Hold my beer, I got this

So the previous owner decided to jump start this bike (1979 kz650) with his car,
A few years ago when I got the bike I had removed the harness and cut all the loom off to see what was damaged, not too bad but not great.
I am looking to run a simple wiring harness including:
-Battery
-Original key switch (with original key)
-Tach
-Original right side controls
-Headlight/taillight (front leaver has a. switch but I'm using woodcraft reassess so I'll have to make a new tap for the pedal. switch)

If it's any help..
Vin: 1KZ650B525195
Thank in advance for anyone that can help
I will post some pictures of the components I have so you can see wire colors and things like that

KZR topic by loudhvx. bare bones for mattylight --- pg 14. 650-D2 -->> see reply #511882
There are a few more 650 diagrams below the 650D.

Note: a bunch of the wiring diagrams are no longer available on pg 1-10. I guess because of the recent KZR upgrade. ???
But from page 11-on, those are still there.

Maybe this is useful;
www.bikeexif.com/motorcycle-wiring

For the record, jumping a bike from a car shouldn't cause any damage. I would recommend not starting the car (the battery will be enough by itself), but even if it were running the risk is relatively low. It's really no different to putting a modern high-output battery into your bike. Jumping any vehicle has its risks.

Jump starting a bike from a running car or battery charger is a bad idea, and it really can damage the bike's electrical system. Keep in mind that not all KZ charging systems are the same, and a car's alternator can pump out much more amperage than that of the bike.

Also, see:

www.kzrider.com/forum/4-electrical/599820-charging-prob#692159

Ed

650ed wrote: Jump starting a bike from a running car or battery charger is a bad idea, and it really can damage the bike's electrical system. Keep in mind that not all KZ charging systems are the same, and a car's alternator can pump out much more amperage than that of the bike.

Also, see:

www.kzrider.com/forum/4-electrical/599820-charging-prob#692159

Ed

Yes, I commented in that link over a year ago

A car alternator can provide a lot more than a car or a bike, but no where near as much as a battery. My bike's battery can provide 220CCA, but it won't fry anything just from general use. The alternator in the car really doesn't add that much. In fact, most modern car alternators will output much less voltage than our old KZ alternators (newer alternators are usually about 14V, the KZ alternators are about 14.5V or even higher).

I agree that starting a bike from a running car is a bad idea, but only because the risk is slightly elevated and there's no reason to do so. The only real issue is pointed out by loudhvx in the thread you linked - that the regulator will be shunting the excess voltage. However, if your car is running at 14V and your bike at 14.5V, the car isn't going to be causing any problem.

Irish Yobbo wrote: A car alternator can provide a lot more than a car or a bike, but no where near as much as a battery. My bike's battery can provide 220CCA, but it won't fry anything just from general use. The alternator in the car really doesn't add that much. In fact, most modern car alternators will output much less voltage than our old KZ alternators (newer alternators are usually about 14V, the KZ alternators are about 14.5V or even higher).

I agree that starting a bike from a running car is a bad idea, but only because the risk is slightly elevated and there's no reason to do so. The only real issue is pointed out by loudhvx in the thread you linked - that the regulator will be shunting the excess voltage. However, if your car is running at 14V and your bike at 14.5V, the car isn't going to be causing any problem.

It's not about the car's system burning out the bike's system. It's about the car's system powering the bike so that the bike's regulator has to dissipate a much larger amount of the bike's alternator energy. This can put many times more stress on the regulator than it was designed to handle. It is the bike's alternator damaging the bike's regulator. The bike's alternator will also be getting hot and possibly damaged since it is running under a constant short/shunt condition.

It's not an all or nothing situation. Meters measure the average dc voltage, but doesn't show you the instantaneous voltage. The bike's regulator can start shunting with the system voltage as low as 13v, because instantaneous peaks could be reaching higher. By 14v, a large amount of shunting happens. If the car is putting out anywhere above 13v (maybe even lower), it will start having an effect on the bike regulator's dissipation load. By 14v it will be significant. This is true even if the car's voltage is slightly lower than the bikes voltage.

Another complication is that for a short time after a car starts, the car regulator can put out up to 15v.

This only affects Kz's using shunt regulators, but that is the majority of Kz's (and other makes and models of classic bikes). There is really no advantage to having the car running, and only potential downsides, so best advice is to not have the car running, just for simplicity.

It's not about the car's system burning out the bike's system. It's about the car's system powering the bike so that the bike's regulator has to dissipate a much larger amount of the bike's alternator energy. This can put many times more stress on the regulator than it was designed to handle.

Finally had an answer why jump starting from a running car could be a problem.

