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Discussion Starter · #1 ·
I suspect my '71 may be overcharging (battery juice is coming out of the discharge tube), it reads 15.5v at around 4000 rpm. Is this too much? Would this indicate that regulator has gone bad? If so should I just look for a used one, or is there a more modern replacement available?

Thanks,
Greg
 

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Yeah that seems a little excessive.
Try another regulator - just about any regulator from any of these old Hondas will work, as long as it has the same connector and general form .........

There are modern replacements - some replace the regulator and rectifier with a single unit, and apparently work well -- try a Search here, I know this was a topic recently.
 

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Are you using a smaller battery than the stock one?

I used a smaller battery and the same thing happened.

It has to do with the total Amp hours the battery has.
 

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Discussion Starter · #4 ·
Dirtbag said:
Are you using a smaller battery than the stock one?

I used a smaller battery and the same thing happened.

It has to do with the total Amp hours the battery has.
Nah, I'm using a stock battery - about a year old and kept on a tender.
 

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I'd bet on a bad regulator, or disconnected, corroded, or poorly grounded wire on the regulator (green wire)... it can't shunt the excess to ground if it can't find a ground.... This particular problem is often associated with a powdercoated frame....
 

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Discussion Starter · #6 ·
66Sprint said:
I'd bet on a bad regulator, or disconnected, corroded, or poorly grounded wire on the regulator (green wire)... it can't shunt the excess to ground if it can't find a ground.... This particular problem is often associated with a powdercoated frame....
Well I did have my frame powedercoated, but I think I did a good job of cleaning the grounds. I tested the green wire on the regulator and it does ground both with the ignition on and off.

Does anyone know if a source for a good replacement regulator?

Thanks,
Greg
 

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Hi Gpdesign
You have checked the ground. Now check the black wire. With the bike running and the headlight turned on check the voltage difference between the black wire at the regulator and the positive terminal of the battery. Also check that the third wire from the regulator is connected correctly.
TomC in Ohio
 

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Discussion Starter · #8 ·
Well thanks for all of the good advice. As it turns out the culprit was my digital multimeter! I noticed while doing more testing that the voltage reading would continue to go up as the bike just sat at idle - strange I thought. So I rounded up a couple of other multimeters and their readings were consistent and correlated with each other. Using the new meters my voltage now reads fine and more in line with what a vintage bike should be putting out ~ 13v. Now I'm just bummed that my expensive multimeter has gone tits up! :evil:

btw, if anyone needs a solid state modern regulator/rectifier unit I found one that will work, its the VRRPM2-HCB at:
http://www.oregonmotorcycleparts.com/VRRPM.html
Luckily I don't need one - yet.
 

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SO WHY IS YOUR BATTERY DRIPPING FLUID?...........
 

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Discussion Starter · #10 ·
66Sprint said:
SO WHY IS YOUR BATTERY DRIPPING FLUID?...........
I need to figure that out. It could be the battery was overfilled or something. I've put on a catch bottle so I can monitor what is coming out of the overflow tube. On a quick half hour ride last night there was nothing so far.
 

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Hi Gpdesign
Check your rectifier. One or more of the diodes maybe conducting in both directions.
TomC in Ohio
 
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