How many different stators for the KZ650?

So my stator is bad, not providing any juice back into the battery. I know there are 2 phase and 3 phase stators, mine is a 79, 2 phase. So i bought a 1980 stator off ebay before checking here, it has 3 yellow wires coming off said stator, no go. I have a polished cover with a stator and rotor combined, 3 wires coming off the stator and a green wire to boot. I need a 2 yellow wire stator. the seller of the one with 3 wires agreed to cancel the transaction, so i found a 1978 SR stator and it is on its way from portland. So what is the timeline for stators. I am assuming the 1980 stator was the same as the GPz ones, and the one i have here with the polished cover is an early stator.

1977 kz650's have a 3 wire exciterd magnet stator, it is a good system if you have very low power need but it is a pretty weak charging system.

1978-1980 kz650's have a 2 wire perm. mag. stator, it is better than the 1977 system by leaps and bounds. It uses all different parts from the 1977 system, the stator, cover, rec, reg, and the rotor are all different.

1981-1984 kz650's have a 3 wire perm. mag stator, it is the best of lot also this is the one that electro sports and other companys offer as an aftermarket and over wound. This uses a different rec, reg, and stator from the 1978-1980 models.

There is more information that other members posted in my stator swap thread.

In terms of efficiency and versatility, the 77 system is the best, in my opinion. It uses a variable magnetic field to control the amount of output. That way they can design the alternator to be more powerful than is needed which means more accesories can be used. In fact, when the system is in perfect working order, it can give 14 volts even at idle. Some of the KZ400's use the same system. And this is with no brushes or slip rings.

The permanent magnet alternators have to be designed to match the loads on the bike because they put out full power all the time. This means the regulator has to control the voltage by shorting out the excess current. This wastes a lot of power and stresses the regulator at higher RPMs. because of this, they can't make it too powerful or it would burn out the regulator. This means it can't handle a lot of extra load for extra lights etc.

However, because of it's complexity and crude regulator/rectifier design, the 77 system is problematic. The permanent magnet ones are simpler, and if you get the higher rated aftermarket reg/recs, you can use heavier duty aftermarket stators to provide extra power.

Here's the info I have for 650 alternators:
As of 2005 from buykawasaki.com (their parts fiche program has changed a few times since then.)
KZ650 Alternators:

1977 B1 standard...3phase excited field
1977 C1 custom.....3phase excited field
1978 B2 standard...1phase permanent mag
1978 C2 custom.....1phase permanent mag
1978 D1 sr...............1phase permanent mag
1979 B3 standard...1phase permanent mag
1979 C3 custom.....1phase permanent mag
1979 D2 sr...............1phase permanent mag
1980 E1 LTD............1phase permanent mag
1980 F1 custom......1phase permanent mag
1981 H1 csr.............3phase permanent mag
1982 H2 csr.............3phase permanent mag
1983 H3 csr.............3phase permanent mag up to KZ650DE052650
1983 H3 csr.............New type 3phase permanent mag starting at KZ650DE052651

The excited field does not use brushes or slip rings. The field coil is affixed to the alt. cover. The rotor is a device which rotates through the field to bring alternating poles to the stator.
The 1phase permanent magnet flywheel is part # 21050-1003 for all years.
The 1phase stator is part # 21003-1005 for all years.

BuyKawasaki.com has errors regarding the regulators and rectifiers. They show the separate rectifier is also used on the 78, but it is not. It should be the reg/rec combo which is also labeled as just a regulator.

also, as a last note, if the stator for a 3-phase permanent magnet alternator fits physically into the cover and rotor for the 1-phase permanent magnet system (and I think it may), you can use the 3-phase stator as long as you get a 3-phase reg/rec combo.

Loud, is there any way to modify the 1977 system for higher output and a rec/reg that will handle it?

I am trying to power my o2 sensor reliable and the 1977 system is not cutting it. I get 14vt at idle so I always thought the problem was not enough amps being pushed through the system.

If it is a better solution I will stick with the 1977, but somehow I need to get more amps to power my innovate sensor.

loudhvx wrote:

...BuyKawasaki.com has errors regarding the regulators and rectifiers. They show the separate rectifier is also used on the 78, but it is not. It should be the reg/rec combo which is also labeled as just a regulator.

They also have errors regarding the stators, they show the same stator used on all models 77-80, which we know it's not.

loudhvx wrote:

...also, as a last note, if the stator for a 3-phase permanent magnet alternator fits physically into the cover and rotor for the 1-phase permanent magnet system (and I think it may), you can use the 3-phase stator as long as you get a 3-phase reg/rec combo.

The 3-phase stator will fit the 1-phase cover, that's the setup I'm running on the 79 engine I have in my 77: 3-phase hi-output Electrex stator in a 79 D cover (originally 1-phase) using the original 79 D rotor and a Tourmax 3-phase reg/rec.

