Charging woes

[Guest]

1980 GS750. Battery wasn't charging. Replaced the battery with a good one. Started the stator pages. The volts will not increase when increasing the idle, at 2500 and 5000 the voltage is the same as idle (12.30). I proceeded to the Ohms test for the stator and came up with 2.0, 2.5, 2.4. I moves onto the AC test but couldn't get a reading with my multimeter (I think I was doing it right though). Any ways I replaced the stator and low and behold I get the exact same result with the quick test. Everything looks fine until I increase the rpms, the volt reading stays the same as at idle. I also replaced the R/R with a new one with no benefit. Any help is appreciated.

 

[bluewool]

First thing I would do is confirm that my multimeter was working. When you begin to question your diagnostic tools you cannot trouble shoot.
You should get AC out of your new stator.
Did you run the diode test on the old R/R?
Are you checking the voltage at the battery of at the R/R?
If you're checking at the former it could be the wiring from the R/R to the battery, if you are checking the later a bad R/R, Or bad connections/wiring from the stator to the R/R(but this is the leads on the stator- no?)

 

[Guest]

Just as a note, the bike was running and charging fine. We Vacuum synched the carbs and the next day this happens. I was hoping it was a loose wire but have not been able to find anything. The diode test on the R/R showed fine. I am checking the voltage at the battery.

 

[bluewool]

Start at one end and work to the other..

Check for AC at the stator leads.
Check voltage at the R/R AC input.
Check voltage at the R/R output.
Check voltage at Battery.

I would say the sync is a red herring.

 

[posplayr]

In just fixed a bike this weekend that sounds remarkably similar to yours. It only require changes to connections and grounds. See gs charging system health in my signature

 

[Guest]

In just fixed a bike this weekend that sounds remarkably similar to yours. It only require changes to connections and grounds. See gs charging system health in my signature

My first thought with this problem was wiring. But doing the testing and it showing no voltage increase at all when increasing the RPM's made me think there is no way it could just be the wiring. But is that actually possible?

 

[posplayr]

Yes the bike this weekend did a quick test
12.8 key off
12.4 key on
12.5-12.6 1500
12.8-12.9 2500 max
12.4-12.5 5000 max
after mods
Bike charged at high 13v at elevated idle and 14.5v at 2500 rpm+
Voltage drops both positive and negative were less than 0.1v

 

[Nessism]

The main problem with the GS charging system is the wiring: the R/R grounding scheme is BAD, and the stator power routing though the main GS harness takes a BAD PATH (up though the LH hand control); resistance builds in the various connections which adds heat and eventually releases smoke.

Number one thing to do with the charging system is FIX THE WIRING. This should be done before the system fails, and is dead easy to do.

Route the stator wires directly into the R/R, bypassing the factory harness. Keep the wires as short as possible. Next, make sure the R/R is solidly grounded. NOT to the battery box or similar. Ground the R/R directly to the battery or a solid frame point.

Last thing is make sure the Power feed out of the R/R has a low resistance path to the battery. Pos's instructions detail how to test. One simple solution is to just run the R/R positive output directly to the battery, with an inline fuse. Very simple solution and fool proof.

Regarding diagnosing the system after the fact I think the Stator Papers is more difficult than it needs to be.

1) check for AC output from the stator.

If stator output is below 70 volts, replace the stator. If stator output is good, hook up the R/R as detailed above and check the charging voltage. If it's less than 14 volts your R/R is bad. I wouldn't even bother to check the system until both the wiring and R/R grounding issues are FIXED. Fix first, measure second, replace parts as needed third.

 

[Guest]

Thanks Bluewool, Jim and Ed. Sure appreciate your expertise in this stuff. I'm going through the wiring as we speak. I had to laugh at myself though. I thought to myself this morning, "If someone else posted this problem what would you suggest? clean up the wiring, grounds, R/R, Stator then test things" Funny how I can't follow my own advice sometimes.

 

[Guest]

Well, cleaned all the connections/grounds. Rewired the R/R and did the single ground mod. Also ran a fused wire directly to the battery for the R/R. Still can get the volts to go up when increasing the RPM's. Arrrr.....My volt meter blew a fuse so I'm off to get a new voltmeter to test the volts on the stator..arrr...

 

[bluewool]

Well, cleaned all the connections/grounds. Rewired the R/R and did the single ground mod. Also ran a fused wire directly to the battery for the R/R. Still can get the volts to go up when increasing the RPM's. Arrrr.....My volt meter blew a fuse so I'm off to get a new voltmeter to test the volts on the stator..arrr...

