1975 Charging question

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QWERTYMage

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The Apology
1st, I'm sorry I'm sorry I'm sorry for ANOTHER charging system question. I have no doubts that the answer to this question does exist somewhere in this board, but it's like finding a needle in a haystack. I have read through a few posts and there is SO MUCH info that I am more confused than when I started and it's only getting worse. My brain hurts now. Being that two different stator types exists has made this even that much more confusing.

The real question.
I have a stock '75 stator. I am testing to see if the green wire to the positive brush is damaged/shorted, etc. with a multimeter.7

When I test for continuity of the green wire (to make sure the wire is not broken and current does flow through it), I do get continuity. I test from the brush and both sides of the regulator connector block. I get .1 ohm resistance

When I test to make sure the green wire is NOT shorted, I have the power OFF and test at the connector block. I get no short (no continuity) to ground. I test for ground at multiple points (at my battery ground location, on the negative brush holder, and the engine case left side)

For this type of stator (The early one used with points), do these tests indicate a healthy green wire?

The reason I'm testing the wire, is my regulator isn't regulating as it should (charge went past 17v) and I am trying to troubleshoot my wiring before I send my reg/rec in for repairs (Oregon Motorcycle Parts reg/rec) to see why the reg may have gone bad. FWIW, OMP Tony has been very helpful.)
 
I would think the green wire is good. If it wasn't, you wouldn't charge at all. On your early type system, the regulator sends power on the green wire to the outer brush. That energizes the rotor and that makes the alternator put out a charge. The regulator stops or reduces the power through the green wire to stop or reduce charging output. Sounds like your regulator isn't doing that. Sounds like it's feeding power through the green wire too much of the time or all the time.
 
Never hurts to open the regulator and check that the points aren't stuck. Mechanical regulators are pretty simple.
 

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The Regulator is a solid state type. No cracking it open.

So, to be 100% sure, if the green wire was behaving as it should, putting a meter to the green and ground would not show continuity/short. Correct or incorrect?
 
BUMP.

"So, to be 100% sure, if the green wire was behaving as it should, putting a meter to the green and ground would not show continuity/short. Correct or incorrect?"
 
ok, this applies to any wire. With it unhooked at both ends
Le, touch your ohms meter leads to each end of wire. If continuity, ok. From either end to ground and get no continuity, ok.
So from what you said your green wire is ok.
Leo
 
The thing is you have a non stock regulator, there are several ways they can be wired to your existing stator. It's also possible that sometime during the life of the bike someone changed to a late model stator or did a nylon screw conversion.

70-79_XS650_CHARGING_LimeyBikes.jpg
latechargingdiagram.JPG
Early alternator generic schematic.gif
 
Here is another question, if the power is on (and power is put to the brushes, the green wire wouln’t show continuity to ground, right?

gggary:
Definitely no nylon screew conversion.

The reg (same maker and model) worked perfectly before i failed to connect the negative properly and cooked it a while back. The current reg is a repair to that one.

The stator may have been updated, but i doubt it. When i got the bike, everything except the pipes and tank were stock and original. The electrics were utterly neglected.
 
We're very lucky that the 650 uses a 3 phase alternator very similar to those used in cars. That means we can use low cost car regulators. No need to shell out $100+ for the fancy motorcycle specific items. Car regulators can usually be had for around $30 from the auto parts store, or as low as $10 on eBay.

Yes, there were 2 different stator versions used but the only real difference between them is in how the brushes are wired. The early version was used up through 1979. Your '75 would be this type if it hasn't been swapped or altered. The early version grounds the inner brush to the stator housing constantly through it's 3 mounting screws. The outer brush is fed power on the green wire from the regulator. The regulator switches that power on and off to control the charging output. The later '80-'83 style stator has the brushes wired just the opposite. The inner brush gets constant power from a switched wire in the harness. Any time the key is on, it will get power. The outer brush is fed the ground through the green wire from the regulator. The regulator switches the ground on and off to control the charging output.

So, as you've probably deduced, the 2 types of stators require different types of regulators to make them operate correctly. The older type needs a power switching regulator, the newer type needs a ground switching one. That's why it's so important to determine which type of stator you're dealing with. It will determine which type of regulator you must use. So that brings up the question - did you get the correct type of regulator for your system from Oregon Motorcycle Parts? A local guy had the later ground switching type regulator hooked up to his early stator on his '78. He had similar issues to yours, too much charging output.

