'79 KZ650 B3 Still not charging properly

OK, quick recap. In more than 3 years, I've never gone over 400 miles without eating a battery, stator, regulator/rectifier, or some combination of the above.

So far, I'm 4 batteries, 4 regulator/rectifiers, and 2 rotors, and now 4 stators in.

There were also other serious electrical issues, which I believe are resolved. We ended up changing the entire wiring harness, and going over every inch of that with a fine-toothed comb, cleaning and replacing as necessary to ensure the voltage at the termination point of every wire was at or near it's voltage when coming out of the fuseblock.

So, it's all buttoned back up, and it's been driven about 130 miles. I've had one of these voltmeters for awhile

www.kuryakyn.com/index.cfm/go/Home.Produ...22/scID/133/IMID/872

and wanted to start hooking it up. Just for the hell of it, we held it on the battery terminals to see the LEDs light up. At idle, only the yellows lit up. At 4000 rpm, the first green would eventually light up after 30-40 seconds, but only the first one.

We put the voltmeter to it. At idle, it's putting out about 12.2-12.4 VDC. When held at 4000 rpm, it slowly rises to about 13.6 VDC, drops to 13.3 VDC, slowly rises back to 13.6 VDC, drops back to 13.3 VDC, and continues to go through that cycle as long as it is held at 4000 RPM.

Now, I'm thinking the dropping from 13.6 VDC down to 13.3 VDC over and over is the voltage regulator working. From the reading I've done in the factory service manual and the Clymer manual, though, I thought that wasn't supposed to happen till voltage was much higher; 15 VDC or more.

If that dropping and climbing back up is the regulator/rectifier, why would it happen at only 13.6 VDC?

Part II: That @#$%^&!!! KZ650 eats another stator

After losing two used stators, I sent one to Rick's Motorsport Electrics and had it rewound. Less than 400 miles later, it too was dead.

There's a bracket that holds the wires coming out of the stator out of the way of the rotor. It's held in place by two screws. When we took the side cover off, we found those screws loose, and the wires were all chewed up from rubbing against the rotor. We tried splicing the wires, but once we did, they wouldn't fit behind the bracket. We had a used stator and put it on the bike.

After we checked the charging voltages at the battery and didn't get the numbers we liked, we pulled the side cover and checked the stator output. Clymer calls for 75 VAC @ 4000 RPM. At 4000 RPM, the best we're getting is 68 VAC. At 5000 RPM, it jumps up to 80 VAC.

Clymer outlines a resistance test for a stator. It says there should be no more than 4 ohms resistance, this one has 8 ohms resistance.

The guy who is working on the bike said he didn't think 8 ohms vs. 4 ohms resistance was that big a deal. Is he right, or does that indicate this stator is bad?

Also, how does the low stator output relate to the 13.6 - 13.3 - 13.6 - 13.3 VDC cycling the regulator appears to be doing?

Also,

How come my sig is MIA?

Guessing a typo, but it's VAC from the alternator to the rectifier, and VDC from the rectifier throughout remainder of bike's electrical system.

For info about adding sig, click > Here

Good Fortune!

Patton wrote:

Guessing a typo, but it's VAC from the alternator to the rectifier, and VDC from the rectifier throughout remainder of bike's electrical system.

For info about adding sig, click > Here

Good Fortune!

VAC, VDC, ... whatever.

Here in Oklahoma, volts is volts.

Ha ha ha ... I wish it was a typo. It's more an indication of my understand of motorcycle 'lectric. I went back and fixed it.

And thanks for the link on the sig. That's the clearest, simplest tutorial I've ever seen. It only took me three tries to get it right.

What's odd is, I had a sig, and don't remember deleting it. Oh well.

Now, how about your thoughts on the stator and regulator/rectifier?

First, ACV is not DCV. I know youre kidding when you say volts is volts, but they aren't. Another thing, even DCV is not DCV.

What I mean by that is, just because you have a voltmeter that says you have 12.5 DCV or whatever, does not mean you have a steady 12.5 volts of pure DC. The voltmeter averages the instantaneous voltage over a period of time.

You will never know what the true voltage is without using a scope.

