- Posts: 10868
- Thank you received: 1616
Troubleshooting Snerff 78 KZ1000
- loudhvx
- Topic Author
- Offline
- KZr Legend
I do have another question. When I put the meter across the battery posts with the engine running It was reading almost 17 volts. That seems too much. Could the regulator be bad? Thanks again.
1981 KZ550 D1 gpz.
Kz550 valve train warning.
Other links.
Please Log in or Create an account to join the conversation.
- loudhvx
- Topic Author
- Offline
- KZr Legend
- Posts: 10868
- Thank you received: 1616
What voltages do you get?
If the brown wire is at 17v, and the black wire is zero, then the regulator is bad.
If the black wire is anything above 1v, then the ground connection is bad somewhere, or the ground wires are not heavy enough.
If the brown wire is about 14v, and black wire is zero, then the regulator is probably good, and you are losing voltage in the ignition switch, fuse box, or wiring. The path in question is from the battery-positive to solenoid to fuse to ignition switch to brown wire on the reg. Each of those points should be at the same voltage as the battery (while running with the battery at 17v).
1981 KZ550 D1 gpz.
Kz550 valve train warning.
Other links.
Please Log in or Create an account to join the conversation.
- snerff
- Offline
- User
- Posts: 58
- Thank you received: 0
Please Log in or Create an account to join the conversation.
- loudhvx
- Topic Author
- Offline
- KZr Legend
- Posts: 10868
- Thank you received: 1616
Thanks again, I will try that tomorrow morning. Also Z1 sell a combo unit to replace existing setup. If things are bad mabey I could get that unit. It is supposedly easy to wire up.
Yes, I would definitely consider that new unit from Z1. The old reg and rec are near the end even if they work now. But still would be nice to know for sure what the existing problem is.
1981 KZ550 D1 gpz.
Kz550 valve train warning.
Other links.
Please Log in or Create an account to join the conversation.
- snerff
- Offline
- User
- Posts: 58
- Thank you received: 0
Please Log in or Create an account to join the conversation.
- loudhvx
- Topic Author
- Offline
- KZr Legend
- Posts: 10868
- Thank you received: 1616
Probably for the best. The new unit will simplify the wiring anyway. I can update the drawing when you get it. Just to make sure, you are using the stock charging system, correct? Alternator, that is.
1981 KZ550 D1 gpz.
Kz550 valve train warning.
Other links.
Please Log in or Create an account to join the conversation.
- MFolks
- Offline
- User
- Posts: 6650
- Thank you received: 540
1982 GPZ1100 B2
General Dynamics/Convair 1983-1993
GLCM BGM-109 Tomahawk, AGM-129A Advanced Cruise Missile (ACM)
Please Log in or Create an account to join the conversation.
- wiredgeorge
- Offline
- User
If the brown wire is about 14v, and black wire is zero, then the regulator is probably good, and you are losing voltage in the ignition switch, fuse box, or wiring. The path in question is from the battery-positive to solenoid to fuse to ignition switch to brown wire on the reg. Each of those points should be at the same voltage as the battery (while running with the battery at 17v).
Help me out here with a bit of clarification. I much appreciate when you make posts as they are informative. IF you have 14 VDC on the brown and zero on the black (ground), how could you have 17 VDC at the battery? Is this what you were saying in the part I quoted or did I misunderstand. Thanks in advance. wg
wiredgeorge Motorcycle Carburetors
Mico TX
www.wgcarbs.com
Too many bikes to list!
Please Log in or Create an account to join the conversation.
- snerff
- Offline
- User
- Posts: 58
- Thank you received: 0
Please Log in or Create an account to join the conversation.
- loudhvx
- Topic Author
- Offline
- KZr Legend
- Posts: 10868
- Thank you received: 1616
loudhvx - You stated:
If the brown wire is about 14v, and black wire is zero, then the regulator is probably good, and you are losing voltage in the ignition switch, fuse box, or wiring. The path in question is from the battery-positive to solenoid to fuse to ignition switch to brown wire on the reg. Each of those points should be at the same voltage as the battery (while running with the battery at 17v).
Help me out here with a bit of clarification. I much appreciate when you make posts as they are informative. IF you have 14 VDC on the brown and zero on the black (ground), how could you have 17 VDC at the battery? Is this what you were saying in the part I quoted or did I misunderstand. Thanks in advance. wg
This is a very common condition when the wiring is old on a stock bike.
Assuming the regulator, rectifier, wiring, and switches are good, this is what normally happens: The alternator puts out as much current as it can. The regulator shorts out as much current to ground as it takes to maintain 14v on it's sense line. The rectifier rectifies the remaining current into DC and that DC gets routed to the battery. The battery voltage gets routed through fuses, ignition switch, and several connectors to finally feed the battery voltage to the regulator's sense line. There is no significant current in the sense line. Notice how it forms a feedback loop. The regulator controls the voltage to the battery based on the voltage it senses on the sense line. If the alternator starts to put out more, the rectifier puts out more and the battery voltage goes up. This raises the voltage on the sense line which in turn causes the regulator to reduce the current to the rectifier (by shunting excess to ground). This will then lower the battery voltage back to 14v. It happens so quickly you may not even notice a fluctuation on a meter.
