1982 GS750T - R/R Connector Help Required...

[pdqford]

I'm also struggling with your wire colors and your 6 terminal white connector.

What does/was the white connector connected to?

I don't see a 6 terminal connector connected to a Regulator in the wiring diagram.
And the three yellow wires makes me suspect that this bike's wiring has been modified.

Take a picture to include the fuse block with it's cover off.
Sorry I haven't been more help as I don't want to send you down the wrong rabbit hole.

 

[Rich82GS750TZ]

The white connector was put in by the PO. It doesn’t belong. The red/black coming from the bottom of the fuse box is also not factory. That’s why we’re having a hard time telling you exactly. What to do with it.

 

[SamLack99]

Hi Guys,

As requested...

...Here's a picture including the fuse block with its cover off.

I've also included a YouTube video shot on my phone that might (or might not) help.

Looking forward to your feedback =)

Thanks again.

 

[Rich82GS750TZ]

You are correct on the 3 yellow from the stator to the new 3 pin connector to the left (gray) side on the SH775, You are also correct about the Ground wire that will go the the right pic of the right (black) side of the SH775.

For the red - Best I can do is state what I BELIEVE. This could be very far from what is TRUE. I BELIEVE the Red w/ Black tracer wire in your pictures coming from the fuse box could have been added by the PO as a sense wire that was needed by the SH555-12. I really don't know. There is no such feed for the SH775. So, I BELIEVE you should eliminate it. (# TWO in your diagram - post # 20). I mean de-pin it from the block at the bottom of the fuse block. Whatever, the block this wire and the 3 yellows went into was put in by the PO specifically for the SH555-12. Remove it. It no longer belongs. It can't clip into the SH775 anyway, And Wire the positive left wire of the SH775 right (black) side to the remaining red wire (# ONE in your diagram- post # 20) . But you really should unwrap some of the harness and see that there is an inline fuse.
The pics below are what the plug going into the bottom of the fuse box looked like on my 750 T. Never-mind the ugliness. I later cleaned up all terminals and installed a new block. But the orientation and colors of the wires is correct.

NONE of this accounts for the possibility that this could be a British Market Bike. I don't think it is. I think the T was a NA only model and someone imported it to the UK. But just putting that out there.
NONE of this accounts for the possibility I could be completely wrong. Re-working a PO's re-working of your bike's electrical system is the worst to try to diagnose over the internet. I can't put a voltmeter to anything. I'm I'm not sure I could guide you any further even if I could.

Hopefully someone else will chime in to either agree or disagree with a better resolution. Here are the pics of the bottom of the fuse box connector as it should look (more or less). It looks to me in your pics that you have NO wires coming out of the the Right side slots of this block, and I have 2 Reds. That's what is really making me question what is going on here.

 

[SamLack99]

Thanks Rich.

The 'T' was a USA only bike, mine was imported a long time ago.

At least I know what I'm doing with the three yellows and the black.

Just got those pesky reds to sort out.

Alternatively, I can always assume the PO knew what they were doing and simply get a new 6-pin connector and go back to the SH555.

We'll see.

Thanks again Rich =)

 

[Rich82GS750TZ]

Alternatively, I can always assume the PO knew what they were doing and simply get a new 6-pin connector and go back to the SH555.

If it ran, and charge the battery while doing so, that is an option. If it wasn't charging or was charging poorly, I'd continue down the path you've already started. Good Luck. Really wish I could help more.

 

[pdqford]

Thanks for the pic of the fuse box.

And I think Rich is right on!

I am trying to sort out your wire one and two but am getting another headache.

Before I strain my brain again, I need to be sure:

What does/was the white connector connected to?

​

Does it connect directly into a six pin R/R, or is there more wires between that white 6 pin connector in your pictures and the R/R?

Do you know if the bike ran and charged with the PO's wiring mods?

And can you trace out the wire(s) attached to the positive battery post?
(One should go to the starter solenoid. If there is another wire, what color is it and where does it lead to?)

Whoa....that's five questions and I am already confusing myself......:chargrined:

 

[SamLack99]

Hi Jim,

Thanks for your reply.

1. The white connector connected directly to the old SH555 R/R. No extra wires.
2. I don't know if the bike ran and charged with the PO wiring mods, the guy I bought it from didn't make those mods and bought it as a project. How much of a project I don't know, he's since died of cancer so I can't ask. I bought the bike because I liked the look of it and I knew he was trying to raise cash for his soon to be widow. He said it ran, but I never saw it and I never got it running.
3. As for tracing out the wires attached to the positive battery terminal...