That Kuryakyn voltmeter puts 12.5v in the green. Well it shouldn't be, for several reasons. First, to break even on current, the voltage should be closer to 13v of pure DC. Anthing below that could potentially be discharging. Second, since it won't be getting pure DC, it can even be discharging when the battery voltage shows up in the low 13's. This is because if the meter says 13v, that's the average. It may actually be fluctuating between 13.5 and 12.5. When you just pull a charger off a good, fully charged battery, the voltage is closer to 13.5 or higher, closer to 14v for a few moments. If the voltage is only fluctuating between 12.5 and 13.5, it is likely spending more time discharging than it is charging. If it was a steady, pure 13.5 it would be fine, but it's not.

An ammeter actually has the same problem. It averages. So if an ammeter to the battery says 0 amps, that's the average. You may think this is fine, but it isn't. If it is getting 0 amps average, it could possibly be getting 1 amp out for half the time and 1 amp in for half the time. This battery will eventually be drained even though the ammeter says 0. This is because of internal losses. The battery actually loses more energy than the 1 amp it produces because of internal resistance. Then when it gets 1 amp, it only gets charged by a fraction of that 1 amp worth of energy, for the same reason...internal losses. So in the real world, the battery must see an average gain in current on an ammeter to actually just break even. The voltage at which it breaks even, for the same reason of fluctuating voltages, may actually be in the low to mid 13's as shown on a voltmeter.

Only a scope will show the actual fluctuations. But if your meter is showing only in the 13's, you definitely still have a problem. It would be nice to put a scope on it and see if the regulator is shunting or not. If it is shunting at such a low voltage, you need to find out why.

On the other thread I gave a link on what to look for on the scope for shunt events.

Also, on the stators and rotors, have you measured them to see what the clearance is? That is the OD on the stators versus the ID on the rotors.

The 650's had several different permanent-magnet alternators and I don't know if it's easy to tell them apart or not. If the clearance is too big due to a msmatch on parts, that could explain weak charging.

These voltage checks, have you tried them with the headlght unplugged?

OK, here's the thing. I don't have access to a scope, and wouldn't have any idea what to look for if I did. I looked at the link you provided in the other thread, but it was all way over my head. I don't know anyone with a scope, either. I think you'd have to agree we're getting into electrical engineer territory there, aren't we?

Now, the outside diameter of the stator / inside diameter of the rotor is something I can get done, and will do so ASAP. I've looked in Clymer, and don't see any specification for what that clearance should be, though. Do you know what the clearance I should be looking for?

The voltage checks were done with the headlight on. The issues of the dim headlight and the voltage dropping to 8V at the headlight have been resolved, however.

I can understand how checking the output of the regulator/rectifier at the battery could be affected by a bad battery or a draw like the headlight, but I don't see how the headlight could be affecting the output from the stator to the regulator/rectifier. I'm getting 68 VAC @ 4000 rpm when I should be getting 75 VAC @ 4000 rpm. Could the headlight be causing that?

Also, I still need an answer about the 8 ohms resistance on the used stator when Clymer says it should be no more than 4 ohms resistance. Is that 8 ohms resistance enough to cause it to output only 68 VAC when it should be outputting 75 VAC? The guy who is helping me picked the used stator up at a bike salvage yard, and if there's any chance of getting his (my) money back on the part, I need a definitive answer on that as quickly as possible. It's been a week since he bought it, and I have to believe the more time that passes, the lesser the chances of a refund.

And regarding the 13.6 VDC - 13.3 VDC - 13.6 VDC - 13.3 VDC "loop" the regulator/rectifier is going through, do you believe that is simply the regulator/rectifier shorting itself as it is supposed to at 15+ VDC, and if so, why do you think it might be doing so at such a low voltage?

OK, I measured the OD of the rewound stator that had the wires eaten up. It is 3 73/128

I went to this conversion tool:

www.convertunits.com/from/3+73/128+inches/to/mm

It converts 3 73/128" to 3.5703125", and converts that to 90.6859375mm

Is 90.69mm mm close enough? Since I don't know the specs for the clearances here, I don't know how precise it needs to be.

I called Ricks about the possibility of repairing the chewed up wires on the rewound stator, and the 4 ohms resistance spec and 8 ohms reading on the used stator, but can't get past the receptionist from hell. She said she'd "fill out a ticket" for me and someone would get back to me. The last time that happened, it was 4 days later before anyone called.

