(non)Charging system problem

[GS850Mike]

I just bought an 82 GS850g that is in really nice shape. The battery was dead when I looked at it, but it started and ran very well with a jump. After I got it home, I removed the battery and charged it up for a couple days. I reinstalled it and the bike started right up. But I noticed some smoke coming from under the battery so I shut it down. It was too dark to see where it was coming from. I went out today, it started up fine and ran well, but I saw the smoke again. I took some readings with a meter before the smoke appeared. The battery when disconnected was 12.34 volts. With the key on, it dropped to 11.78 volts. Running, the voltage did not change at all, even when revved. I found a black wire melted laying down near the swingarm, but did not see the other end of it anywhere.
Since the bike was running fine, I assume the stator is putting out current, but the regulator must not be allowing anything to get to the battery. Does this make any sense?
The r/r looks very clean for a bike that is 37 years old with 34,000 miles so I am assuming it was replaced at some point. It has markings on it, RS21 72 3332 8a28. Any ideas where this may be from? Any ideas where the black wire may have led, it is a fairly heavy gauge wire.
I know I'm asking a lot of questions without providing a lot of info, I would be happy with feedback as to where to go next.
regulator numbers.jpg

[Redman]

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Since the bike was running fine, I assume the stator is putting out current, but the regulator must not be allowing anything to get to the battery. Does this make any sense?...........

No.

Output of stator (3 phase volts AC) goes to the R/R and the R/R only.

Bike can run without the charging system at all, just that the battery will not be charging, so could run the engine untill the battery is too low to operate the ignition.

Your voltage reads do indicate that the charging system is not operating.

[Redman]

Only stock wire that is black is a turnsignal, but that is in a wiringharness most of the way along bike. And other black wire is the R/R negitive, but that is a short wire that is grounded at battery box on the solenoid mounting bolt.
Perhaps the wire you are finding is some added wire. Track it down, see if it has been addded to battery negetive. Maybe somevbody added it to better ground the R/R. Some failures of the R/R can dump a lot of current down its negitive wire.


TO check the stator. Disconnnect its three wires. Run engine at mid rpm about 4k. Have meter on VAC (not DC) scale, between each two wires should be about 70 VAC. Three sets of readings.
THere are checks of the R/R that you can do, with the diode check functions of some meters.
But basicaly if you have 3 phase 70 VAC on the stator test and are not getting 13.5 to 14.5 volts DC out of the R/R, then it is not functioning.

You are not charging at all, so something is complatley failed or disconnected.

[Redman]

Oh,
Welcome to TheGSR.

Opps, I forgot something. We need to see pic of bike before giveing any technical advise.
82 850G,... we need to know if the black one or the maroon one.
(joking) but we do like pictures of bike. WOuld be good to post an introduction in "owners" section.

[tom203]

Have a look further down in this section at the thread by " Qumodo"....he has similar issues

[Rich82GS750TZ]

Welcome

No doubt a previous owner tried to address a charging issue. It happens on all of these GSes. PO’s fix of a new (no better than stock) RR probably worked for a while. You will need to fix it better. You need to start with a new battery, you already know it’s not being charged, but report 6 numbers of the “quick test” to at least establish a starting point. Test your stator leg to leg at 5K RPM, and leg to ground, report those numbers. it will show if stator is bad but not conclusively that it is good.

You’ll need a new series type RR like a Shindengen SH775-can be found used <$50

You’ll need to clean up all the wiring. Establish a SPG. (Single point ground)

Quick test is linked in my sig. My charging system story is also linked in my sig. It may provide some insight. There are many threads here like it. Lots for you to read.

and post pics, we like pics.

[GS850Mike]

Thanks for the replies. I have read through the charging system thread previously, but as I started to go through the tests, I saw the smoke so I shut it down before there was more problems caused. Can I pull the connectors off the R/R to test the output of the stator? There is a 2nd wire attached to the negative terminal of the battery, maybe that is the melted black wire. That would make sense since it probably would not be fused. Did anyone recognize the marking on the R/R in the picture?rt side 3.jpgrt side 3.jpg

[Baatfam]

Nice looking bike....