...I'm gonna have to do some research into that and get back to you tomorrow. I took pictures of everything before I took it apart, and it's way past my bedtime =)

I'll get back to you with that information after work tomorrow.

Thanks again for sharing your experience and for being prepared to encounter a headache helping me to solve mine =)

Night night.

 

[SamLack99]

Finally...

...Here's a video of me tracing the wires that were attached to the positive battery post.

Hope it helps to shed light on the next steps for fitting the SH775 R/R =)

Many thanks

Marcus

 

[pdqford]

PLEASE IGNORE THIS POST.
SEE THE NEXT POST!

Okay Sam, thanks for that video.

One thing I am not sure about is why your white 6-pin R/R connector wires are different from the picture Rich posted of his white 6-pin R/R connector wires. Don't you both have T's?

Based on this pin-out of a 6 pin connector:

https://images.app.goo.gl/v3kPe4sGrhKHYp3n6

it appears to me that the typical pin layout of a 6-pin R/R puts the three stator wires together, while the other three pins represent the R/R power out pin, the R/R ground pin, and the R/R sensing pin. So the yellows from the stator go to the lower three pins of the R/R.

That leaves us with those upper three pins on the R/R. And the B/Y looks to be the ground.

I suspect the two red wires represent the power wire out and the sensing wire.

So here is how I believe the the other red wires (three of them!) function.

The smaller red wire that connects to your battery + post and goes into the main harness carries power up to the ignition switch.
When the ignition switch is turned on power comes back down the main harness on a orange wire into the fuse box to power up the fuse box which powers up that R/B wire that you show going from the fuse box to the center pin on your white connector and then into the center pin of the R/R so that the R/R can monitor system voltage.

To prove this out, break out your ohm meter. Connect one probe to that smaller red wire that comes from the battery + post, and the other probe to the R/B wire (your WIRE TWO) going from the fuse block to the center pin of the white connector. There should be no continuity. Turn the ignition key on and there should be continuity. ergo: the R/R sense the system voltage!

The final red wire (the one you referred to as WIRE TWO) that goes from the upper left pin of the connector into the main harness is the R/R power out wire from the R/R. Within the main harness that power out wire is spliced into the smaller red wire that goes from the battery to the ignition switch. That allows the R/R to supply power to the ignition switch (and the vehicle electrical load) and/or to the battery to charge the battery.

To prove this out, break out your ohm meter. Connect one probe to the smaller red wire that connects to the battery + post and the other probe to the power out wire from your white connector. Should always show continuity.

So that's how I figure the PO had the bike wired. No guarantees !
Hopefully it will make it easier for you to go from the current wiring to the one that Nessium reccomends.

And I hpe someone will come along and check to see if I maybe I made some wrong assumptions.

 

[pdqford]

My bad! I just found the wiring diagram for the T, so I'm going to modify my previous post.
I surly didn't mean to make this even more complicated by trying to revise my previous post, but here goes.

Okay Sam, thanks for that video.

One thing I am not sure about is why your white 6-pin R/R connector wires are different from the picture Rich posted of his white 6-pin R/R connector wires. Don't you both have T's?

Based on this pin-out of a 6 pin connector:

https://images.app.goo.gl/v3kPe4sGrhKHYp3n6

it appears to me that the typical pin layout of a 6-pin R/R puts the three stator wires together, while the other three pins represent the R/R power out pin, the R/R ground pin, and the R/R sensing pin. So the yellows from the stator go to the lower three pins of the R/R.

That leaves us with those upper three pins on the R/R. And the B/Y looks to be the ground.

I suspect the two red wires represent the power wire out and the sensing wire.

So here is how I believe the the other red wires (three of them!) function.

The smaller red wire that connects to your battery + post and goes into the main harness carries power to the fourth fuse down (labeled MAIN) in your fuse block.
(I don't know why it is a 10A fuse as it originally was a 15A fuse.) That MAIN fuse feeds power thru a red wire that goes up to the ignition switch. When the ignition switch is turned on, an Orange wire brings power back to the fuse block and powers the top 3 fuses (which were originally 10A fuses).

I assume the R/B wire that you show going from the fuse box to the center pin on your white connector and then into the center pin of the R/R is powered by the MAIN fuse so that the R/R can monitor system voltage. (I'm not sure that it is a good idea for the R/R sensing wire to be powered all the time - even with the bike off).

To prove this out, break out your ohm meter and put one probe on the R/B wire (your WIRE TWO) going from the fuse block to the center pin of the white connector and the other probe on the red wire that connects to the battery + post.. I would expect continuity, ergo: the R/R sense the system voltage! (all the time?)