I also called a big auto electric repair place here. He said he'd have one of his guys take a look at it if I brought it by, which I will do in a few hours.

seanof30306 wrote:

OK, here's the thing. I don't have access to a scope, and wouldn't have any idea what to look for if I did. I looked at the link you provided in the other thread, but it was all way over my head. I don't know anyone with a scope, either. I think you'd have to agree we're getting into electrical engineer territory there, aren't we?

Yes. Many things can't be resolved with just a voltmeter, unfortunately. Hopefully this can, but it will take longer without the scope, and more testing.

seanof30306 wrote:

Now, the outside diameter of the stator / inside diameter of the rotor is something I can get done, and will do so ASAP. I've looked in Clymer, and don't see any specification for what that clearance should be, though. Do you know what the clearance I should be looking for?

Don't know the exact numbers, but with all of the rotors and stators you have, are they all the same? If not then there may be a mix-and-match problem. Unlikely, yes... but we have to start checking everything right?

seanof30306 wrote:

The voltage checks were done with the headlight on. The issues of the dim headlight and the voltage dropping to 8V at the headlight have been resolved, however.

I would mount a voltmeter like we talked about (at the battery), and watch it while you ride. I think that is definitely your next project, and will speed up troubleshooting. Is your headlight able to be switched off? If not, may want to do some miles with the light off and watch what the voltage at the battery does.

seanof30306 wrote:

I can understand how checking the output of the regulator/rectifier at the battery could be affected by a bad battery or a draw like the headlight, but I don't see how the headlight could be affecting the output from the stator to the regulator/rectifier. I'm getting 68 VAC @ 4000 rpm when I should be getting 75 VAC @ 4000 rpm. Could the headlight be causing that?

Headlight won't affect the stator winding voltage test because the windings are not connected to anything but the meter during this test. This test, however, doesn't load the stator and is thus not very meaningful. When I do a stator output test, I use a couple halogen headlights. Then I measure the voltage on the yellow wires while the wires are powering three 55 watt halogen bulbs (in parallel). If it can power three 55 watt bulbs up to 15v (about 15~18 amps), at 3000 to 4000 rpm then you have a decent alternator. Do you have any old car bulbs laying around?

seanof30306 wrote:

Also, I still need an answer about the 8 ohms resistance on the used stator when Clymer says it should be no more than 4 ohms resistance. Is that 8 ohms resistance enough to cause it to output only 68 VAC when it should be outputting 75 VAC? The guy who is helping me picked the used stator up at a bike salvage yard, and if there's any chance of getting his (my) money back on the part, I need a definitive answer on that as quickly as possible. It's been a week since he bought it, and I have to believe the more time that passes, the lesser the chances of a refund.

I've never been able to get money back from a salvage guy on electrical parts. To me 8 ohms sounds too high for sure. without load testing, I can't guess what it would do the open-circuit output on the stator... as I said, that test is not the most telling unless it was zero or some other super low value.

seanof30306 wrote:

And regarding the 13.6 VDC - 13.3 VDC - 13.6 VDC - 13.3 VDC "loop" the regulator/rectifier is going through, do you believe that is simply the regulator/rectifier shorting itself as it is supposed to at 15+ VDC, and if so, why do you think it might be doing so at such a low voltage?

How regular is the pattern? Is it clock-like, or totally random in timing? I really wish I could see the shunting cycle. That may tell a good story.

Just to verify, your reg/rec is stock and only has 4 wires, correct? (I'm trying to keep track of several bikes and problems all at once, so sorry if I forget details.)

seanof30306 wrote:

I called Ricks about the possibility of repairing the chewed up wires on the rewound stator, and the 4 ohms resistance spec and 8 ohms reading on the used stator, but can't get past the receptionist from hell. She said she'd "fill out a ticket" for me and someone would get back to me. The last time that happened, it was 4 days later before anyone called.

Ah yes, no end to red tape. Did they list the same stator for all 650's from 78 to early 80's?

seanof30306 wrote:

I also called a big auto electric repair place here. He said he'd have one of his guys take a look at it if I brought it by, which I will do in a few hours.

Sounds good.