If it were from a car battery either disconnected or without the engine running then no problem.

loudhvx wrote: It's not about the car's system burning out the bike's system. It's about the car's system powering the bike so that the bike's regulator has to dissipate a much larger amount of the bike's alternator energy. This can put many times more stress on the regulator than it was designed to handle.

This I agree with - in fact I refereed to your post on the old thread on the matter.

loudhvx wrote: It's not an all or nothing situation. Meters measure the average dc voltage, but doesn't show you the instantaneous voltage. The bike's regulator can start shunting with the system voltage as low as 13v, because instantaneous peaks could be reaching higher. By 14v, a large amount of shunting happens. If the car is putting out anywhere above 13v (maybe even lower), it will start having an effect on the bike regulator's dissipation load. By 14v it will be significant. This is true even if the car's voltage is slightly lower than the bikes voltage.

Another complication is that for a short time after a car starts, the car regulator can put out up to 15v.

This I disagree with. You are correct that the regulator can 'spike' in voltage, but any battery attached will flatten out those spikes. You can simulate a battery as a power supply in series with a resistor and a capacitor - the battery's capacitance will smooth out the voltage spikes very effectively. On a related note, this is why you should never run a bike or car without a battery, as those voltage spikes can kill some electronics. It's also why a motorcycle battery eliminator is essentially just a capacitor. And I have never seen 15V on a car charging system, just started or otherwise. Some older cars can be as high as 14.5V (normal for a KZ) or normally closer to 14V. Unless you are referring to the charge voltage after turning the starter motor - in that case, the combined voltage of the battery and the regulator will still match the output regulator voltage (about 14V).

The power shunted isn't the power coming from the battery or the battery used for jumping, it's just the rectified output of the bike alternator. If the car voltage is more than the regulator requires, it will shunt the alternator voltage to ground - but that's still just the alternator voltage. The power coming in from the car will almost always be at a very steady voltage, and usually a much lower voltage than the bike's charging system.

If the car really is charging high (say 15V) then you can get the problems you mentioned. However that's no different to jumping from another motorcycle (or any other vehicle), where the output voltage is even more likely to be higher since the charge voltage of our old motorcycles is just higher. My KZ used to run at 14.8V, that would result in a lot more shunting than my car (about 14V).

But I think we can all agree that there is still no point in jumping from a running car.

One more question on the charging issue. When one buys a new motorcycle battery the instructions usually warn against charging the battery at a rate of more than 2 amps. Looking at the KZ650 Kawasaki Service Manual it appears the KZ650 normally charges at roughly 3 amps @ 4,000 rpm, so that's reasonably close to the warning. Since the alternator on a car or truck may be capable of producing 100 amps would that present a risk of damaging the motorcycle battery if the motorcycle battery was in a discharged state? Ed

Irish Yobbo wrote:

loudhvx wrote: It's not an all or nothing situation. Meters measure the average dc voltage, but doesn't show you the instantaneous voltage. The bike's regulator can start shunting with the system voltage as low as 13v, because instantaneous peaks could be reaching higher. By 14v, a large amount of shunting happens. If the car is putting out anywhere above 13v (maybe even lower), it will start having an effect on the bike regulator's dissipation load. By 14v it will be significant. This is true even if the car's voltage is slightly lower than the bikes voltage.

Another complication is that for a short time after a car starts, the car regulator can put out up to 15v.

This I disagree with. You are correct that the regulator can 'spike' in voltage, but any battery attached will flatten out those spikes. You can simulate a battery as a power supply in series with a resistor and a capacitor - the battery's capacitance will smooth out the voltage spikes very effectively. On a related note, this is why you should never run a bike or car without a battery, as those voltage spikes can kill some electronics. It's also why a motorcycle battery eliminator is essentially just a capacitor. And I have never seen 15V on a car charging system, just started or otherwise. Some older cars can be as high as 14.5V (normal for a KZ) or normally closer to 14V. Unless you are referring to the charge voltage after turning the starter motor - in that case, the combined voltage of the battery and the regulator will still match the output regulator voltage (about 14V).

The power shunted isn't the power coming from the battery or the battery used for jumping, it's just the rectified output of the bike alternator. If the car voltage is more than the regulator requires, it will shunt the alternator voltage to ground - but that's still just the alternator voltage. The power coming in from the car will almost always be at a very steady voltage, and usually a much lower voltage than the bike's charging system.

If the car really is charging high (say 15V) then you can get the problems you mentioned. However that's no different to jumping from another motorcycle (or any other vehicle), where the output voltage is even more likely to be higher since the charge voltage of our old motorcycles is just higher. My KZ used to run at 14.8V, that would result in a lot more shunting than my car (about 14V).