The final red wire (the one you referred to as WIRE ONE) that goes from the upper left pin of the connector into the main harness is the R/R power out wire from the R/R. Within the main harness that power out wire is spliced into the red wire that goes from the MAIN fuse to the ignition switch (described above). That allows the R/R to supply power to the ignition switch (and the vehicle electrical load) and/or a convoluted path back to the battery + post to charge the battery.

To prove this out, break out your ohm meter. Connect one probe to the smaller red wire that connects to the battery + post and the other probe to the power out wire from your white connector. Should always show continuity.

So that's how I figure the PO had the bike wired. No guarantees !
Hopefully it will make it easier for you to go from the current wiring to the one that Nessium reccomends.

And I hope someone will come along and check to see if I maybe I made some wrong assumptions.

 

[SamLack99]

To prove this out, break out your ohm meter and put one probe on the R/B wire (your WIRE TWO) going from the fuse block to the center pin of the white connector and the other probe on the red wire that connects to the battery + post.. I would expect continuity, ergo: the R/R sense the system voltage! (all the time?)

With the ignition switch off = No continuity
With the ignition switch on = Continuity

The final red wire (the one you referred to as WIRE ONE) that goes from the upper left pin of the connector into the main harness is the R/R power out wire from the R/R. Within the main harness that power out wire is spliced into the red wire that goes from the MAIN fuse to the ignition switch (described above). That allows the R/R to supply power to the ignition switch (and the vehicle electrical load) and/or a convoluted path back to the battery + post to charge the battery.

To prove this out, break out your ohm meter. Connect one probe to the smaller red wire that connects to the battery + post and the other probe to the power out wire from your white connector. Should always show continuity.

With the ignition switch off = Continuity
With the ignition switch on = Continuity

Thank you, Jim =)

What I'm concluding from this is:

Red wire (one) will go into the R/R
Red/Black wire (two) is going to be removed.

So...

...The wires for the two connectors that go into the replacement SH775 R/R.

Connector 1 (Grey) will get the three yellow wires from the stator​
Connector 2 (Black) will get the black/yellow wire (four) and Red wire (one)

Now then, do I need to put a 30amp fuse inline on the Red wire (one)?

And if yes, can anyone recommend a simple way to put a 30amp fuse inline on Red Wire (one)?

Thank you =)


​

 

[dgates1]

That should be fused through your main fuse on the block. But like pdqford mentioned, usually larger than 10amp.

Could test by doing continuity on that line again and take out the fuse to see if that breaks it.

 

[pdqford]

Now then, do I need to put a 30amp fuse inline on the Red wire (one)?
;

Well, the factory didn't use an extra fuse in that red wire. It goes up into the harness and is spliced into the red wire that runs from fuse MAIN to the ignition switch.
So power out from the R/R can go two ways. The power can go from the splice up to the ignition switch, and with the ignition switch on the power will come back down the orange wire and feed the top three fuses in the fuse box. And/or the power can go from the splice back to the fuse box, back thru the MAIN fuse and on to the battery.

You can probably remove the fuse box and pop the back off to see what wires go to which fuse, just in case the PO changed anything.

If you decide to add an in-line fuse, 30A is way too big. A short would probably melt some wires before the fuse blows. Again, the factory used a 15A fuse in the MAIN fuse. I don't know but I suspect the charging system would struggle to put out 15A.

Hopefully one of the electrical guys like Nessism or David will come by and verify.

 

[SamLack99]

Ah, I see.

I hadn't understood that the power went through the fuse box (eventually).

So a 15Amp fuse in the Main slot 'should' take care of it.

Got some time off work coming up soon, and I'm looking forward to investing it in putting Suzy back together and seeing if she'll start.

I'll keep you posted =)

Thanks again everyone!

 

[Rich82GS750TZ]

Point of clarification. My pics of a six (actually 8) pin connector are what is connected to the bottom of the fuse box and in no way should they be confused with what Sam had going into his SH555-12 RR. My confusion still lies in Sams pics seem to show no wires in this connector where mine show 2 reds.

 

[SamLack99]

Good point Rich,

Tomorrow, I'll get a picture of the wires going into the connector that goes into my fuse box.

I'd do it now, but it's way past my bedtime =)

 

[pdqford]

Just an FYI, on BikeCliff's website, page 66 of the GS750ET service manual has the wiring diagram for the GS750T(Z).

 

[Rich82GS750TZ]

Here it is…………….

 

[SamLack99]

Here's a video of the wires going into the connector that connects to my fuse box...

I just noticed, I have two cables going into the orange/green slot. Huh?