I have a Buyang 70cc mini quad that is not charging the battery. It has a 2 coil stator (1 for spark, 1 for charging I assume). The resistance of the stator coil yellow wire to white wire is about 0.3 ohms. When the engine is running and the connector at the regulator is disconnected I measure 5 volts ac between yellow and white. I get no DC voltage coming out of the regulator when it is connected. Is my stator bad or my regulator? Also the lights do not work.

 

What is the AC voltage between the yellow wire to engine ground, and what is the AC voltage of the white wire to engine ground? Do this like you did the other measurement - regulator disconnected at idle.

 

What should I expect to see for voltages with these two tests you are describing? One end of that coil is grounded so it should be zero, and at the other I should get the same 5 volts AC?

 

It varies from quad to quad, and varies with engine speed, but I would expect 10 volts AC from one wire to ground and 15 volts AC from the other to ground.

When you say that one end of the coil is grounded you are correct, but that connection is neither the yellow or the white wires. The single charging coil has three connections coming out of it:

1) Ground
2) AC High
3) AC Low

You only measured the voltage from AC High to AC Low. Below is a wiring diagram of a typical charging system like yours. Note the stator (they call it an alternator) charging coil has ground and two AC output voltages goinf to the regulator:



I also have a buyang 70cc wiring diagram, but it doesn't show the 3 connections on the stator charge coil as clearly.

 

Ok, thanks that makes sense. I will check that later. Is the rectifier a simple bridge rectifier? What should I see for resistance on that?

 

I had the same question a while back. So I bought a few cheap 4 pin regulators on eBay and took them apart and traced out the connections. It was an eye opener to say the least. I found that the 4 pin regulators I had were compleletly different inside, and worse, completley incompatible with each other. The pinouts were not the same, nor was the internal topology. They looked exactly the same outside, used the same four pin connector, and shared *nothing* else in common.

This is a tough problem to deal with since a lot of chinese quads have no dealer support. You're forced to go with 3'rd party parts vendors who have no idea what the're selling. They buy a boat load of 4 pin things that all look the same outside - so they must be the same, right? And because really good mechanics are quite often baffled by even simple electronics there is no organized challenge to the flakey vendors, and on it goes.

I must admit, though, that my sampling of 4 pin regulators was rather biased. They all came from ebay and were being sold *dirt* cheap by vendors who were obviously clueless as to what they were selling. For example they claimed compatibility with both E22 and GY6 engines (completely impossible). They claimed that this fixes no "spark problems" (utterly ridiculous). But I bought them because they were cheap - and I was going to destroy them anyway by disassembling them.

So if you do measure voltages on the yellow and white wires to ground and you get something like expect then I think this is what is inside your quad regulator:



Obviously it is a lot more complicated then a simple bridge rectifier. In fact the bridge rectifier that is in there isn't even used to charge the battery. Instead it is part of an old shunt style AC voltage regulation system for running AC powered lights - that isn't used at all by many quads. Go figure... Its an archaic copy from decades old technology.

 

OK, I got the voltages expected when I test from ground to yellow and ground to white, also noticed that the lights work when I have the rectifier/regulator disconnected and when I reconnect it the lights go off. So I am quite confident I need a new regulator. Next question is where and how do I find the right one. I will try my local parts guy but I am a bit doubtful. Maybe I can find a website online that will ship to Canada.

Thanks alot for your help LynnEdwards!

 

You're welcome for the help.

As far as getting a regulator that works if it were me I would try getting a Giovanni regulator. The wiring diagram I posted before was for a Giovanni 110cc machine, and their wiring diagram looks like it is compatible with the measurements you have done.

I would *not* buy the cheapest regulator from eBay or any other source where they are selling surplus inventory from some obscure source.

You list your location as "Flon Flin manitobain". Is this the same as Flin Flon Manitoba? If so I've been there, but it was a long time ago. It is a place I will never forget, for sure . I was passing through the airport there on my way to an even smaller place called Jan's lake in Saskatchewan to fix some equipment on a helicopter. It was early spring and unseasonably warm in California. I checked all my winter gear in stowed luggage, which was all lost on the way to my first stop in Winnepeg. When I arrived in Flin Flon I had no coat, no gloves, no hat, no nothing. It was 40 degrees below zero. Even worse, I realized as the small commuter plane slid to a stop at the end of the runway, that I was going to have to run the 50 yard gauntlet to the terminal building out in the open. I really thought I was going to die .

I was a boy scout when I was a kid, and we were always taught to "be prepared". Obviously I didn't learn that lesson. But you can rest assured that Flin Flon taught me a lesson that will never be forgotten...

 

Yes that is the same as Flin Flon, Manitoba, (spelling error). I am always amazed at the amount of people that have a story about Flin Flon, very cool. I have found a place in Saskatoon that has the parts I needed. I was also looking for some different sprockets to slow this atv down abit for my kids.
Thanks again for your help.