Hi Guys,

Noticed the stater motor today didn't have as much "spunk" as usual, checked the battery voltage and it was sitting at 12.2v, on the ride home I was averaging 13.8v-14v. I did a check of the charging system and it looks like my regulator/rectifier is toast but I'm looking for a second opinion on the stator.

The service manual states to unhook the leads from the R/R that go to the stator and measure the voltage off the 3 black wires. I was reading around 70v at roughly 4,100rpm (its a lot harder to hold 4,100rpm than it sounds) and according to the service manual, that means the R/R is bad and needs to be replaced.

I then checked the resistance on the R/R and verified that it is indeed bad (readings from the black wires would fluctuate and between the blk/yw was way out spec as well, etc).

I checked the stator resistance, between the coils was good (0.4 to 0.5 ohms, within spec) however there's a bit of a question about between the coils and the ground. The SM states that "any reading other than infinity [open] the stator has a short" however, all 3 coils had readings WELL above 11 Mohms (mega-ohms) which while isn't an open circuit is a ridiculously high reading.

So, seeing how the SM has lead me astray before (find my posting about the starter problem if you're curious) I personally think the resistance reading is fine. I'm more concerned about the high voltage reading, the SM states that above 51v @ 4,100rpm means the R/R is bad, but it says nothing about the stator.

Since the leads I am taking a reading from are from the stator and the R/R is unhooked I'm at a loss as to how this reading can determine that the R/R is bad and not the stator (or as well). I'm assuming the SM is assuming (yup, see what I did there) that if the output voltage from the stator is high than the R/R has already been fried and needs replacing. The concern would be, if the high voltage cooked the R/R then ONLY replacing the R/R would result in the new one being damaged as well.

I'm guessing the consensus is "if in doubt, replace the stator", which I probably will end up doing, I'd like to know more about this particular test and if its simply something the service manual left out.

Actually, I re-read the service manual, apparently the reading is supposed to be at 4,000rpm (not 4,100) so I suspect the actual voltage is lower than 70V. It also says the reading should be "51V or more" and if "the output voltage shows a much higher than the table, the regulator/rectifier is damaged."

While Kawasaki gets a gold star for being vague, I'm pretty sure my stator is good.

Sounds like it. 70v@4k is not under 51v. .4 and .5 is not out of spec if .04 or less is. Maybe if I explain it this way in the generic... Harley uses a 32a stator. There are 2 wires coming out of the stator, 3 out of the kawi. The metal cores that the wire wraps around are those magnetic field passes at the core, where the wires are heavily wrapped around those posts.

If we breakdown the wiring, it is one continuous wire in, then wraps around a core, the wire is then going to wrap the next core and so on; until the other wire end is now the other end of that wire out of the lower engine case. Since we now established a single continuous wire, we want to see if a core has been cooked, heated, broken so as to stop the flow or cause a resistance at some heated area.

If we breakdown the assembly, we could say that half of the 360° spin is half, or 16v out of one wire, 16v out the other wire is AC traveling back and forth for an even number of 16v heading towards the vo/reg. The faster you move past a core, the more electricity is made.

If we check for voltage readouts, we'd have to look at this single wire as one continuous value. If a core is burnt, then the other wire is going to show it, as will the other wire showing this resistance happening in either direction. So fore every action of AC, there is an equal and opposite value out of those 2 wires [that make one long wire wrapped around those cores].

The ohm meter volt check:
DC 250v scale, I should see 51v or more between wires. I should see the same voltage if I ground the ohm meter to the engine, prong the 3 black wires; they should have the same equal numbers out... it's still one long wire, you holding 3-ends ala HD.

The ohm meter resistance check:
Set to the infinity scale. My 3 wires have to have equal resistance or one of my core windings off the one wire is burnt thru, melted the plastic coating that separates the wires laying on each other, sends the resistance down that wire. Any resistance shown is the copper wire has bled to ground. With the meter, the needle should not swing as if the meter prongs are not touching each other. Any slight resistance, the meter needle/digital number will show there is contact to ground.

