Only charging at idle. Really

[Mister J]

Some quick background first. 2007 S4R bought new off the showroom floor. No real issues, other than the stator failed a few years ago. So that and the regulator were replaced, and all was well. Fast forward to this year. Stator died again. Battery, regulator, and stator replaced. Everything should be just great again, but it's not. At idle, it's producing 13.7 volts, but as soon as any throttle is applied, the voltage drops to 12.5. My mechanic is stumped. The guys from regulator/rectifier dot com are stumped. Am I really the first person ever to have this issue? Oh, if it wasn't strange enough, I swapped regulators with a guy to see if it helped, and his volts are good with either regulator. And my volts are kooky with either one. Any help would be much appreciated.

[Speeddog]

That pretty well rules out the regulator.

Check the voltage across the three yellow wires coming from the stator, A-B, B-C, A-C.

Should be 17-37 VAC at 2000 rpm and 68-88 VAC at 6000 rpm.

[Howie]

Assuming the regulator is properly grounded the only two possibilities I can think of is the wiring between the stator and regulator or too much clearance between the rotor and the stator .  Do keep us posted!

[Mister J]

I will take this to info to my guys. I watched them test everything individually, but the clearance might be a thing (aftermarket stator). As soon as I know anything, I will post some hopefully useful info

[Speeddog]

There are (at least) two different diameters of the 3-phase rotor/stator.

Sounds like you've got a small stator running inside a big rotor.

[ducpainter]

There are (at least) two different diameters of the 3-phase rotor/stator.

Sounds like you've got a small stator running inside a big rotor.

Wouldn't the rotor be the small item, since the stator doesn't turn.