Something else you can check is the voltage on the brown wire going into the reg/rec. This is power for the regulator but the regulator also "senses" the system voltage on that wire. That tells it whether to turn the charging output up or down, depending what it reads. You should get around 12 volts on that wire, about battery voltage. If it's reading low, the regulator would turn the charging rate up to compensate.

If the stator on your '75 is original and unchanged, here is what it should look like. The outer brush will have a small bracket and be attached with only one screw. The inner brush will have a larger bracket and be attached with 3 screws. Green wire to outer brush, black wire to the inner. The stator casting will have the timing and T.D.C. marks cast into it .....

BzlvmLV.jpg
 
Suggestion: Perhaps a photo of the alternator as per 5twins above and another of the regulator and its manufacturers code.

Thank you.
 
5twins,

Golly. Thank for all the help. really truly.

I'll give a bit of info: My stator looks identical to this photo you posted. Same brushes. Same marks.

Before this whole electrical mess happened, this reg/rec unit worked like a champ. I went on many rides with no problems, including a 300 mile run in a day and the system was great. Flawless.

This all started when I didn't tighten down the regulator's ground very well and it disconnected, fried the Lithium Ion Battery, which then sent a voltage/amp pulse uduring cookdown and fried a bunch of other parts including the regulator.

I replaced the battery and the reg wasn't able to do it's job due to unseen and undiagnosed damage. And it cooked the battery down again, taking more components with it. (To be honest, I was in a rush to ride and did not do a proper system check.)

So now I'm on my third battery and the regulator was repaired by OMP. Because of all the problems, I am testing and retesting and diagnosing everything that may go wrong before I commit to another cooked battery or worse. I ran the bike on the kickstand and it was holding the limit to 14.2v at 3500 rpm. Then after getting the courage (this has given me PTSD), I decided a stress test on the road was in order. I went out for a ride and my voltage went up to 17.3v about 4 miles out. I turned the bike off immediately, pushed it home (not fun but very educational), and put the battery on a tender (it is fine).

So now I'm testing everything again and all I can guess is that the regulator was a 1 in 500 bad unit. I think.

WITH THE POWER SWITCHED OFF, from both sides of the connector block, the regulator power wire to +brush has continuity and doesn't show a short to ground. The Neg wire to -brush has continuity. The brushes are adequately long and show resistance through the rotor, but to not show continuity (give a short/continuity tone) between one another (from brush to brush)

I tested all the wires, connectors, blocks and the reg/rec countless times in case I'm missing something.




My reg doesn't have a part number as it's made/assembled by a fellow here:

http://www.oregonmotorcycleparts.com/Reg_rec_units.html

The model is VRREM7-XS



5twins said:
We're very lucky that the 650 uses a 3 phase alternator very similar to those used in cars. That means we can use low cost car regulators. No need to shell out $100+ for the fancy motorcycle specific items. Car regulators can usually be had for around $30 from the auto parts store, or as low as $10 on eBay.

Yes, there were 2 different stator versions used but the only real difference between them is in how the brushes are wired. The early version was used up through 1979. Your '75 would be this type if it hasn't been swapped or altered. The early version grounds the inner brush to the stator housing constantly through it's 3 mounting screws. The outer brush is fed power on the green wire from the regulator. The regulator switches that power on and off to control the charging output. The later '80-'83 style stator has the brushes wired just the opposite. The inner brush gets constant power from a switched wire in the harness. Any time the key is on, it will get power. The outer brush is fed the ground through the green wire from the regulator. The regulator switches the ground on and off to control the charging output.

So, as you've probably deduced, the 2 types of stators require different types of regulators to make them operate correctly. The older type needs a power switching regulator, the newer type needs a ground switching one. That's why it's so important to determine which type of stator you're dealing with. It will determine which type of regulator you must use. So that brings up the question - did you get the correct type of regulator for your system from Oregon Motorcycle Parts? A local guy had the later ground switching type regulator hooked up to his early stator on his '78. He had similar issues to yours, too much charging output.

Something else you can check is the voltage on the brown wire going into the reg/rec. This is power for the regulator but the regulator also "senses" the system voltage on that wire. That tells it whether to turn the charging output up or down, depending what it reads. You should get around 12 volts on that wire, about battery voltage. If it's reading low, the regulator would turn the charging rate up to compensate.

If the stator on your '75 is original and unchanged, here is what it should look like. The outer brush will have a small bracket and be attached with only one screw. The inner brush will have a larger bracket and be attached with 3 screws. Green wire to outer brush, black wire to the inner. The stator casting will have the timing and T.D.C. marks cast into it .....