Are you sure it's a current issue?

After warmup, the Innovate LC-1 and gauge don't use much.
Initially, it uses 2A at 13v when first turned on. Then .7A at 13.2v steady in free air. (But it doesn't necessarily need 13v, that's where I took the bench reading.)

Incidently:
With no sensor connected, .06A.
The G2 gauge uses .05A to .06A including lights.

I know that mine works down to about 11v, but below that it gets erratic. You can prgram where the needle goes to show you when the system is inop, warmup etc. (a very, very cool feature).

It may not be a current issue, but a voltage fluctuation issue, as that is a symptom of the mechanical regulator.

As I said, the 77 system is good if it's working perfectly, but it's such a complex system, after 30 years, it's likely not perfect.

When I replaced the regulator on my friends kz400, though, it started working great. He gets near 14v at idle and it just stays like that at all RPMs. But I had to make the regulator from scratch since I couldn't find one available at the time.

However, now there is a good one available at Oregonmotorcycleparts.com. He makes one specifically for the 77 kz650. I'd try him out before converting everything to a later style. But you also have to make sure all wires and connections are good, obviously.

Thanks for the confimation OnkelB, I'd hoped you'd chime in.

loudhvx wrote:

Are you sure it's a current issue?

After warmup, the Innovate LC-1 and gauge don't use much.
Initially, it uses 2A at 13v when first turned on. Then .7A at 13.2v steady in free air. (But it doesn't necessarily need 13v, that's where I took the bench reading.)

Incidently:
With no sensor connected, .06A.
The G2 gauge uses .05A to .06A including lights.

I know that mine works down to about 11v, but below that it gets erratic. You can prgram where the needle goes to show you when the system is inop, warmup etc. (a very, very cool feature).

It may not be a current issue, but a voltage fluctuation issue, as that is a symptom of the mechanical regulator.

As I said, the 77 system is good if it's working perfectly, but it's such a complex system, after 30 years, it's likely not perfect.

When I replaced the regulator on my friends kz400, though, it started working great. He gets near 14v at idle and it just stays like that at all RPMs. But I had to make the regulator from scratch since I couldn't find one available at the time.

However, now there is a good one available at Oregonmotorcycleparts.com. He makes one specifically for the 77 kz650. I'd try him out before converting everything to a later style. But you also have to make sure all wires and connections are good, obviously.

Bummer, I just ordered a rec,reg from him for the 3 wire system.

With my inovate sensor it will warm up and give me a reading then go nuts. I swapped it for a known good unit and had the same symptoms. My mechanic buddy removed the power from my bike and used a fully charged car battery to run the sensor and it worked mint. His conclusion was not enough amps to keep the o2 sensor up to temp.

So you think I should keep the 3 phase system that is on the bike? It already has a Oregon motorcycles rectifier on it. You think it I get the regulator as well I will finally get some usable data from the o2 sensor?

Does the 1977 system put out as many amps as the 1980 system? How would it compare to an electrosports stator?

hardr0ck68 wrote:

loudhvx wrote:

Are you sure it's a current issue?

After warmup, the Innovate LC-1 and gauge don't use much.
Initially, it uses 2A at 13v when first turned on. Then .7A at 13.2v steady in free air. (But it doesn't necessarily need 13v, that's where I took the bench reading.)

Incidently:
With no sensor connected, .06A.
The G2 gauge uses .05A to .06A including lights.

I know that mine works down to about 11v, but below that it gets erratic. You can prgram where the needle goes to show you when the system is inop, warmup etc. (a very, very cool feature).

It may not be a current issue, but a voltage fluctuation issue, as that is a symptom of the mechanical regulator.

As I said, the 77 system is good if it's working perfectly, but it's such a complex system, after 30 years, it's likely not perfect.

When I replaced the regulator on my friends kz400, though, it started working great. He gets near 14v at idle and it just stays like that at all RPMs. But I had to make the regulator from scratch since I couldn't find one available at the time.

However, now there is a good one available at Oregonmotorcycleparts.com. He makes one specifically for the 77 kz650. I'd try him out before converting everything to a later style. But you also have to make sure all wires and connections are good, obviously.

Bummer, I just ordered a rec,reg from him for the 3 wire system.

With my inovate sensor it will warm up and give me a reading then go nuts. I swapped it for a known good unit and had the same symptoms. My mechanic buddy removed the power from my bike and used a fully charged car battery to run the sensor and it worked mint. His conclusion was not enough amps to keep the o2 sensor up to temp.

So you think I should keep the 3 phase system that is on the bike? It already has a Oregon motorcycles rectifier on it. You think it I get the regulator as well I will finally get some usable data from the o2 sensor?