The stator sweep:
If the 2-wire harley stator shows an output of 16v at half the 360° turn, 16v sweep at the other half, it still puts out a constant 16v up the wire to the vo/reg. The vo/reg is handcuffed to the DTT, so the trigger is filling the capacitors, the threshold has been met, the discharge to ground has been made. Lose a core, the sweep fluctuates, no longer is the current equal at the half-sweep.

The dash read:
If at idle, my volt readings should be between 14 and 15v. So if I have the headlights on, hit high beam, the voltage should rise. If I unplug the headlight, the volts should come down to 14v or so. My battery needs to be well charged so this vo/reg can show change.

The 3-system diagnosis:

Battery... I have to show 12.8-12.6v in the static or the battery is not well charged for the test. Over 12.8v, there is a vo/reg problem. Under 12.6v, there is a stator problem.

Vo/Reg... I have to show an overcharge past 15v, where this has the stator pushing volts past the vo/reg, finds the shortest path thru that unit, and overcharges the battery. There is no longer a diode in play, no longer a capacitor holding excess, no longer the DTT in action, the vo/reg acts as one wire path from stator to battery = Boiling out the battery acid, case expansion occurs, sulfur smell, etc.

Stator... I have to show a constant number/resistance thru each wire being equal; is one continuous wire wrapped around metal cores. Lose a core, you loose the half-loop (HD) or 1/3rd-loop of this 3-wire stator. Therefore, I am equal out of the wire is volts, equal in infinity is each wire not melted to the next wind it lays over, or I have a resistance problem, my voltage goes to ground, not up the wire(s).

See if this makes sense.

* Last updated by: Hub on 10/21/2015 @ 7:56 AM *

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Hey Hub, Thanks for the feedback, more or less makes sense. Good point about the stator being a continuous long loop, that's supported by the fact that the resistance reading between each lead is the same and is relatively low (4ohms)as that's just the resistance of a rather long wire.

While I never tested the theory (might do that when my new R/R arrives) but there should be no voltage reading from the generator to the ground since we're talking about AC voltage and the generator should be isolated from the ground (unless as you said, the insulation on the wires is damaged).

Regarding the R/R (regulator/rectifier), you were explaining that if one of the parts of the stator is fried than the issue will be insufficient current to drive the R/R so in theory the system should still function, just at a reduced capacity.

I haven't seen any sign of the system overcharging the battery but I wouldn't be surprised if its useful life has been cut short.

Out of curiosity, does anyone know what the output capacity if the charging system is and what the motorcycle's average power requirement is (low beams, marker lights, vehicle running)? I'm assuming the system is designed to at the very least power the bike and its factory accessories (all lights & engine).

the issue will be insufficient current to drive the R/R so in theory the system should still function, just at a reduced capacity.

Correct. Still pushes current up the wire, but the resistance is the faster way to ground, the excess bleeds up the wire and shows 12-13v, not 14+.

I haven't seen any sign of the system overcharging the battery but I wouldn't be surprised if its useful life has been cut short.

Who, the vo/reg's life? Runs cooler, waits longer to trigger = Less sparks off the magnetic flipflopping in the chips.

Out of curiosity, does anyone know what the output capacity

Rated output is 35 A/14 V @5,000 rpm.
Rated battery is 12 V 14 Ah
Hi beam is 12v 55w + 65w
Lo beam is 12v 55w
Taillight is 12v 0.5/4.9 LED
Three-phase AC

I'm assuming the system is designed to at the very least power the bike and its factory accessories

Yes. They use formulas that you can math the system out as to proper power output, no strain on the batt/stat/vo-reg. It's a balanced system.

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I was referring to the useful life of the battery being cut short. And my question about the alternator output and the power requirements is to figure out how much overhead there is available.

Good question. A Yuasa tech sorta schooled me on initial charging out of the box. If they are competing with other brands for longevity, his was so basic, bmw's book charge is more elaborate... go figure.

The battery went down in charge, yes? So the thing to do is charge it while waiting for parts. Letting it sit longer is just more hours reviving it? How long before that liquid turns solid on the fibers so no passing of the chemical reaction. That solution needs to be fluid thru the process. You have the (-) and (+) separated in solution. They need to pass up and out the battery posts to DC something. That means the plates are going to be coated with the crystal forming on the plate material, you want to stop this or break them down back in solution.

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