation was clearly burnt.

Since the Canadian dealers charge an arm and a leg [$430] for a stator, I got pricing for a stator and regulator in the USA [$370 - stator & chrome regulator].

The stator replaced in an afternoon, and the regulator was replaced for some chrome, but more to ensure the entire system was 100%.

So - in your case, the three main components in the charging system are potential failure points. Pull the battery, and have it load tested. Check the stator - multimeter on ohms. phase to phase [between the three pins] you'll want 3-10 Ohms. Then check each pin to ground [chassis]. You'll want the Ohm value to read >100 kOhms. It might read over range. If it is anything less than 5000 ohms, I'd consider changing the stator.

If the stator checks out, I'd move onto the regulator. Connect the stator, and disconnect the positive regulator connection to the battery. If you have the battery charged, put the motorcycle in neutral, and start it. See if the voltage is a stable >13 Volts. If you happen to have a DC Clamp meter, you can check the amperage charging the system.

Best of luck. If you don't feel comfortable doing any of the previous mentioned steps, I hate to say it, take it to a dealer or independent shop.

Very likely the battery is toast. I hear they give up after the heat of the summer and the vibration of the motorcycle after 4-5 riding seasons. Mine lasted 6 riding seasons... You could just try a new battery.

Best of luck.
H

 

Well I just left the auto parts store and my battery is fine. What did you mean by "between the three pins"? If you are talking about the pins on the stater plug mine only has two. My only concern is making sure I have my meter on the right dial setting

 

Gentlemen, we have two Stickies at the top of this section which deal with checking your charging circuit! They should help you diagnose where your problem lies.