Slow battery drain

raimitm

raimitm

XS650 Enthusiast
Messages
44
Reaction score
22
Points
8
Location
NYC
New poster here, hoping someone can give me some pointers.

Recently bought a 83, all stock, missing starter button so I've been using kickstart only.
PO sold the bike to a dealership right before I contacted him, so I bought the bike from the dealership.
When I first went to buy the bike, it wouldn't hold a charge at all. The dealer kept the price and offered
to fix the charging problem. He replaced the rotor and battery. The bike started up no problem, all lights working. Everything seemed fine until after about 5 or 6 hours of riding, the bike died and wouldn't start up. Someone pulled over and helped me troubleshoot the bike, and found the battery voltage was at 9.
I had to get a tow home, bought a charger and voltage meter. I just put in the fully charged battery and the bike starts right up, stays at 12.1 idling but when i rev it the voltage doesnt go up at all, just stays at 12. Does anyone have any ideas based on the fact that theres a new rotor installed, and that i was able to ride for that long before it died at 9V? Guessing its either the stator, regulator, or a short somewhere. Going to follow the charging guide and try to determine the problem but some advice would be very much appreciated. Thanks!
 
Yes, assuming the replacement rotor is good (test it), it would have to be one of the other things you mentioned. Also check brush lengths. They are a wear item and once they wear too short, charging rate reduces or stops completely. There is also a rectifier combined with the regulator. That could be bad.
 
Follow the charging guide step by step with a good multimeter and you will find the problem. The problem should be fixed by the dealer since you mentionned they would fix. Get your hands dirty and find the source, then tackle the dealer.
 
I followed the guide and found a few things. Let me know if this shows the source of the problem.

When idling, V goes up to 12.3 then back down and up inconsistently, doesn't go up past that mostly stays around 12
Slap test is very weak with the case on. I took off the case and found this circle which seems to be the only part of the rotor
that is magnetized.

Resized_20180726_173701.jpeg


I unplugged the stator connector and none of the male ends make a connection when touching 2 of the 3 ends with a multimeter.

On the female side, only the bottom receptor makes a circuit with the + battery terminal.

Tested the regulator connector and that is fine. Tried revving while the regulator is bypassed to ground and no difference.

Another thing is I cant get a read on the rotor, seems like the rotor is no good.
 

Attachments

  • Resized_20180726_172523.jpeg
    Resized_20180726_172523.jpeg
    87.2 KB · Views: 170
  • Resized_20180726_172505.jpeg
    Resized_20180726_172505.jpeg
    72.6 KB · Views: 151
5twins said:
Yes, assuming the replacement rotor is good (test it), it would have to be one of the other things you mentioned. Also check brush lengths. They are a wear item and once they wear too short, charging rate reduces or stops completely. There is also a rectifier combined with the regulator. That could be bad.
Click to expand...
Checked the brushes too, they're fine, looks like they were replaced pretty recently.
 
U have to take the brushes out. Pay attention how the one brush twists and then raps around before going into the holder.
 
You're also testing incorrectly. You have both meter probes on the same slip ring. That won't tell you anything. There's a second slip ring closer to the center of the rotor. It's difficult to see with the alternator installed, difficult to reach and test to as well. Here's what the rotor looks like with the alternator removed. You test between the 2 copper colored rings .....

jrGGd3G.jpg
 
The plug you have shown looks like the pickup plug that goes to the ignitor box which fires the coil. You should be looking for a 6 pin plug for the stator and test the white wires. The slap test is only magnetized with the battery on. Read carefully and you should have a wiring diagram or manual to refer too.
 
5twins said:
You're also testing incorrectly. You have both meter probes on the same slip ring. That won't tell you anything. There's a second slip ring closer to the center of the rotor. It's difficult to see with the alternator installed, difficult to reach and test to as well. Here's what the rotor looks like with the alternator removed. You test between the 2 copper colored rings .....

jrGGd3G.jpg
Click to expand...
Ok thanks, I'm going to test it again. The only video i found on it i couldn't see the points he was touching. Thanks for the info!
 
Here's something that you might want to try. Get a 6V 6W bulb and temporarily wire it in series with your rotor (either end). This bulb will have a resistance about the same as the rotor. The regulator won't mind having this bulb in the circuit. You won't get full output from your generator while the bulb is there but it'll be good enough to see if its working. It won't be bright unless the regulator calls for decent output so you might need to do something like turning the brake light or headlamp on. It'll be brightest at low RPM, it's not a problem if it gets dim as you rev and the regulator throttles back.

