Charging gremlins

Bjorn

Bjorn

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Hi!

Rebuild my bike 4 years ago, always ran great until now. It's not charging and I could really use some help. Running the bike >2000 RPM results in 12,0 V.

I have red multiple topics on this forum trying to solve it, but no luck so far. Below a summary of the things I have tried/tested:

My bike: a mix of custom and stock parts. The wiring loom is not original but based on one i found here. Kick start only. Stock electronic ignition. Smaller battery.

Battery (aftermarket 4Ah):
- 11,8 V after barely making it home.
- Charged it to 13,5V. This slowly reduced to a stable 12,8V
- burned a bulb for an hour: battery remains at 12,8V (OK)
- Battery is keeping its charge of 12,8V for 2 weeks now (OK)

Brushes:
- slabtest: OK
- Voltage at the positive brush: 12,7 V (OK)
- Brush length: OK
- Measured from brush to ground: 1st brush: 8,8 Ohm. 2nd brush: 17,2 Ohm. Manual does not state anything. I do notice the big difference. (OK/NOK?)

Rotor (Stock):
- Slipring-slipring resistance: 5,5 Ohm (OK)
- either slipring - ground: ∞ (OK)

Stator (Stock):
- Resistance from White - white (3x) measured from connector: 0.8 Ohm (manual:0,46 Ohm). Please note that my connector is further away that on the stock wiring loom. (OK/NOK?)
- Yellow wire: removed from day one.
- Measured V ac at the white wires with connector plugged in @ idle : 3x around 13,4 Vac. (OK/NOK?)

Rectifier/regulator (Stock):
- Measured it according manual: OK
- colleague from work re-measured it: OK

Today i used my brand new car battery to check if it charges with that. Car battery: 12,5 V. Running the bike >2000 RPM: 12,0 V. This does rule out my motorcycle battery.

Anyways, electrics is not my strong point and im kind of lost here. Could someone point me in the right direction?
 
On your brushes, you say length is ok. What is the length. The book calls for a minimum of 1/4 inch. A lot have found that the brushes are worn out by 3/8 inch. Not so much the carbon part but the spring part. The springs get weak and don't hold the brushes against the rotor as well as they should.
I would replace then , they don't cost much.
I would also check your grounds.
Slab test? never heard of that one.
From the brushes to ground, never checked that. I think what you are finding is the ground path through the reg. The reg grounds the green wire to let current through the rotor. The differtence you find in the brushes is from the rotir ohms as well as the brushes to the rotor. One side crreads through just the reg, the othe aside through both brushes and the rotor.
Most anytime an electrical issue crops up checking any work you just did on the bike, grounds and wire connections is the first steps.
Leo
 
The brest way to measure is to remove from holder and measure the overll length of the carbon part.
I was being a bit sarcastic on the slab test. What you mean is slap test. Notice the last letter. Big difference.
I would still change the brushes. They don't cost much. Might even fix things.
Leo
 
XSLeo said:
- - - Slab test? never heard of that one. - - -
Click to expand...

Hi Leo,
just in case you are not being sarcastic, it's most likely a typo and the OP meant slap test
Where a feeler gauge or other steel object is "slapped" against the alternator cover to demonstrate that the rotor is producing magnetism.
 
Since this thread is still active:

I have a '75 with a pamco, stock charging system. It seems like I'll charge my battery, and a couple weeks later it'll be about dead (obviously, riding during those couple weeks). I just measured the brushes and one is about 9/16" and the other is 5/8". Could one being shorter than the other cause this? I've also been having issues with my horn, blinkers, and brake light and wasn't sure if any of this could be connected.

Also, it seemed the short one was angled on the end. Not sure on the other...

Thanks!
 
Last edited:
smiles79 said:
Since this thread is still active:

I have a '75 with a pamco, stock charging system. It seems like I'll charge my battery, and a couple weeks later it'll be about dead (obviously, riding during those couple weeks). I just measured the brushes and one is about 9/16" and the other is 5/8". Could one being shorter than the other cause this? I've also been having issues with my horn, blinkers, and brake light and wasn't sure if any of this could be connected.

Also, it seemed the short one was angled on the end. Not sure on the other...

Thanks!
Click to expand...

Those brush lengths are acceptable. You need to use a VOM to measure the voltage at the battery terminals
.
Measure with the engine off............engine idling............and engine at 3000 to 3500 rpm. Report back with the readings.

How old is the battery? If its a wet cell type, is the fluid at the correct level in the cells?

http://www.xs650.com/forum/showthread.php?t=10561
 
smiles79 said:
Since this thread is still active:

I have a '75 with a pamco, stock charging system. It seems like I'll charge my battery, and a couple weeks later it'll be about dead (obviously, riding during those couple weeks). I just measured the brushes and one is about 9/16" and the other is 5/8". Could one being shorter than the other cause this? I've also been having issues with my horn, blinkers, and brake light and wasn't sure if any of this could be connected.

Also, it seemed the short one was angled on the end. Not sure on the other...

Thanks!
Click to expand...

Hi smiles,
brushes are supposedly OK down to the wear lines and that's about 1/4" long and I read on this list that it's the springs not being able to push as hard when the brushes are worn down that far that stops them working.
So no, I don't see the brush lengths being the problem.
Mind you, the shorter brush being worn at a slant would make me check out the brush holder.
Me, I'd check every wiring connection and wire for continuity and that every ground wire was actually grounded.
 
Sounds plausible that one brush is longer than the other. The angular rotation of the rotor is greater towards the outside.
However angled brushes seems odd.
 
Bjorn what year is your charging system? I do not see that you have tried bypassing the regulator with a jumper

The quick tell if the top brush is only held by 1 screw it's a late system.

late rotor.jpg


like this.

As a test; jumper that top screw to ground, then what does your voltage read at 2000 RPM?

If the top brush is held on by two screws, AND they are not nylon screws.

xs650charging001.jpg


like this.

you have an early system.
To test this system; jumper wire the bottom brush to the positive battery terminal. Now check volts at 2000 RPM

If this test shows good charging, then the voltage regulator or wiring to it is probably the issue.




late rotor.jpg
 
PS VOM regulator tests only test the rectifier diodes inside, there is no VOM test of the "regulator" section of a combined regulator rectifier. The "jumper test" above shows that everything else in the charging system is working so the regulator is probably the bad component.
 
I have the ''late'' style charging system:
View attachment 55176

However I don't have any nylon screws on my assembly. I cannot find a parts diagram of the late style in the manual to confirm or deny whether this is correct... or not.

Just to be sure what should I be jumping:
1. the top brush to ground.
2. the reg/rec to ground? I assume I jump the green wire coming from the reg/rec directly to the ground?
 
Found it! Just rode 30k without problems. Battery is charging at 14,6V :D

This is the source of my trouble:
gremlin%252520found.jpg

This bullet connector came of while testing. replaced it and all the problems melted like snow in the sun.

Im going to rewire the whole bike from scratch using these superseal connectors
Amp_4_Way_Superseal_Connector.JPG
 

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