Another charging issue...

[LMARJ2434]

Hi all,
I know I know, another charging issue, let me start by saying yes I have read everything there is on this forum and bikecliff there is about stators and R/Rs, I am also a technologist so know my way around electrical systems. So with out further hobbling about posting, I have an 81 GS650GL that I picked up a few weeks ago, was stone dead and sat dead for about a year or so and also bought a spare parts bike all boxed up for $200. The bike is now running but not charging great, looks like the previous owner changed out the R/R. I cleaned up the connectors and removed the headlight loop.

first test:
Stator check - average 1.3ohms per coil, OL on all coils to GND
starting voltage 12.7V
13.13V @ 1200rpm
13.22V @ 4000rpm
13.4V @ 5000rpm
between stator windings 30Vac at idle to 75Vac at 5000rpm

found a brand new stator in the parts bike possible from ricks electronics according to images on fortnine
Stator check - average 1.3ohms per coil, OL on all coils to GND
starting voltage12.72V
13.94Vdc @ 1200rpm
13.78Vdc @ 2500rpm
13.8Vdc @ 4000rpm
13.9Vdc @ 5000rpm
forgot to measure between windings

swapped the R/R from the parts bike, this was original factory so not hopeful, should mention also i trickle charged the battery between tests except for this one and took out for a short 30km rip day before
Stator check - average 1.3ohms per coil, OL on all coils to GND
starting voltage 12.42V
13.94Vdc @ 1200rpm
13.78Vdc @ 2500rpm
13.5Vdc @ 4000rpm
13.4Vdc @ 5000rpm
between stator windings 25Vac at idle to 83+Vac at 5000rpm

the lower voltage tells me the R/R is either breaking down and higher RPM or working harder to make up the small voltage drop from the starting voltage. I've searched everywhere for a reputable SH775 but not turning up much, any ideas or alternatives to the sh775 folks have had luck with?

[Rich82GS750TZ]

Ask Nessism if he has any SH775s. He sometimes buys good used ones, tests them on his bike and resells them. Maybe he’ll even ship to Canada. Don’t know.

[pdqford]

Are you taking those voltage readings at the battery?

If so, what do read at the R/R output?

And does anyone know if the GS650 has that nasty old splice about a foot into the main harness where the output of the R/R ties into the main Harness?

That splice on my GS750 was turning slightly green when I opened it up.

[Rich82GS750TZ]

OP wrote that he eliminated the headlamp loop.

[Nessism]

I have a few SH775's, but shipping to Canada costs money, and is buzz kill.

https://www.ebay.com/itm/384089812640

This one will save some money. Hook it up like shown, and you will know that the problem isn't the R/R.

SH775 Install by nessism, on Flickr

[LMARJ2434]

Are you taking those voltage readings at the battery?

If so, what do read at the R/R output?

And does anyone know if the GS650 has that nasty old splice about a foot into the main harness where the output of the R/R ties into the main Harness?

That splice on my GS750 was turning slightly green when I opened it up.

I pulled that loop and isolated those wires, I have my meter fastened directly to the battery, am I wrong to think the R/R line feeds back directly there as well?

[LMARJ2434]

I have a few SH775's, but shipping to Canada costs money, and is buzz kill.

https://www.ebay.com/itm/384089812640

This one will save some money. Hook it up like shown, and you will know that the problem isn't the R/R.

***edit, wait one just saw the 0.3v part in the drawing, for what it is I did cut out all the extra wiring and three extra plugs previous owner had in there (not sure what that was about) and the stator is directly connected to the R/R yellow wires using bullets I installed. I will check that red wire connection tomorrow, I replaced that bullet also but not sure about what is between that and the battery.

thanks again

SH775 Install by nessism, on Flickr

thanks Ed I can look at ordering that, shame I’m in BC, that seller is not too far from my old man’s place. You mentioned …” you will know that the problem isn’t the R/R” know I’ve read a lot of your comments and this forum, do you think I’m going the wrong way?

[LMARJ2434]

@Nessism I hooked up as per the drawing and measured an average of 0.15Vdc but it was pretty choppy so might be some badish wiring in there, thanks for that. I also measured from that R/R bullet to battery gnd as @pdqford indicated above once the bike was warmed up and did see voltages sitting around 14 at idle so that is pretty promising. Think the neighbors are getting tired of me reving the engine though so Im going to replace that section of wiring and report back over the next few days to the weekend. Thanks again

[pdqford]

OP wrote that he eliminated the headlamp loop.

Understood. But what I’m referring to is where the output of the R/R goes into the main harness on its way to the battery. At least on my GS750ET, about a foot into the main harness, the R/R output wire has a manual splice into the main harness. On my bike that splice was turning green.

Before the OP starts unwrapping the main harness, I was hoping one of the experts would know if the GS650 has that same splice or not.
Perhaps doing a proper voltage drop test between the R/R output terminal and the battery positive post should should indicate how much voltage is being dropped on that leg of the circuit.

[LMARJ2434]

Understood. But what I’m referring to is where the output of the R/R goes into the main harness on its way to the battery. At least on my GS750ET, about a foot into the main harness, the R/R output wire has a manual splice into the main harness. On my bike that splice was turning green.

Before the OP starts unwrapping the main harness, I was hoping one of the experts would know if the GS650 has that same splice or not.
Perhaps doing a proper voltage drop test between the R/R output terminal and the battery positive post should should indicate how much voltage is being dropped on that leg of the circuit.

Jim, I was wrong in my original assumption that the output went directly to the battery. I measured this morning off the bullet to the battery and saw about 0.15V on average, it was a little choppy. I did revert back to the aftermarket R/R the previous owner put on and measured what was supplied to the battery using that output and saw between 13.8 - 14V at idle. I didn't do the full test, was being pretty loud and had to get to work.

[LMARJ2434]

I put a new clutch cable in today, fixed my choke cable and tightened up the rear suspension so decided to go for a rip and did not do the full voltage test. I did however measure my battery before starting and came back after 35km with a nicely fully charged battery so i guess cleaning up the wiring harness did do some good. Thanks again all, loving cruising around Southern Vancouver Isalnd with this bike, almost feel bad for the young fella that sold it to me!

[Rich82GS750TZ]

You should look up trevor he’s in your neighborhood, has a garage full of nice bikes, at least 3 GSes of various vintages.

[trevor]

You should look up trevor he’s in your neighborhood, has a garage full of nice bikes, at least 3 GSes of various vintages.

Hey ya I just saw this....I'm in Victoria with 4 GS's
Cheers