As I said, the sense line uses very little current, so the wiring of the sense line will cause very little voltage drop. If the sense line were switched directly to the battery without any other devices connected, it would work perfectly. However, the sense line is not exclusively connected to the battery. The sense line is connected to the main circuit coming from the battery. This circuit feeds lights, ignition, and other accessories. This large current draw causes voltage to drop along the path (in the fuse box, switches, etc.) if the wiring is old and switches/connections are dirty. So here's what happens: Let's say the battery for a moment is at 14v. The path, through which the sense line is connected, loses voltage due to the high current load. Lets say the fuse holder drops 1 volt and the switch drops 1 volt. Now the end of the sense line at the regulator is at 12v. The regulator is tricked into sensing battery voltage is 12v. The regulator must therefore increase voltage output by 2 volts to get the battery back to 14. Since the battery is really already at 14v, the extra 2 volts will force the battery to now be at 16v. Notice the regulator is basing it's operation on what voltage it senses from the sense line to ground. Since it is getting an artificially low sense voltage, it forces a much higher battery voltage.
The same thing can happen if the ground connection from battery to regulator is faulty. This is less common (but not uncommon). This will have the same effect, generally speaking.
This whole problem is the same as the low-voltage-to-the-coils problem and is caused by the same type of condition, but in slightly different areas. The coils issue emanates from a slightly later area in the path.
This problem is why it is important to base system voltage readings from the actual negative terminal of the battery and not some other arbitrary ground point, and regulator voltage readings should be done at the battery's positive post. Anywhere else may be misleading. If a problem is detected at the battery, then voltage readings should be done along the path to the regulator to isolate the problem area.
Notice in snerffs case, I told him to verify the voltage on the brown sense wire on the regulator. This was to make sure the sense line was not losing voltage. It wasn't, so therefore, in his case, the regulator was sensing 17v and maintaining 17v. That is a bad regulator.
Notice when the sense line is losing voltage, the regulator is sensing 14v and maintaining 14v. That is a good regulator, but the wiring is forcing a false reading to the regulator. This causes a high voltage reading at the battery. This problem often misleads people into buying new regulators when all they really have to do is clean some contacts and/or restore some wires.
So if a reg/rec combo has it's output wire tied directly to the battery, why use a seperate sense line? That seems redundant. Well, it's because the sense circuitry of the regulator may use a tiny bit of current if it is hooked up to the battery all the time. This may potentially drain the battery. That's why the sense line gets disconnected when the ignition is off. Some reg/rec combos, however, are designed to use so little current they don't need a seperate sense line and "sense" the voltage directly at the output wire (which goes directly to the battery usually via the start solenoid). I believe the 1-phase KZ650 reg/recs do this (circa 1978, 1979). But I think Kaw went back to a sense-line configuration on later models because of possible slow-drains on those 650 reg/recs. There may also be an issue with charging batteries that are still connected to the bike with the no-sense-line reg/recs. Since the sense circuit is connected all the time, a large charging voltage may damage the sense circuit on the reg.
1981 KZ550 D1 gpz.
Kz550 valve train warning.
Other links.
Please Log in or Create an account to join the conversation.
- inline79
- Offline
- User
On the KZ650 generator, the history goes something like this:
1977 - field coil style with mechanical regulator and rectifiers
1978 - single-phase stator with reg/rec combo (no sense line)
1981 - three-phase stator with reg/rec combo (w sense line on ignition circuit)
The three-phase system is clearly superior - I am in the middle of upgrading my KZ650C2 to KZ650-H1 stator, reg/rec, ignition systems.
I'm undecided about these sense lines though, and may run mine back to the battery positive. If you have some corrosion in the electrical system, the reg/rec may run at full output and self-destruct. A modern reg/rec should have minimal drain on the output, so if you are parking for a while just disconnect the battery negative.
Please Log in or Create an account to join the conversation.
- loudhvx
- Topic Author
- Offline
- KZr Legend
- Posts: 10868
- Thank you received: 1616
I'm undecided about these sense lines though, and may run mine back to the battery positive. If you have some corrosion in the electrical system, the reg/rec may run at full output and self-destruct. A modern reg/rec should have minimal drain on the output, so if you are parking for a while just disconnect the battery negative.
I wonder the same thing. Hopefully the new reg/recs without sense lines have no issue with slow draining the battery or damage from battery chargers. It shouldn't be too hard to protect against that.
1981 KZ550 D1 gpz.
Kz550 valve train warning.
Other links.
Please Log in or Create an account to join the conversation.