Yet another charging system thread

spacetiger110

Fashionably sensitive, but too cool to care.
Messages
42
Reaction score
61
Points
18
Location
Sciota, PA
Let me preface this thread by saying that I am electrically retarded. I could probably do a top end rebuild without a shop manual or Google or anything, but electrical work just baffles me. I just don't get it.
I have a 1981 XS650 with the stock charging system. It's a tracker build, with turn signals removed, and aftermarket head and tail lights. I bought it like this.
Now, onto the charging issues. At 3k rpm, a battery charged to 12.5v reads 13v at the battery. I went through Curly's guide and took the following steps:
Passed slap test. Moved on to step 6.
All 3 combinations of white to white give me 6.5 AC volts at idle. Moved on to step 7.
Resistance on white to white is 2.5-3 volts for all three combinations. No change when yellow wire is unplugged.
With the yellow wire unplugged, I get an infinite reading from white to ground. With the yellow wire disconnected, all three are 27 ohms.
My understanding is that this data points to a shorted stator? Is this correct or am I overlooking something?
 

bikefreakjon

XS650 Addict
Messages
177
Reaction score
254
Points
63
Location
Idaho
If all three white wires have about the same resistance with each other and none of them are shorted to ground then your stator is ok.
 

spacetiger110

Fashionably sensitive, but too cool to care.
Messages
42
Reaction score
61
Points
18
Location
Sciota, PA
I'll have to open it up and check. I skipped all the rotor stuff because it passed the slap test.
 

5twins

XS650 Guru
Top Contributor
Messages
23,703
Reaction score
20,076
Points
813
I would start with the simple (and cheap) stuff - clean the slip rings and measure the length of your brushes. If the slip rings get too dirty, the brushes will lose contact with them. Also, if the brushes are worn too short, that will make them lose contact. For cleaning the rings, I pull the stator off and use plain old chrome cleaner on them. Here's one done (outer), the other not (inner) .....

GHoeRsM.jpg


After cleaning, be sure to wipe the rings down with some electrical cleaner to remove any polish remnants. A guy posted recently that he had problems with his brushes functioning after cleaning the slip rings with Mothers.

With the stator off, the brush springs should push the brushes out the back side. If they're originals, they will have a wear line etched into one side .....

PiJQ5jM.jpg


New length is about 14mm. The wear limit (and etched wear line) is at about 7mm.
 

spacetiger110

Fashionably sensitive, but too cool to care.
Messages
42
Reaction score
61
Points
18
Location
Sciota, PA
I would start with the simple (and cheap) stuff - clean the slip rings and measure the length of your brushes. If the slip rings get too dirty, the brushes will lose contact with them. Also, if the brushes are worn too short, that will make them lose contact. For cleaning the rings, I pull the stator off and use plain old chrome cleaner on them. Here's one done (outer), the other not (inner) .....

GHoeRsM.jpg


After cleaning, be sure to wipe the rings down with some electrical cleaner to remove any polish remnants. A guy posted recently that he had problems with his brushes functioning after cleaning the slip rings with Mothers.

With the stator off, the brush springs should push the brushes out the back side. If they're originals, they will have a wear line etched into one side .....

PiJQ5jM.jpg


New length is about 14mm. The wear limit (and etched wear line) is at about 7mm.
Brush replacement was the first thing I did before I even came across Curly's guide. I'll try cleaning the slip rings as you suggest.
 

spacetiger110

Fashionably sensitive, but too cool to care.
Messages
42
Reaction score
61
Points
18
Location
Sciota, PA
I would start with the simple (and cheap) stuff - clean the slip rings and measure the length of your brushes. If the slip rings get too dirty, the brushes will lose contact with them. Also, if the brushes are worn too short, that will make them lose contact. For cleaning the rings, I pull the stator off and use plain old chrome cleaner on them. Here's one done (outer), the other not (inner) .....

GHoeRsM.jpg


After cleaning, be sure to wipe the rings down with some electrical cleaner to remove any polish remnants. A guy posted recently that he had problems with his brushes functioning after cleaning the slip rings with Mothers.

With the stator off, the brush springs should push the brushes out the back side. If they're originals, they will have a wear line etched into one side .....

PiJQ5jM.jpg


New length is about 14mm. The wear limit (and etched wear line) is at about 7mm.
What do you use to polish? Just a rag?
 

5twins

XS650 Guru
Top Contributor
Messages
23,703
Reaction score
20,076
Points
813
Yep, just a rag and rub by hand. Cleans them up nicely. The slip rings get very dirty and black over time, and eventually the brushes lose contact with them. I've fixed a couple of non-charging bikes over the years just by doing this.
 
Last edited:
Top