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Discussion Starter #1
I've put Honda CB125S engine in a Honda CR80 frame, for my daughter. Would like to have done away with the battery, but couldn't see a way of making it work. I have s simple charging system with a tree wire rectifier. Trouble is, the rectifier keeps over heating and the battery is being overcharged. Any ideas?
 

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Discussion Starter #3
From the 125. The 80 had CDI. Wish I could fit CDI!! The regulator is built into the rectifier.
 

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I'd put a meter on the regulator, output side. An old fashioned dial voltmeter is actually better for showing intermittent voltage irregularities, unless you get a very expensive digital meter that logs changes. The cheap digital meters don't update changes fast enough, and the voltage may appear to be steady when it really isn't.
 

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Discussion Starter #7
Just fitted a new regulator/rectifier I bought off eBay. Now I'm measure 30-40 volts across the battery. Can this be right?
 

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Nope, something is wrong there, it should be around 14. Don't run it that way or you will fry something ( or a few somethings) for sure.
Just fitted a new regulator/rectifier I bought off eBay. Now I'm measure 30-40 volts across the battery. Can this be right?
 

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Sounds like the regulator is junk, or you've got some wires mixed...30-40 volts is what you get from the dynamo, which is what the regulator is supposed to regulate down to 6. Is it reading the 30-40 with the bike running? The regulator is the easiest to fry part in an ignition system, one mistake, like hooking up the battery backwards, and it's toast.
 

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Here's the whole story. I have put CB 125 engine in a Honda CR80 rolling chassis for my daughter. The bike is great in many ways, but has been a bit unreliable due to the electrics. I was about to tear my hair out before I found a post about battery eliminators. I wondered if this could be my answer? Anyhow, back to the beginning. When I initially wired it up and got it going, I was measuring 20-30 volts across the battery. I have fried two dry state batteries and boiled dry one lead acid battery. I replaced the rectifier with a rectifier/regulator, which was fine for while, although it ran very hot. So hot in fact that you couldn't touch it, and the plastic protector melded and dripped off. Now it is not charging, so the battery goes flat. So I replaced the rectifier/regulator with what turns out to be just a rectifier off ebay. Now reading 20-30 volts across the battery again. I do wish people would described their stuff accurately!! So I am interested in converting the system to capacitor. The wiring system I have used is as shown above. Hope you can see it when I hit post. Any suggestions comments? Am I going down the right road here?
 

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So what you really need is a good 6 volt regulator. Shouldn't be too hard to find, but I'd avoid ebay. 30-40 volts across the battery is very bad, and means your regulator is doing nothing. I'll try to find a link to a reputable source for 6 volt regulators, unless someone beats me to it. I know Powerdynamo makes them for their 6 volt electronic ignition systems, and they also have the battery eliminator option. They have a warranty and reasonable instructions, translated fair enough from German. I put one in my MZ and have had zero problems.
 

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Discussion Starter #15
I guess in some ways that would be a simpler option. I will give it a go. Would I just cut the regulator into the red wire going to the battery?
 

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Yes, but be absolutely sure you have the polarity correct. If I recall correctly, there are 5 wires for the regulator, the two that go to the dynamo/generator are not polarity sensitive and are the same color, there should be a red and a ground and I believe a blue that goes to the coil. This is how mine was, anyway, the colors may vary. I'll double check my wiring diagram when I get home to be sure. In any case, your new regulator should come with a diagram of its own. Hooking up the battery in reverse will definitely destroy the regulator.
 

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Call these guys

Due to the fact that their website is a little difficult to navigate, call or E-mail them. I have bought twice from them and it sure is nice to be able to get plug and play parts instead of adapt to fit E-bay stuff. I was very impressed with what they sent for my CB550.

Depending on your model, you can get all in one units or separate regs and rects for your application.

http://www.regulatorrectifier.com/catalog/Honda-184.

Also,ask if they can help you out with the shipping. I did and sent me a 5$ off code to order the part.
 

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I have a few bikes from the 60's and 70's. I have converted them all to run without batteries. To make it work, you will need to use a modern regulator-rectifier in place of the basic rectifier (they can be had for $15). If your system is 12v, it's a piece of cake, as any reg-rec from a scooter or sportbike will do. If your system is 6v, you will have to convert to 12v, or get a specialty 6v regulator-rectifier (They're out there, but uncommon). In place of the battery, you will need to add a large capacitor. Based on my experiementation, it should be at least 20,000uf, or the bike will run rough. I reccomend 100,000uf or more.

The regulator-rectifier sends power out from the stator in pulses, and the capacitor must be there to absorb these pulses, and store the power to keep a steady flow going to the ignition coil. If the capacitor is too small, it will be hard to start, and run rough at low RPMs.

My 1968 CT90 has been converted for 12v, and runs without a battery, so it starts first kick every time, even after sitting for months. The new electrical system runs 50W worth the LED lights, and the coil draws another 50W or so.
 
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