Help identifying some rogue wires

[RJordan09]

Hello all,

I am currently cleaning up the wiring on my 1977 GS750. Everything is going fairly well, but I have some wire's that have no home at the moment, hoping you can help:

Starting with this picture first, I recognized the white & orange for the brake light switch, which leaves me with 1 random brown wire. It is not the brown wire in the engine start / kill switch:



I think the next two pictures are for hook-ups to a fuse box, but I am seeing NO evidence that this bike ever had one - no spare parts hanging around, no mounting holes in the battery box, so I'm not sure.






I've seen that the partsoutlaw diagram for "electrical" shows a fuse box but I only have 1 fuse in a hard plastic cover on the positive wire heading up to the battery. Any thoughts?

Thanks as always!

[Nessism]

Basscliff's website has a factory service manual for your bike. Inside you will find a wiring diagram. The wiring diagram shows the brown wire gets power from the ignition switch and then runs back to the tail light, and it also feeds an accessory bullet connector that should be up in the headlamp shell.

In looking at the wiring diagram for the early 750 there doesn't appear to be a fuse box.

[RJordan09]

I must be looking at the wrong diagram....I am looking at GS750 (16-valve) Color Wiring Diagram

[RJordan09]

Ahhhh, the diagram in the service manual...got it. Wow, this is much better

[RJordan09]

So is it really a connector to no where...?

[RJordan09]

OK, so I have this mostly figured out with the exception one 1 red wire. It routes from the points cover along with a black wire and a white wire. For the life of me I can't find where the red hooks into the harness. It seems to be ignition related though, for the most part everything else is responding when I put the battery in aside from the ignition switch.

Thanks!

[allojohn]

OK, so I have this mostly figured out with the exception one 1 red wire. It routes from the points cover along with a black wire and a white wire. For the life of me I can't find where the red hooks into the harness. It seems to be ignition related though, for the most part everything else is responding when I put the battery in aside from the ignition switch.

Thanks!

As you can see from the wiring diagram there should be no red coming from the points, so that's pretty interesting. And yes, there's no fuse box on the '77-'79 750's just single fuse! But, you know it would be a good idea to add one and do the relay upgrades for ignition, coils and headlight at a minimum.

[RJordan09]

As you can see from the wiring diagram there should be no red coming from the points, so that's pretty interesting. And yes, there's no fuse box on the '77-'79 750's just single fuse! But, you know it would be a good idea to add one and do the relay upgrades for ignition, coils and headlight at a minimum.

For now I'm just trying to validate the current system, then I'll look at upgrades . The "red" wire in question is a bit more on the orange/pink side than the red that runs through from the ignition switch. It definitely seems to be the key to getting the start button to come to life..


It's the wire in the last picture on the post above. You can see it routing in the sleeve with the white wire and black wire.

[Steve]

But, you know it would be a good idea to add one and do the relay upgrades for ignition, coils and headlight at a minimum.

Before going through a lot of effort and butchering various parts of the wiring harness, do a few simple checks to see if you have voltage drops to the various circuits. The concept is further muddied up a bit on this bike because there is only one fuse.

If you do have low voltage getting to the various accessories, check the voltage after the ignition key and compare that to battery voltage and the voltage at the accessories. It's quite possible that ONE relay that powers the whole bike will do the job and will be easier, quicker and cheaper to do.

.

[sam000lee]

I have that same 4-pin connector on my '77 GS750 that doesn't hook up to anything.

[posplayr]

I hope you are spraying Deoxit into your connectors and especially those horrendous but connectors!

[allojohn]

It's the wire in the last picture on the post above. You can see it routing in the sleeve with the white wire and black wire.

Open up the points cover and see what the red is connected to...if anything.

[RJordan09]

Hmmm....

[allojohn]

Hmm indeed, looks fairly legit. Someone on here will know what it is......

[chuck hahn]

I think the red is the hot wire that gets spliced to one of the hot wires that feed the coils. It supplies power for the electrinoc ignition to signal the colis to fire. Doesnt look like a Dyna ignition but it does look like the same wire set up I have found on the Dyna kits.