Insane, growing, electrical problem

[OldNTired]

Hello, all. This is my first post, so if I get something wrong please let me know.
I have a 2006 GZ250. At the end of last year it 'looked' like I had a battery problem. Since it was the end of the riding season I didn't get serious about it, all I did was test the battery, and test to see if it was charging. After 1/2 hour of riding it measured 11.75 volts at rest. BUT, when I tested it while the engine was running, the voltage jumped all over the place! The highest 'charging' voltage was about 11 volts, the lowest was about 6.5. The worst part was that I got the lowest voltage at higher RPM's. It finally warmed up enough today to try to check it out. I thought at first that it must be the rectifier. I can not get consistent readings on the rectifier tests using a diode tester. I tried two different meters! Checked out the stator, etc, it looks fine from what I can see (checked OHMS).
No, there were no loose, corroded, burnt, or pinched wires, anywhere that I looked.
But, here is the worst part! I figured I'd put it all back together to make sure nothing got damaged from sitting around. Then, just for laughs I thought I'd test the charge while it was running, just to make sure. But, I got nothing when I turned the key: no lights, no horn, no T signals, no starter, not even a neutral light, nothing!
From reading every post I could find having anything to do with the rectifier, I did see that some folks have had problems with the wiring inside the headlight bucket. I will check that out soon. But, would anything in there cause the erratic charging?
I am at a loss here, any help will be welcome. And thanks in advance. I would add a 'confused' smiley here, but can't figure out how to do it!

[Road_Clam]

Couple questions, when you're checking output voltage was your engine at idle ? You should always bring the engine rpm's up to about 4000 rpm's then take a voltage reading. You need to be about 14.5V . Also when you check a freshly charged battery you need to be about 12.4 v. All your #'s seem to be low . As for your system just dying and no power anywhere, you could just have a bad ground. Bad grounds are a very common problem to electrical gremlins.

[OldNTired]

Originally Posted by Road_Clam

Couple questions, when you're checking output voltage was your engine at idle ? You should always bring the engine rpm's up to about 4000 rpm's then take a voltage reading. You need to be about 14.5V . Also when you check a freshly charged battery you need to be about 12.4 v. All your #'s seem to be low . As for your system just dying and no power anywhere, you could just have a bad ground. Bad grounds are a very common problem to electrical gremlins.

Thanks for the reply. I thought I answered this though, maybe I wasn't very clear. And, I forgot to mention that over most of the winter I kept the battery on a tender.
Anyway, I did test it at high RPM's, I could have written it clearer, but I did say that the voltage was lower at higher RPM's. At idle it was about 11 to 11.5V, at about 4000RPM it drops to about 6.5V.
The battery was at 12.8 off of the tender. I know it needs to be 13.5 to 14.5V when charging, that's half of my problem and the reason I was checking out the rectifier.
You might very well have an idea with that question about a ground, but wouldn't that have drained the battery while it was sitting? I don't know. It stayed at about 12.6 all winter, I put it on the tender when the temps got really low around here. It is in a garage, but not a heated one.
Any ideas where I might look for a short? I've trid eveywhere but in the headlight bucket.

[Water Warrior 2]

First things first. Make sure the battery post are clean and connections are tight. Also check for a frayed wire in the headlight while looking in there as a bit of vibration can do ugly things to wires and connectors.
I don't think this will help but I once had a rectifier give up on a 750 Suzuki. The system would only charge at high RPM. This is the way it was explained to me by a tech who fixed it. The low end/circuit was shot. Sounds like your's is doing the opposite. Maybe the high end of the rectifier is not working.

[OldNTired]

Originally Posted by Water Warrior

First things first. Make sure the battery post are clean and connections are tight. Also check for a frayed wire in the headlight while looking in there as a bit of vibration can do ugly things to wires and connectors.
I don't think this will help but I once had a rectifier give up on a 750 Suzuki. The system would only charge at high RPM. This is the way it was explained to me by a tech who fixed it. The low end/circuit was shot. Sounds like your's is doing the opposite. Maybe the high end of the rectifier is not working.

Thanks.
Yep, the battery posts are clean and connected well.
And, like you said, every time I've seen a voltage regulator or rectifier go bad it only worked at very high RPM. I guess I'm just lucky.
Seems like everything, and everyone, keeps going back to the headlight for the 'no power' problem.
That will be the next thing I check. Might not have time tomorrow, or even the next day, but will get to it as soon as I can.
I guess I should add some things I didn't before. All fuses were checked, all connections (not counting inside the headlight bucket) were checked.
Kickstand switch was checked.

[Water Warrior 2]

Looks like a process of elimination to find the problem. Carry on and good hunting.

[OldNTired]

Originally Posted by Water Warrior

Looks like a process of elimination to find the problem. Carry on and good hunting.

Yeah, thanks. I was hoping that someone had the same, or very similar, problem of the charging voltage dropping as the RPM's went up. You are right, without a real clue the 'no power' problem will just be trial-and-error until I find it. It might take a while, one thing I don't believe in is replacing parts just to see if it helps without knowing that they are bad. :??: It's gonna be a long week.

[Water Warrior 2]

Originally Posted by OldNTired

Yeah, thanks. I was hoping that someone had the same, or very similar, problem of the charging voltage dropping as the RPM's went up. You are right, without a real clue the 'no power' problem will just be trial-and-error until I find it. It might take a while, one thing I don't believe in is replacing parts just to see if it helps without knowing that they are bad. :??: It's gonna be a long week.

Dealers just love the trial and error routine. You get to make their house payment for them.

[Road_Clam]

Originally Posted by OldNTired

Thanks for the reply. I thought I answered this though, maybe I wasn't very clear. And, I forgot to mention that over most of the winter I kept the battery on a tender.
Anyway, I did test it at high RPM's, I could have written it clearer, but I did say that the voltage was lower at higher RPM's. At idle it was about 11 to 11.5V, at about 4000RPM it drops to about 6.5V.
The battery was at 12.8 off of the tender. I know it needs to be 13.5 to 14.5V when charging, that's half of my problem and the reason I was checking out the rectifier.
You might very well have an idea with that question about a ground, but wouldn't that have drained the battery while it was sitting? I don't know. It stayed at about 12.6 all winter, I put it on the tender when the temps got really low around here. It is in a garage, but not a heated one.
Any ideas where I might look for a short? I've trid eveywhere but in the headlight bucket.

OK, now i'm thinking you have a bad "phase" in your stator output. d/l the factory service manual and go to section 6-8 and do the ohm, and "no load" tests for your stator. If your stator checks out then the only component left to be faulty is your R/R .

[alantf]

From your description of the fault, it's possible that there's a problem with the silicon control rectifiers, which control the charging voltage.[attachment=1:1naghzuo]img042.jpg[/attachment:1naghzuo][attachment=0:1naghzuo]img036.jpg[/attachment:1naghzuo]