Does the 1977 system put out as many amps as the 1980 system? How would it compare to an electrosports stator?

Well, it's really hard to suggest what to do since I haven't really investigated your charging system. If it was me, I'd put a scope on it to see how much fluctutation there is. A voltmeter only shows the average voltage, but the instantaneous voltage can fluctuate a lot. If the voltage fluctuates too much due to the regulator contacts being flakey, the O-2 sensor's microcontroller may just shut down.

Another question, are you running resistor wire or resistor plugs or caps? If non at all, then that's another thing that can mess up sensitive electronics.

Are you using a Dyna S or Dyna III ignition? That uses a lot of power, which may explain low voltage if that's what the problem is.

Have you tried to run it all with the headlight unplugged? I'd try that at least once. On my bike, I have no battery, so Idle voltage is low, plus I'm also two 55watt halogens. The o-2 would shut off at idle, but turn back on when I revved the bike. After I unplugged one halogen it worked fine. (Since I don't have a battery, I don't care how low the voltage goes at idle, as long as it still runs, which is why I run two halogens, but that's only if I don't have the o-2 on the bike.)

Also, have you checked the voltage on the battery while the o-2 was going crazy?

I really haven't tested any aftermarket stators so I can't say how they compare to stock units. In my experience, the 77's put out more amps at idle (seen in the form of higher average battery voltage at idle), on the few I've tested, but the voltage jumps around because of the mechanical regulator. I'm not sure Ive seen a 77 with a new regulator, but the 76 KZ400 is essentially the same system and the one I built the regulator for puts out higher voltage at idle than my 550's with the 3-phase, permanent magnets.

If the original 77 system looks to be in bad shape, then I guess I'd say replace it as you had planned. But without testing, it's hard to say. Maybe it just comes down to what you think is easier for you to do. Stators, rotors etc can be had, used, for similar cost to the oregon regulator. Without some more data, it's sort of a toss up. If money is no object, get all new stuff. If money is tight, but you have a lot of time, I'd tinker with learning what is actually wrong. Nothing wrong with either method... just depends what you have more of, time or money.

Thanks for all the replies. I have a 1978 permanent magnet alternator on the way. if anyone is interested, i am listing the 1977 model excited field alternator on eBay with polished cover this evening. Just needed to verify what i have to work with.

Shoot Loud; now you have me sitting on a fence post. I have what I think is a good 1977 system that just doesn't cut the mustard. I also have a few spare stators for this system

I could upgrade the regulator for $120... and hope. If I upgrade the magnet and still don't get the voltage/ amp's I need (assuming that is the current (no pun intended!) problem) is there a way to boost output of the excited field system?

On the other hand I have two, three wire permanent mag stators that test good and a rec,reg on the way for them. I have not yet sprung for the over-wound stator.


Now I need to check on the resistor wires/caps (they were dyne wires and caps that I bought with the 3 ohm coils).




Help me decide! I intend to start building a fuel injection set up over the next few years and I know Dave Sloan gets by with an over wound permanent magnet system but I think he gets by just barely...

There are a few experiments you can do to eliminate the regulator as the problem. The regulator takes input power on the brown wire, uses it to determine battery voltage, then outputs power to the field coil on the green wire.

First experiment. Run a wire directly from the battery positive to the brown connection on the regulator. Then run a ground wire directly from the black connection on the regulator to the battery negative. This will ensure the regulator is detecting actual battery voltage. Then measure the voltage on the battery while revving etc. If the voltage is above 13v then the charging system is putting out enough to run the o-2 sensor.

If it does not get to 13v, try it with the headlight disconnected too.

Put everything back to normal.

If the charging system was providing 13v and the o-2 sensor was still going crazy, do the next experiment:
This nxt test is dangerous (to the bike) so very close monitoring must be done.
Pull the green wire off the regulator. Temporarily connect a jumper from the battery positive to that green wire. This will force the alternator to provide full output. Make sure you have a volt meter connected to the battery. Monitor the battery voltage very very closely while starting the bike. Do not rev the bike without monitoring the volt meter. Do not let the voltage go above 16v. If it won't go lower, shut the bike off.

Put everything back to normal.

Do these tests first, then I'll describe some others depending on how these turn out.

So all you need for the permanent magnet setup is the rotor and cover? Just curious.

Also, are you running a Dyna S?

Are you running resistor plugs, wires, or caps?

I don't want to get into a debate about the relay-coil mod, but if you have that, and it ran better, then there is a voltage loss somewhere. This can lead to over-voltage problems AND under-voltage problems in different areas of the bike depending on where the voltage loss is at. There is a chance that this is the real problem. But it will take some testing. We can go through those tests after you do the first two.