I bought this quad for my son from a guy who said he could never keep a battery in it charged and had a friend of his replace the stator. He hadn't tried it since then though since his daughter lost interest.

I have the quad running now and the charging issue persists. The quad will run well off the battery. I have probed the battery both running and not and there is no change in voltage so I know the machine isn't charging. I assumed the issue to be a rectifier problem but did some research and probing anyway.

With the research I have done in this forum it appears that my issue is indeed still a stator problem but I want to double check with someone more familiar with these than I am before I go buying parts I don't need.

My stator has 5 wires: yellow, white, green, blue/white and black/red.

I believe that the yellow and white are the ac battery charging winding. I read that this winding should have a reistance of 1-2 ohms. Mine measures .6 ohms. I also read that this should produce 9.5v AC. Mine puts out 1.8v AC.

I also tested black/red to ground which comes in at spec of 85v AC and the blue/white to ground puts out .6v AC.

I believe that this means I have a possible short in the stator winding of the battery charging circuit and thus the low voltage output.

Disagree? Agree? Additional thoughts?

 

Do the tests over, but this time measure each wire to ground. I bet you'll find that you have more than sufficient AC voltage to charge the battery. Most 90cc charging systems use a single coil for the charging system with one end grounded. The other end end of the coil goes to the regulator, as well as a lower voltage tap off the battery charge coil. I suspect that you are measuring between the hot end of the winding and the slightly lower voltage tap, which will be a really low voltage compared to either of these wires to ground. Note that these type stators have two coils in them - one for charging the battery (through the voltage regulator) and one for making the moderately high voltage AC for running the CDI. These coils have nothing to do with each other - hence there is only a single coil to charge the battery.

Some quads in this engine size have a battery charge winding that has several coils (6 or 8) in in arranged in a starfish pattern. One of the arms in the "starfish" has the CDI power winding, the rest are all wired in series and are used to charge the battery (through the voltage regulator). On these stators the winding ends do not have one side grounded. In this case you would measure between the two wires. Perhaps this is what is causing confusion.

This is measuring the other coil used to power the CDI, and the trigger coil mounted outside the flywheel. They have nothing to do with battery charging issues. The readings look good BTW, but you could also tell this simply because the quad runs - therefor you are getting spark.

Disconnect the voltage regulator and measure the AC voltage on the yellow wire to ground, and also the white wire to ground at idle. What do you see? If we see sufficient voltage here then you most likely have a bad regulator, and not a bad stator.

Be careful where you buy a new regulator from. I've taken apart several regulators and traced out the internal circuitry. They all use the same connector, and look similar from the outside, yet they are not compatible at all. If possible make sure you deal with a vendor that knows it will work in your exact quad.

 

A lot of my research came from a post about a 150cc machine. Apparently the systems are quite different. Glad I asked.

Looks like you are right. While running the stator voltage to ground is 22vac (white) and 16vac (yellow).

While running w/ the vr disconnected I have 14vac (yellow) and 17vac (white).

Just for giggles I backprobed red at the vr with it plugged in and got 12.33 vdc which was battery voltage. No increase is present.

How do I make sure that the new VR will work correctly with my quad? I bought it used and really don't even know who made it.

 

I wish I had a good answer.

All of the 4 pin regulators that I bought were from eBay. All of them claimed to fit 50, 90, 110cc machines. One even claimed to fit these engines plus a 150cc GY6 engine (which of course I knew - and you now know - could not possibly be true). All of them were rock bottom cheap. After all, my intention was to machine off the aluminum fins and rip them apart. I didn't want to spend a lot of money.

I would stay away from ebay 4 pin regulators based on my experience. All of the regulators looked like they would work for a particular style stator, but that usually isn't the most common type. Weird left field designs get unloaded on the surplus markets by people who have no idea what they are selling. It looks the same so it must be compatible, right? [Wrong.] When you couple that with the fact that most buyers don't have a clue either the they can get away with it.

What you want is the most common style 110cc E22 engine voltage regulator, which is powered from a stator that has only two coils inside the flywheel [one for the CDI power and one for the battery charge circuitry].

This is one case where maybe cheap isn't the best way to go. If it were me I'd buy from a more well known vendor who's been around the block and has good reviews. Your chances will be better.