Um generally only the current is fused on a multimeter... are you certain you have the leads in the correct holes. And I really don't mean to song like an ass, it's just sometimes we all make these obvious errors. I cannot count the number of times my meter has growled at me when I put it on a live circuit while set on ohms.

 

[Guest]

So, new multimeter just to make sure. The volts at the battery remain the same (won't go up past 12.28 when reving up to 2500 or 5000). I tested the stator with ohms when it was on the bench and it read 1.7 on all three leads (but that was with the old multimeter). Put it in the bike and tested it with the new multimeter and got 0.5 on all three. Did the resistance test to the frame and all three leads showed infinite. Did the AC volt test and could only come up with 2.4 V for each lead when set to 200 on the AV volts (the lowest setting on this multimeter). I'm guessing the stator is toast. The odd thing though is it was a new stator last September and has only 8000kms on it. Was new from a company in Quebec I think. I'm 'pretty' sure it's the stator that is gone (I know for sure it's not the R/R as all it's tests come out fine and I even put a good one in with no better results on the quick basic test). So like I said, I'm 'pretty' sure it's the stator. I just feel odd diagnosing it as a failed stator when the stator is only 8000KM's old.

 

[bluewool]

So, new multimeter just to make sure. The volts at the battery remain the same (won't go up past 12.28 when reving up to 2500 or 5000). I tested the stator with ohms when it was on the bench and it read 1.7 on all three leads (but that was with the old multimeter). Put it in the bike and tested it with the new multimeter and got 0.5 on all three. Did the resistance test to the frame and all three leads showed infinite. Did the AC volt test and could only come up with 2.4 V for each lead when set to 200 on the AV volts (the lowest setting on this multimeter). I'm guessing the stator is toast. The odd thing though is it was a new stator last September and has only 8000kms on it. Was new from a company in Quebec I think. I'm 'pretty' sure it's the stator that is gone (I know for sure it's not the R/R as all it's tests come out fine and I even put a good one in with no better results on the quick basic test). So like I said, I'm 'pretty' sure it's the stator. I just feel odd diagnosing it as a failed stator when the stator is only 8000KM's old.

RM STATOR. They make a crappy stator, but it's still under warranty.

 

[Guest]

RM STATOR. They make a crappy stator, but it's still under warranty.

It looks like Ricks is the one to go with. I'm hoping to find a Canadian supplier for one. Turns out Winners Circle Motorsports in Ontario is the only Canadian supplier. They're asking $179 compared to Ricks at $140.

 

[bluewool]

I actually don't remember what brand I put in the 1150 last summer after I removed the smoldering RMstator. It was powder coated may have been Rick's but I think it was Electrosport? Yeah. It is an Electrosport, I have heard terrible things about them too.
I was skeptical of the RM as soon as I saw it. The Electrosport looked like a much better quality product. I have about 10k/km on it with a cycle electric R/R. --- which is gigantic.

 

[Guest]

Problem solved. Put in a used but working stator and everything is charging properly on the simple test. Stator is putting out 1.2 ohms and 95 volts evenly across all three leads. So bikes running great again, and it gives time to order the new stator without having down time..win, win. Now that you mention R/R sizing, the one on the bike has been replaced last year but it's small, again it's the one from RM stator. There's not much info on their site about it. I'm thinking that if the R/R was too small for the job at hand it would ruin the battery over time but shouldn't do any harm to the stator, sound right? Maybe this is a mute point. Again thanks for all the help everyone. Another GS back on the road.

 

[BassCliff]

Good going Rob,

I'm not a fan of RM Stator either. They were nice enough to warranty my first purchase from them (fail after 4 months) but then the replacement failed just out of warranty. Maybe it's just my bad luck.

Glad you got your bike charging again. Now get out there and ride.

Thank you for your indulgence,

BassCliff

 

[Guest]

Two stators in 18 months, yikes. I'm a bit worried about the R/R now since it came from the same place, and it's not my bike Cliff, it's Trevors and we're both glad it's back on the road.

 

[BassCliff]

Rob,

I wouldn't worry too much. Keep all the charging system connections and grounds clean. It should be OK. Perhaps my charging system wasn't as clean as it could have been. Good luck.


All the best to you and yours,

Cliff

 

[850 Combat]

Yes the bike this weekend did a quick test
12.8 key off
12.4 key on
12.5-12.6 1500
12.8-12.9 2500 max
12.4-12.5 5000 max
after mods
Bike charged at high 13v at elevated idle and 14.5v at 2500 rpm+
Voltage drops both positive and negative were less than 0.1v

In my personal experience, voltage drop at higher RPM's as you show here have been fixed by taking care of by fixing grounds and connections. One time it didn't. That bike wasn't mine, and the owner sold it.