The battery does not smooth out the voltage enough to eliminate all ripple, so we are not talking about pure DC. It is DC with an AC component. This requires some sort of averaging circuit for the voltage detection. If we just set the detector to trigger at an instantaneous 14v, our batteries would be constantly draining and dead in a short time. (RMS voltage detection would have been nice, but too expensive and mostly unnecessary.) As such, the shunting must occur way before the instantaneous voltage reaches 14.2 or whatever the desired average voltage is. Also, by the nature of simple averaging circuits, it is also difficult to predict when a shunt will occur, exactly. A shunt, for a particular phase, can happen on the trailing edge of a ripple or a leading edge depending on what the other phases are doing.

After rewiring my Kz's, I usually see about 14..2 to 14.5v on the system. (I usually like 14.2 as a target average DC voltage) I usually see modern cars a few tenths higher. But it really doesn't matter. Shunting happens much earlier than either of those.

This link shows the shunting characteristics of the Kz (using the shunt type regulator). It also shows the voltage waveform of the bike's system voltage.
gpzweb.s3-website-us-east-1.amazonaws.co...rnatorWaveforms.html

From that link here is a screenshot of shunting happening at 12.9v (average). The average was only about 13v on the meter.
The screenshot shows several traces superimposed. Only one had the shunt event, as they are relatively rare at 12.9v, but do still happen. Actually, if you look very closely at the image, you will see a very faded trace of another shunt just to the left of center of the screenshot. So it is not an aberration to shunt at 12.9v. It is regular, even though it is neither frequent, nor predictable.

All else being the same, just a change in RPM can cause the regulator to shunt more or less frequently. The last two images on that link show the higher (3000 RPM) case is shunting more, even though the average DC voltage, as measured on the meter, is actually lower than that of the 2000 RPM case.

650ed wrote: One more question on the charging issue. When one buys a new motorcycle battery the instructions usually warn against charging the battery at a rate of more than 2 amps. Looking at the KZ650 Kawasaki Service Manual it appears the KZ650 normally charges at roughly 3 amps @ 4,000 rpm, so that's reasonably close to the warning. Since the alternator on a car or truck may be capable of producing 100 amps would that present a risk of damaging the motorcycle battery if the motorcycle battery was in a discharged state? Ed

If a battery is discharged, but otherwise ok, then yes, it will take quite a bit of amperage if 14.5v is forced onto the battery (not 100 amps, though). If a battery is fully charged, it will take less current if the same 14.5v is applied.

Charging lead acid batteries at work that are about 1/2 to 2/3 the size of what Kz550's or 650's might use, I find that once the battery is near fully charged, if 14.2v is applied, the charging current is only a few hundredths of an amp, like maybe .01 to .05 amps. But it's very sensitive, if you go down just a couple tenths of a volt, it's zero, or up a few tenths and the current can double.

That's why you really want to use a float charger if you are not very closely monitoring the charging (or a legit smart charger that does the monitoring for you). A float charger lets the battery's voltage "float" to whatever it wants to be. It does this by simply hitting the battery with small pulses of voltage/current (it's just a rectified, wall-transformer).

For our bikes, you would normally use a 2-amp float charger. "2-amp" does not mean it forces 2 amps into the battery, but it is a very rough, nominal value of the maximum the float charger will supply to the battery if it needs it. As the battery voltage increases, the current will drop down to tenths or hundredths of an amp. It will not drop all the way to zero, though, so even a float charger should not be left connected for days and days. Usually one day or so is all you need. Or just a couple hours if it was already charged, but was just sitting for a few weeks/ months.

Damaged batteries may take a large amount of amperage or no amperage depending on what's wrong with it.

I find car alternators usually charge the batteries to slightly higher final voltages than what you see in classic motorcycles, especially in colder temps. Car regulators are temperature compensated, but I'm not sure KZ's are. It's not expected someone would be riding in sub-zero weather. So if you wanted to charge a Kz battery (not connected to the bike) using nothing but a car alternator, you could simply put a resistor in series with the battery. Usually something like a 1 ohm, 1 watt resistor would do it.

Charging an uncharged, new battery in the bike is usually advised against. As you said, you might end up putting too much current into the battery if you get on the highway. But puttering around in a city, idling half of the time, it's probably safe. For many years I've charged new batteries both ways... some with highway riding in the bike, and some with trickle charging as prescribed. It didn't seem to affect the overall life of the battery, or the ability to crank the starter faster over the life of the battery. They all died in about 2 years. The last couple Scorpion AGM's lasted about 6.