BzlvmLV.jpg
Click to expand...
 
Last edited:
Just a note on continuity: Continuity testing is really for wiring in a circuit without any resistive loads present. The lower the resistance the better the circuit quality. Poor connections add resistance to wiring circuits and result in voltage drops.

When using a multi-meter with continuity function the meter usually has a built in resistance requirement for the audio signal to work. For example, my meter on continuity will give the audio and simultaneous Ohm reading up to about 50 Ohms. If I test the continuity of a 100 Ohm resistor I get no audio but just a 100 Ohm reading. The Ohm reading tells me there is continuity but shows the state of the circuit with the resistance reading indicating how good or bad the connections are i.e. a resistance in the absence of any resistive load indicates a poor connection on a short length of wire as in a motorcycle harness. The lack of an audio signal just warns there is a significant resistance in the circuit.

When you measure continuity on the green wire with the rotor in the circuit it may show on your meter as a fault due to the rotors resistance. The resistance due to the rotor and brushes is very poorly defined when the rotor is stationary. So even though the rotor may be 5 Ohms and each brush 0.1 Ohm the combination may be much higher and then your meter may tell you there is no continuity even though the circuit is fine. Just an artifact of a stationary brush/copper ring interface.
 
Wow. Awesome. Great stuff to know. Brilliant.

That would be why I'm getting resistance readings (ohms) from brush/rotor/brush, but no continuity... Huzzah!

I'll read the resistance of all wires as well to make sure they aren't showing an odd level. What should the resistance look like for the green wire and the black wire from the brush holder to the connector block?




Paul Sutton said:
Just a note on continuity: Continuity testing is really for wiring in a circuit without any resistive loads present. The lower the resistance the better the circuit quality. Poor connections add resistance to wiring circuits and result in voltage drops.

When using a multi-meter with continuity function the meter usually has a built in resistance requirement for the audio signal to work. For example, my meter on continuity will give the audio and simultaneous Ohm reading up to about 50 Ohms. If I test the continuity of a 100 Ohm resistor I get no audio but just a 100 Ohm reading. The Ohm reading tells me there is continuity but shows the state of the circuit with the resistance reading indicating how good or bad the connections are i.e. a resistance in the absence of any resistive load indicates a poor connection on a short length of wire as in a motorcycle harness. The lack of an audio signal just warns there is a significant resistance in the circuit.

When you measure continuity on the green wire with the rotor in the circuit it may show on your meter as a fault due to the rotors resistance. The resistance due to the rotor and brushes is very poorly defined when the rotor is stationary. So even though the rotor may be 5 Ohms and each brush 0.1 Ohm the combination may be much higher and then your meter may tell you there is no continuity even though the circuit is fine. Just an artifact of a stationary brush/copper ring interface.
Click to expand...
 
How do you test an electronic regulator?

You cannot test the components in the regulator circuitry because they are encapsulated in resin. But, you can indirectly test for the regulators current variation in the green wire as the rpms increase. The current should decrease as the rpms increase. I know how I would attempt this but not sure if everyone would be up for it. In principle I would connect a very low value resistor in series with the green wire and monitor the voltage across it.

Alternately, I have a spare regulator and would swap it with the current suspect one.

If I were convinced that the circuitry was correct then 17V would tell me the regulator is not working......

I read an article several months back and one suggestion raised when the voltage is high is to check that the regulator's voltage sensor wire is at the same potential as the battery. If there were a 2.5 volt drop at the ignition switch and the regulator sensor is wired to the brown wire then the circuit is regulating for approximately 17V. Could this be the issue here???
 
The sensor wire was my second suspect... the first one being my negative wire not being hooked up properly. I checked the sensor wire at the connector block (to take the connector's resistance into account) and it came back good. (I don't know the exact number, but it was probably 1).
 
What you can try is to take a voltage measurement from the battery +ve terminal to the sensor wire when the ignition key is switched on. This will show if there is a voltage drop from the red wire through the switch and down the brown wire to the sensor wire.

Also, out of interest, what colour wire does the sensor wire of the regulator connect to on the harness - should be brown?
 
Curious, Did OMP repair your reg/rec under the warranty, or did you pay for the repair? I would just like to know what you get for just less than $150. Also curious about how he handles the next repair or exchange.

Thanks, Scott
 
Last edited:

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