charging system help

[diab]

Hi all,

I am trying to figure out why my battery isn't charging by following the charging guide in the tech section. I am getting stuck at the regulator test. The guide says to short the green wire to ground. How am i supposed to short that wire with the regulator plugged in? or a I supposed to have it unplugged for that test. Thanks!

 

[gggGary]

What year is your bike?

If it's a TCI (combined regulator rectifier) bike you can short it right at the brush. The regulator can stay plugged in.

 

[diab]

Its a 1980. Which wire would I short out at the brushes?

 

[gggGary]

The green wire. On your stator it should be the bottom brush.



You can just see the green between the clamps where the wire connects to the lower (outer) brush. Ground that screw head, the alternator should then put out full voltage, do not over rev the engine, or ground it for more than a few seconds.

 

[diab]

I just tried shorting the negative brush and it seemed to increase the voltage at the battery, but I realized my battery is not fully charged. So its charging now and I will check it again. If thats the case, before I replace the regulator, I want to check the ground wire on it to make sure it can be repaired. Which wire would I check there?

 

[EvenmoreXS]

CHECK THE GROUNDS. !!! I spent like 2 weeks chasing a charging gremlin when it was a loose ground. Did all kinds of reg/rec checks. Ground had continuity but was not grounding well. Moved the grounds to a better place....not on the swingarm......problem solved. Been great ever since.

My 2 cents.

 

[diab]

So I checked again, and grounding out the green wire didn't help. On the guide for the rotor check, it says to touch the leads to the brass slip rings. Are those the little rings held down by the brush screws? And for the stator test, where is the stator wire connector? I didn't see it where I thought it might be.

 

[diab]

CHECK THE GROUNDS. !!! I spent like 2 weeks chasing a charging gremlin when it was a loose ground. Did all kinds of reg/rec checks. Ground had continuity but was not grounding well. Moved the grounds to a better place....not on the swingarm......problem solved. Been great ever since.

My 2 cents.

Sorry but I wasn't sure. There are wires grounded to the swing arm? I didn't see any. Which ones are you talking about?

 

[gggGary]

No swing arm grounds, that was just his bike's issue. The slip rings are the big copper circles on the face of the rotor it's hard to get at the inner ring with the stator in place.
The stator connector is found by the frame backbone behind and slightly above the engine on stock bikes.

 

[diab]

Other than the ground strap, are there any other ground connections in the charging system?

 

[EvenmoreXS]

When rewireing my bike, I took a short cut,...also known as doing it wrong....and I ran my reg/rec ground wire to a threaded hole that was already on the top of my swingarm and I had a proper bolt to fit it, so thats where I put my ground. Worked for a week or so, but then ran into charging issues. After LOTs of trouble shooting the reg/rec and searching for a short,....I found nothing.....So I moved the grounds from the swingarm a few inches over to the the frame below the battery,...on the spine, or backbone if you will.... This solved the problem and have had NO issues since. DO NOT GROUND TO THE SWING ARM...EVEN IF ITS EASY TO DO...ITS WRONG...

Not that you did that, but dont make my mistake. A ground CAN cause your issue.

Good luck, you will get it,.. no doubt.

 

[gggGary]

Yes there are (from the factory) grounds all over the place, two or three up at the head/frame mount, the strap under the seat, one to the battery box/voltage regulator (rubber mounted) headlight, handlebars, tail light, turn signal stalks, horn, gauges, various relays, maybe a couple of others

 

[diab]

So I had a chance to measure the resistance on the rotor again and I am getting a resistance of infinity between the two slip rings. To be clear I circled where I measured in the attached picture. Does this mean my rotor is bad?

 

[gggGary]

Toast it is.

 

[XSLeo]

I might suggest removing the stator, cleaning the slip rings with very fine sand paper and electrical contact cleaner.
Some meter probes don't fit down into the holes where the brushes go. Removing the stator gives plenty of room.
You should get a reading between 4 and 7 ohms on the slip rings. 5 ohms is about ideal.
Also test from the slip rings to the nut that holds the rotor on. Should be infinity.
Leo

 

[diab]

So if I replace my rotor, then my bike should charge again?

 

[XSLeo]

If the rotor is bad then yes replacing it should make the charging system work, unless there is something else bad. Do all the testing you can.
Leo

 

[diab]

Is it possible to test the stator if the rotor is bad?

 

[XSLeo]

Yes, follow the wire bundle up from the stator. You will come to a large plug, unplug this plug. Next to it you will find a single plug with yellow wires. Unplug this wire.
Now looking at the big plug you will see three white wires, in your head number them 1,2,3. Use your meter on it's lowest ohm scale. Check the ohms on the white wires, 1-2, 2-3, 1-3. They should read all the same and be about .9 ohms.
Use the highest ohm scale and test from the white wires to the body of the stator. The reading should be infinity.
All these tests are in the charging system guide as well as in your repair manual.
Leo

 

[diab]

so i just remeasured my rotor and checked the stator. The rotor seems to be reading about 100k Ohms. the stator is reading between .8 and 1 ohms between the the three white wires. I'm assuming that this means the rotor is the cause, correct?