Rode 40 miles then it quit...

Alright so your bike has a sense wire (brown wire). That brown wire gets battery voltage on it when the bike is turned on. The regulator uses this wire to determine the battery voltage in order to regulate the output voltage to the battery.


If the bike was overcharging, we would be concerned with the brown sense line, but since you are getting little to no charging, we need to determine if it's the alternator or the regulator/rectifier. The AC voltage test on the two yellow wires is the first step, as F64 is suggesting.

unplugged at idle 19-20 v and at 4000 rpm 71.5
plugged at idle 14.9v and at 4000 rpm 17.3

stator end of plug, unplugged and not running 1.0 resistance, but interestingly all three wires gave a varying flash number then to 1.0 each time. Number flashed was different each time and for all three wires(2 yellow and 1 black)

could not get a reading for reg unplugged. might not have set meter correctly.

I also checked the spark jump gap for all for leads. all flashed at the 1 mark but only two would flash at the 1.1 mark. None were what I would call bright and strong but all looked the same in intensity and color. I assume that is somewhat normal aside from gap distance. could be an overheating coil causing the quit after a few minutes of running. though could not get it to quit in garage as I was testing. riding is different tho

tried to post two pics of reg but for some reason they would not post like the carb ones had.again probably user error

checked all connections for corrosion and snugness. fixed one, did not really make a difference at the meter

F64 wrote: Check for AC Voltage on the 2 yellow wires at idle and at 4000rpm.
Backprobe the connector and make sure the two probes don't touch each other.
Tell us what the voltage is.

Stator looks good.
Let's check the wiring going to the regulator.

Meter on DC Voltage
Engine on
Black probe on negative battery post(the metal part of the battery not the terminal on the battery cable)
Red probe on positive battery post
Note voltage

Move red probe to the black wire at the regulator connector.
Note voltage(the voltage here will be very close to zero. Write down the result)

Red probe to brown wire at regulator connector
Note voltage

Red probe to red/white wire at regulator connector
Note voltage

Do not disconnect the regulator connectors when you do these readings. The circuits must stay complete.
Probe on the regulator side of the connector. This allows you to check the connections at the connector as well as the wiring to the regulator.

Apologies for delay on these results.. was not able to test until today..
Bike running at idle...
Voltage at battery posts... 12.3
Voltage at black wire.... -.15 to -.20
Voltage at brown wire.... 10.65
Voltage a tred/white wire.... 12.25

F64 wrote: Stator looks good.
Let's check the wiring going to the regulator.

Meter on DC Voltage
Engine on
Black probe on negative battery post(the metal part of the battery not the terminal on the battery cable)
Red probe on positive battery post
Note voltage

Move red probe to the black wire at the regulator connector.
Note voltage(the voltage here will be very close to zero. Write down the result)

Red probe to brown wire at regulator connector
Note voltage

Red probe to red/white wire at regulator connector
Note voltage

Do not disconnect the regulator connectors when you do these readings. The circuits must stay complete.
Probe on the regulator side of the connector. This allows you to check the connections at the connector as well as the wiring to the regulator.

No worries on the delay.
Life has a way of doing that.
Thanks for the readings.

The voltage on the brown wire concerns me.
It should be the same as the battery voltage(12.3).
I'm going to have you trace that brown to figure out where the fault is.
That lower voltage on the brown wire will cause overcharging of your battery.
Which in turn will destroy your battery.

As far as the charging system, it appears your regulator/rectifier is faulty.
You have options as far as upgrading or stock replacement.
Other people on this board would be much better than me on recommendations.

So that brown wire.
I don't have the schematic for your bike but I can get you close.
Do this while the bike is running.
You will take voltage measurements by moving the red probe along the brown wire electrically back to the battery.
You will find 10.65v along the way...as soon as you find full battery voltage(12.3 was what it was before)...stop..
The fault will be between the last 10.65v and 12.3. It could be a bad connection, pinched wire, corroded wire. Fix that segment of wire then your charging system should work better---after you get a new regulator/rectifier.
I'll include a schematic that should be close to your bike.
Anyone that has the proper schematic please post if possible.

Also a note, if your battery ever dies and a car jump starts you make sure the car is off or the car alternator output will damage your regulator.

Meter on DC V
leave all connectors connected

black probe on negative battery post
red probe on positive battery post
Note voltage

Red probe to the brown wire connection you checked earlier
note voltage

Red probe to brown wire in connector within the green circle
note voltage

The brown wire appears deep red on my schematic. The green line shows the path of your readings.

photo: kz440 service manual

Kinda figured reg was shot after those readings. Anyone have a good suggestion for a replacement for it?
F64 do you have any thoughts on the results from the coil tests I did and posted? I am unsure what the gap the spark jumps on the tester should be. Healthy or unhealthy. Beginn8ng to wonder if i don't need coils as well

I wouldn't worry about the coils yet.
Your coils depend on good voltage. Once we get your voltage up and steady, we'll look at ignition.

Fair enough. I will make time tomorrow to trace that wire. Thank you very much for your help

The brown wire gets power form the ignition switch which gets it from the main fuse. Typically the main fuse is the biggest culprit for voltage loss. Then the ignition switch is usually the second biggest. The coils get power from the kill switch which is also a cause of voltage drops.

After those places, any connector is usually a possible voltage loss location. If you can get the brown wire voltage to be within about 1/2 a volt of the battery voltage, you are doing pretty good.

This is not a factory diagram but is probably ok in a pinch.

Ok, interesting results. Seems like all the wires are pretty close to the same results. I went over all the connections I could find after testing the brown one. PO has the wire harness pretty electrical taped up tho, so i am sure i missed some. In the process I turned ignition on and one of the spark plugs fired! Don't know which one and it doesn't do it time i turn key on. It did do it twice tho.
After opening, using a dab of corrosionX on each connector and reconnecting the voltage measured 11.45 at the brown wire at the regulator. Seems like i have some wire harness issues somewhere.

Yeah, wiring can be crazy like that. It doesn't take much to cause you a bit of grief.

Concerning your reg/rec replacement. Many people will upgrade to a newer Shindegen reg/rec. As well as upgrading the stator to a 3 phase.
It really depends on how far you want to go.
Do a forum search here for Shindengen.
You may also just want to replace your unit with the stock unit. You have options.

so after much hunting I think i finally found a replacement reg for my kaw. It appears to be an electrosport 3 phase(has no brown wire) so it would appear i have more mods to make. Not sure how tho and thus my new question. How do I go from a 1-phase to a three phase so I can use this electrosport reg/rec.