[Rich82GS750TZ]

Not sure about the markings on that RR. Your going to want to replace that with either a SH775 or other series type RR from Compufire. Many, many post here about both. Don’t bother with anything else.

My bike has a heavy gauge black ground wire from a long bolt through the rear of the engine case, to my SPG where the other grounds are bolted to the frame. Then one wire to battery negative from the SPG.

Don’t know what to think about the smoke, but something sure is not connected properly.

[Rob S.]

Nice looking bike....

Yeah, but that's from the non-shaft side.

Sorry, no offense to all you shafties (how many friggin' 850s did they build?) I've been on the chain gang my whole life. I try not to look at the belt drive on my Sporty.

[GS850Mike]

I have been doing a bit of digging. Is the ignition a TCI or CDI system?
Here's the other side.
left side.jpg

[Baatfam]

Yeah, but that's from the non-shaft side.

Shaft side looks nice, also....

[Redman]

OKAY
Nice, all stock, original 850G.
Now we can help you.
(joking)

I am not that well versed to recognize the numbers on your present R/R.

Yes, disconnect wires between stator and the R/R to do the stator open circuit voltage test. and can also ohm check the stator also, should be just a few ohms between each pair of two leads, and open infinite between each and ground. Both these test can check good, but that doesnt mean entirely absolutely good, could be just barley good and about to completely fail. BUt if fails these test then know it is failed-burnt-crispy.

You can also disconnect the r/r positive wire (to main fuse wiring in harness if stock, or battery+ if someone did that) and r/r negative wire (to solenoid mount bolt if stock and/or battery negative if someone did that) and still can run bike. IF this elimates the "smoking wire" that will give you an idea it is the R/R and or wiring that is the problem.
CAn run bike with r/r completley disconected, just will not be charging the battery.

The talk here of changing to a different type of R/R is for an R/R that operates differently (called series regulator) and is easier on the stator so the stator last longer. That will require getting different wiring connectors and such.You decide if want to do that, or just replace what is there with similar.

[Redman]

I think the terms TMI and CDI do not apply here.

Ignition on 78 & 79 is the breaker points wire to the coils.
Ignition 1980 and after is the solid state pickup in place of breaker points, wired to an igniter (rectangular thin, metal case, mounted on side of battery box), and the igniter operates the coils.
And in this discussion, there is the detail of when was changed from mechanical advance to the advance function being in the ignitor, but I dont know that detail.

[posplayr]

Yes, disconnect wires between stator and the R/R to do the stator open circuit voltage test. and can also ohm check the stator also, should be just a few ohms between each pair of two leads, and open infinite between each and ground. Both these test can check good, but that doesnt mean entirely absolutely good, could be just barley good and about to completely fail. BUt if fails these test then know it is failed-burnt-crispy.

An ohm meter is pretty worthless for doing stator tests. Yes i know that is what is in the manual but the volt memet will not produce a voltage high enough to cause insulation breakdown. This is why you do leg to leg and leg to ground tests at 5K RPM when you shoudl have 70 VAc.

You can also disconnect the r/r positive wire (to main fuse wiring in harness if stock, or battery+ if someone did that) and r/r negative wire (to solenoid mount bolt if stock and/or battery negative if someone did that) and still can run bike. IF this elimates the "smoking wire" that will give you an idea it is the R/R and or wiring that is the problem.
CAn run bike with r/r completley disconected, just will not be charging the battery.

The talk here of changing to a different type of R/R is for an R/R that operates differently (called series regulator) and is easier on the stator so the stator last longer. That will require getting different wiring connectors and such.You decide if want to do that, or just replace what is there with similar.

I would just replace the R/R and clean up the wiring for ground and fuse box and then start over with a Quick test.

I have had a smoked ground wire which as best I can tell is because the R/R controlled one stator leg only (1981 GS750E).