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Discussion Starter #1
I am diagnosing a dead battery and found out the following:

Battery (new) is at 12.8v
Started up, voltage remains at 12.5-12.6v
Yellow wires from stator are .6ohms between each other and are not grounding
Wires to rectifier check out OK per svc manual

However, my battery drain while off is .280ohms, which is a little out of spec, but the book immediately suggests
The rectifier is bad. Any assurances from anyone out there before I drop 50-100 bucks on a rectifier?
Anyone know where I can get one in Los Angeles before my planned Sunday ride?

Thanks for any help-

RuZ
 

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Well, with my xp in the auto world. Your diag flow chart is pretty close to being dead on. Your alt seems to be doing its job, by the readings I see. Cars should sit around 13v but this maybe diff. Do you have any acc on your ride? (PC, lights, ect...) You may wanna see what Subsailor has to say on this matter.
 

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You should be getting more than 12.5V with the engine running.
The manual says check the voltage at 5K RPM.
It should be less than 15.5V, but more like 13.5 to 14.5V usually.
It takes at least 1.5V above 12V to charge a battery.
The manual says the alternator charging coils should be .2 to .5 ohms at 68 Deg F.
Battery should be around 13.0 to 13.2V fully charged, and needing charging if below 12.3V.
Current leakage test using Honda's test unit should show .1mA max.
 

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Discussion Starter #5
I spoke to the seller of a "2002-2003" stator in Missouri, he agreed to overnight it to me. Should be here today :D

$30 plus $27 to overnight it. $57 ain't bad.

Thanks for the input-


RuZ
 

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Discussion Starter #6
Got the new rectifier in today. Unplugged the old one, plugged in the new one, fired 'er up. Same thing. CRAP!!!

Sitting voltage 12.6v
After started up, it fluctuates from 10.9v to 12.3v depending on the speed of the motor.

So now what? The stator is within spec, the rectifier is replaced with a known good unit, the battery is new. Is there something I am missing? Sunday isn't looking too good.

Is there a chance the device that spins around in the center of the stator, inside the engine cover, is bad or corroded?

Thanks in advance-

RuZ
 

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Discussion Starter #7
So going back to the .286ohms leakage, i followed the instructions of the service manual and began unplugging components one at a time to determine the cause. I pulled the odometer fuse on the left side fairing and the ohms dropped to 0. So I plugged it back in and worked my way up the odometer harness, nothing, nothing, nothing, unplugged the odometer, wham, ohms went back to 0. Plugged it back in, ohms went up to .286.

Does this mean anything? The odometer had been modified with the blue LEDs by the previous owner.

-RuZ :confused:
 

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It may be possible the LEDs are causing this.
Depending on the way the meter leads are connected, you may be forward biasing the LEDs and altering your reading.
Can you disconnect the LEDs to see what effect they have?
 

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Discussion Starter #9
I disassembled the odometer today at work and the replacement LEDs are hard soldered onto the circuit board inside the cluster. I got to thinking, though, even at .28xOhms would it be significant enough to cause a 2-3v drop in charging power? I am thinking I might have a failure somewhere in the stator region.

I'll be sure to post my results in case someone else has had this happen.

RuZ
 

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I disassembled the odometer today at work and the replacement LEDs are hard soldered onto the circuit board inside the cluster. I got to thinking, though, even at .28xOhms would it be significant enough to cause a 2-3v drop in charging power? I am thinking I might have a failure somewhere in the stator region.

I'll be sure to post my results in case someone else has had this happen.

RuZ
Sorry, I thought you were talking about aftermarket illumination LEDs for the body work, not the instrument panel
The alternator is just a three-phase unit that sends to the rectifier/regulator unit. You should be able to measure specified resistance across each coil, and to ground. Should be .2 to .5 ohms.
 

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Discussion Starter #11
So if the wiress test out at .6 or .7 Ohms between each of the yellow leads, does that mean the stator is toast?

RuZ
 

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The specs say .2 to .5 ohms at 68 Deg F.
So if you you're getting .6 to .7 ohms, then it does appear to be out of spec.
Is this across every coil or only across one coil?
Hypothetically, if the alternator coil resistance is high, then less current is being produced, and less current to charge the battery or run the bike.
You stated this previously, but to clarify again, when you have your bike at 5K RPM (the recommended RPM), what does a voltmeter show across the battery contacts?
You should see more than 12.3V. More like 13.5 to 14V (but less than 15.5V).
And you changed your rectifier/regulator unit, so that's not the problem.
 

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Electrical problems

I had similar problem and I replaced the stator before rectifier and bought new scorpion battery. I have added red leds all over bike have a pic uploaded and I have not had anymore problems with bike.
 

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Discussion Starter #15
Just to double-check my observations, I re-checked the stator resistance, and found the following definitively:

Resistance between wire 1 & 2 : .2ohms
Resistance between wire 1 & 3 : .4ohms
Resistance between wire 2 & 3 : .3ohms

I removed the stator cover to inspect the stator and it seemed fine, no breaks in the wires or insulation, no junk floating the the oil that collected in the bottom of the cover (maybe an ounce or two...)

So I am at a loss. Is it possible I replaced a bad rectifier with another bad rectifier? The replacement was off of a known-good running bike. Crap.

Crap!!!


-RuZ
 

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Was the rectifier known good to you, or was this info supplied by the seller? Just asking. It's possible he was unaware of a bad unit himself.
 

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Ok it appears that your stator coils look good.
Another thing is to double check is the condition of the connectors and terminals of the charging system.
Make sure your battery posts are not corroded and the contacts of the regulator/rectifier connector. Also check your frame ground connector on the right side.
I know when I was replacing my wiring harnesses (another story) I noticed some of the contacts were corroded. That's why I coated every connector with dielectric grease.
 

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Let me check my system tomorrow.
I'll check my battery voltage level, and then crank the engine and once warm, I'll check the charging voltage at the prescribed 5K RPM.
I may also do the battery current leakage check too.
At least you'll have some comparison feedback.
 

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Discussion Starter #19 (Edited)
Bizarre.

Ok, well, I thought while I had the stator cover off, I'd clean up the
Little bit of gunk that had developed along the inside of the flywheel
That spins along the outside of the stator... I used a rag with some wd-40
And used little circles to clean it. (Turned the rag black!) Put everything
back together, fired it up, and wham! 13.8v at idle, 14.4-8v with rpms.
What just happened? Maybe in the assembly/disassembly a connection
Was improved, or maybe the thin gunky film I cleaned off made all the
Difference... Whatever the case the bike is running and now I have an
Extra stator on the way and an extra rectifier. The battery is charging
And I am a happy camper.

Thanks for all the help!!!!!!! I hope this fixes my problem... Now I'm on
the hunt for the world's smallest voltmeter so I can stick it to my
Odometer and watch the voltage in the future. Dips below 12v then I
Know I have a problem......

RuZ


(Sorry, formatting is goofy because I'm on my blackberry)
 

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I'm kind of betting on the better connection hypothesis myself.
By disconnecting and reconnecting the stator connector, you may have rubbed off some oxidation on the contacts.

That's the main reason I remind everyone about dielectric grease.
It helps prevent this kind of stuff from happening.
I put that stuff on every connector I could get my hands on.
Including the sparkplug boots. It helps prevent the rubber on the boots from heat bonding to the plug porcelain.
I saw plenty of corroded and oxidized contacts on my old wiring harness connectors during replacement. No doubt from the rain or condensation in the winter.
 
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