You can use it as a visual check for everything in your rotor circuit:
  1. It won't light if your regulator is unable to operate the rotor as it should (the bulb lighting doesn't prove your regulator is entirely good though).
  2. It won't light if your brushes are not making a good contact.
  3. It won't light if your rotor is open circuit.
  4. If it pops, your rotor is shorted or too many turns are shorted.
  5. You can measure the voltage across the bulb - it should be about half the battery voltage if your regulator is calling hard for output and your rotor/brushes are good.
  6. You'll be able to see if you have an intermittent problem.
NOTE: I haven't done this on my bike. But it won't do any harm and might help if you have multiple problems and aren't getting anywhere. And it frees up your multimeter.
 
Not trying to add to your issues, but your picture of the slip ring on the rotor makes me think that the stator housing may be rubbing on the rotor. A new rotor should look shiny and clean, not scratched up like the picture. I had this happen recently when I replaced a rotor. The new rotor had a layer of varnish inside of the taper where it mounts to the crankshaft and it made the rotor stand out too far and contact the stator until I removed it and cleaned the varnish out of the tapered hole. Fortunately, it did not damage either component beyond repair. If you try to do this yourself, you will need the rotor puller tool. Don't try to remove the rotor without one. Good Luck.
 
toomuchstuff said:
Not trying to add to your issues, but your picture of the slip ring on the rotor makes me think that the stator housing may be rubbing on the rotor. A new rotor should look shiny and clean, not scratched up like the picture. I had this happen recently when I replaced a rotor. The new rotor had a layer of varnish inside of the taper where it mounts to the crankshaft and it made the rotor stand out too far and contact the stator until I removed it and cleaned the varnish out of the tapered hole. Fortunately, it did not damage either component beyond repair. If you try to do this yourself, you will need the rotor puller tool. Don't try to remove the rotor without one. Good Luck.
Click to expand...

I was wondering about those scratches. Just ordered a rotor puller, going to try to clean it and re install it correctly. What would you use to clean those rings? Or is it better to just get a new rotor? Cant get a reading on the rotor ring blocked by the alternator anyway, I'll see when i get it off. That could be the problem.
 
The bike me and my buddy are working on now wasn't charging when we got it. The guy took it to a shop to get it fixed and right off the bat, they replaced the brushes (did a shit job too, lol). That didn't fix it. They said they could continue on and start replacing various electrical components but the guy didn't want to have to be putting all kinds of money into it. He took it home and parked it. That was like 12 years ago, lol.

We knew the bike had charging issues and we knew we could fix it, it was just a matter of how much it would cost (what needed replacing). First step was to remove the whole left cover so we could inspect all the alternator wiring. The probable issue jumped right out at us. The guy hadn't properly routed the alternator wiring loom and the chain was cutting into it .....

PT0A2JD.jpg


zPRZYsq.jpg


I repaired the cut wires and she's a charging fool again. Well, almost. The bike charged alright but too much, putting out 16 volts when revved. I guess the cut and shorted wires screwed up the regulator somehow. Swapping on a used reg/rec unit fixed it and brought the charging rate down to a more acceptable around 14.

So, look at all the simple stuff first. Pull that big left cover off so you can see all the alternator wiring.
 
Those "scratches" on the rotor seem normal when the brushes are rubbing on those copper slip rings and the black looking stuff on the slip rings is carbon off the brushes. I have used chrome cleaner or autosol to clean up the slip rings. Just take the left engine case along with the stator to expose the rotor.
 
Finally got my JIS screwdrivers and got off the part that holds the brushes to get an accurate test of the rotor between slip rings. Theres no resistance between the rings. Just shows open line. Also tested continuity and no beep.

I followed the guide to test the stator and tested AC voltage while idling.
Shows 0 AC on each of the fabric covered side of the wires (while connected)

Disconnected, checked resistance for each plug for the white wires on male side,
all show 0.9

For the regulator, with the key off i tested DC voltage from red wire to battery ground, 12.7
With the key on the black wire to battery ground reads 0.01
Green wire to ground is open line.

Looks like problems in all areas.
Only thing i haven't done is open the left case, do i need to remove the footpeg and shift lever?
Any ideas on what to do next? I guess the PMA kit is worth it at this point.
Thanks everyone for your responses!
 

Similar threads

N
Odd charging problems on '75 xs650
Replies
8
Views
211
Its been a long time
I
2XSive
Over-charging? Reg/Rec Mod
Replies
5
Views
394
2XSive
2XSive
JNaw
Rotor melted itself 500km after rewind?
Replies
15
Views
345
JNaw
JNaw
freddy3
Dropped side cover, now she won't charge
2 3
Replies
54
Views
3K
freddy3
freddy3
G
Weak charging system or mechanic with weak skills?
2
Replies
23
Views
1K
Jim
Jim
Back
Top