First, connect a voltmeter to your battery and see what the voltage is before you start it. Then start the bike - the voltage at the terminals should increase to something above 13 VDC with the engine running. If it doesn't change or drops, you might have a charging system problem.

If you're not seeing an increased voltage, I'd check the charging system (stator and voltage regulator).You can perform a forum search to find the details, but basically you have to get the bike running and unplug the voltage regulator and check for AC voltage at the plug. You should read ~70 VAC if it's working properly.

If you perform these tests, at least you can verify that the charging system is functioning. Good luck.

 

^ what he said.

I was just about to suggest that it might be the charging system, and you should definitely check that first.

Let me shed some light on this potential issue:

My sportster was doing the same thing. I too thought it was the battery at first, but it wasn't. I ended up buying a new battery to figure that out... Then I thought maybe it was the starter, but it wasn't. After talking to a motorcycle mechanic, he suggested that it was probably a bad charging system, and after reading up in the factory manual about it I determined he was definitely correct. Further investigation by me discovered that there was an excessive drain on my battery. It was being caused by my headlight. I now have it unplugged at the base and everything works fine like it should. I still don't know how to fix it yet, as I have to hunt down the wires and figure out where the short is. I'm not looking forward to that... At least I know for certain what the problem is now though, and I can drive somewhere without having to worry if it will start back up or not (it didn't once before I knew what was wrong).

To test for excessive drain, I just unplugged the fuses one at a time for the lights and instruments (which were the middle two for my model) and then tested the regulator each time at the battery to make sure it was charging right. I determined it was the lights, then I unplugged my headlight from the base, and everything works fine now.

 

Yes, I will be checking to see if the battery charges once I get my hands on a voltmeter from my neighbor. If it is a bad stator or regulater, wouldnt my bike not run at all?

Shackleford, Do you not ride at night then?

 

No, if you have charged battery, the bike will run until the the battery drains down to a low enough voltage that either the ignition quits firing or the ECM shuts down do to low voltage. Just prior to the motor shutting down, you'll typically get a Check Engine and Battery light indicating a Low Voltage condition. A Low Voltage diagnostic code will typically also be stored.

If the charging circuit is working properly, you should read between 13.5 - 14.8 volts DC across the battery terminals, with the motor running at a Fast idle (~2,000 rpm).

 

Right now I don't!

 

stator. its a suck-job too.

 

So I hooked up the voltmeter to it and it was 12.5 volts off. Turned it on and it went to 14.1volts rev'd a lil and it stayed at 14.1 v. Kept it rev'd for a bit and it went to 14.2 then back to 14.1. Then I left it idle and it stayed going back and forth between 14.1 and 14.2. Finally cut the engine off and it slowly went down to 12.7 where it stays now. So what's the outcome?

 

That's good, that means your charging system (stator and regulator) is OK and you're not looking at a $400.00+ stator replacement.

What exactly are the symptoms now? Is the motor not turning over in the morning? Turning over sluggishly? In warm and cold weather conditions?

 

As of right now it's turning over fine, I even just went for a ride to see if I'm draining the battery and came back shut her off and checked and I was getting the same reading, turned her on just fine. It's 71 degrees here now and not 20 degreese or 40 degrees when I'm having the problems. This weekend it was under 50 degrees all Sunday ride and each time I shut her off to stop somewhere and then get back on her she was sounding weaker and weaker, until I rode her for 45 min on the highway and the sun peaked out and I didn't seam to have problems with her from then on. But it worried me so much that's why I got te battery tested yesterday. Maybe the fact that I removed it and re-installed it fixed the problem. Maybe I had a loose bolt? I used loctite on one bolt that was a little loose in the threads. I will take the meter with me and ride her to work tomorrow. Question right now is should I hook her to a tender for the night? She is reading 12.6 volts right now

 

It never hurts to use the Battery Tender. It's not necessary if you're riding it regularly, but I plug mine in every night.
Also, on average, it takes about 20 minutes riding at cruise speed to recharge the battery (replace the power used) after each motor start-up. Numerous short runs in stop & go traffic with frequent restarts can cause you to wind up with a low battery.