Engine starts, then dies, battery ends up dead

[joejohn]

Let me start by saying that my battery has died on me a few times. While trouble shooting the bike, it would slowly loose charge and I'd end up connecting it to my trickle charger over night. The next day I'd go back to trouble shooting the bike and repeat the cycle. I finally got the bike running and idling well about two days ago. I let her idle for about ten minutes, shut her down, plugged her into the trickle charger and called it a night.

Yesterday, when I went to start the bike, the battery was dead. I reset it on the trickle charger over night and when I went to start her up today she sprang to life, then the RPMs dropped, then she died. Again the battery is dead. I figure its sulfated and I'll have to replace it.

Here's where I'm a little confused because I'm getting different answers from different people.

- Would a sulfated battery cause the bike to drop RPMs and die once it had already started?

- What specific areas of the electrical system should I focus on for cleaning and would contact cleaner be corrosive to any elements of the bike?

I know you guys are probably sick of answering problems regarding the electrical system, but after reading so many threads I'm more confused than ever. I'll admit to being a little challenged when it comes to trouble shooting electrical problems, feel free to dumb it down for me.

I'm going to get the battery checked out tomorrow, and I'll most likely replace it. I just want to make sure I'm addressing the real issue and not just burning through batteries.

[marke]

The same thing happened to me when I got my bike. It's my first and I've never worked on a motorcycle before. It is most likely the alternator rotor It turns out it's a very common problem, but actually pretty easy. Here's a recent thread that has a video on how to check and replace the rotor.

viewtopic.php?f=4&t=6990

Mark E

[joejohn]

Thanks Mark. Looks like I'll be looking into that tomorrow. I also found a contact cleaner called DeOxit that should be safe for plastic, so I'll probably be spending my Sunday afternoon testing/inspecting my electrical components and cleaning every contact between my head light and tail light.

[Folsoml]

Would a sulfated battery cause the bike to drop RPMs and die once it had already started?

Yes, although I don't understand why. Mine has done it a few times.

Like Marke said, it's usually the rotor that goes bad and kills the regulator rectifier. It seems like it is a continuing process with these bikes. I'm going through the exact same problem and I've hopefully finally resolved it.

[joejohn]

Ok... Took some readings. At first my meter was jumping around all over the range, then it read open, then I had it pretty much stable between 3.1 and 3.5 ohms. There are two copper rings with some slight wear and I'm placing a test lead on each. Am I doing something wrong? My range is set to 200 ohms.

[onepieceatatime]

Ok... Took some readings. At first my meter was jumping around all over the range, then it read open, then I had it pretty much stable between 3.1 and 3.5 ohms. There are two copper rings with some slight wear and I'm placing a test lead on each. Am I doing something wrong? My range is set to 200 ohms.

If the rings are dirty, it could cause a poor connection to them from the meter leads. You also want to take a measurement on the same 200 ohm range with just the tips of the 2 leads touching each other and not your skin. That measurement will be your "calibration factor". Just the leads touching each other should be a reading of 0 ohms, any different amount is the resistance of the leads and meter and needs to be subtracted from any readings you take on the system.

[cb650]

There is also a new one 650 specific. Dont remember where i saw the link though. Might come up in a utube search.

didnt come up on a search but found the thread.
http://forums.sohc4.net/index.php?topic=112485.0

[joejohn]

Looks like I'm getting Infiniti readings on both my rotor and my rectifier. I guess I'll be replacing both.

[Mainerider]

Looks like I'm getting Infiniti readings on both my rotor and my rectifier. I guess I'll be replacing both.

Resistance readings are often inconclusive. Before spending money left and right, verify beforehand that your rotor/stator combo is actually NOT producing AC voltage. Unhook your stator harness from the voltage regulator and start the bike. Setting your multimeter to read AC voltage, check voltage between the three yellow stator leads. Put one multimeter lead on one of the yellows and the other on the other two yellows. You should see somewhere in the area of 20 volts (.full volts, not millivolts) coming from EACH of the three leads at around 4,000 rpms. If you have voltage from the three leads totaling approx 60 volts, then your alternator is not the issue. If not, then you have an issue with the stator and/or rotor, more commonly the rotor.

Also, if you dont have voltage, with the bike still running, check for a grounded stator by putting a test light on each yellow lead, while grounding the test light onto a good known engine ground (exhaust, etc.). If any of the yellow leads light up your test light you know you have a bad stator. This test helps to pinpoint whether it's the stator or rotor.

Because of their construction, voltage regulators are best tested by process of elimination; if the battery is good, if the rotor/stator is putting out proper voltage and all circuit connections are good, then the only link left in the chain is the r/r.

Again, resistance readings (especially on the r/r) using the service manual guidelines are often a waste of time, since they are tests taken in a static setting; whether an electrical component functions under actual operating loads is another story.