CB750 Wiring Issues

[royhall]

Here's an example. The output from the flasher relay unit is grey on the diagram, on mine it is light blue with a darker blue fleck but comes out of the harness at the headlight end as grey. WHAT!!!

[McCabe-Thiele (Ted)]

Yep Roy that's why I hate electrics with a passion.

[Oddjob]

But wouldn't the connections for the flasher relay be on the sub loom Roy? In which case the sub loom isn't standard. They are always grey on Hondas for some reason. Sometimes a 3 pin relay and sometimes a 2 pin with no earth connection.

[royhall]

No sub loom on a 750 Ken. Its just three wires bundled out of the main loom. The new loom has light blue, black, & green (unused due to two connection relay). The original harness has the same except light blue is grey. Why it exits the other end as grey heaven only knows, must be connected to something mid loom.

[Oddjob]

No sub loom, never spotted that, but then I avoided working on the 750 whenever possible, didn't like it then, still don't like it. Personal choice, just hated that 1st gear clunk sound, made me wince everytime I heard it.

[royhall]

The only sub looms on a 750 are to the idiot lights and from the alternator.

Sent from my Pixel 7 Pro using Tapatalk

[Martin6]

Mine is a UK bike (K6). It has buzzers on the indicators. Goes for the duration on left turns, only once, then off on right.

I had thought it was a US only thing?

No buzzer on our UK K6 🤔🤔🤔🤔

Yep, that's what I expected. Odd. Definitely, 1st registered in UK. It's a late K6, not registered until 1977.

[royhall]

Am nearly there with the wiring, the stuff in the headlight is an awful mess but once I get the connections right I will tidy it up and remove the bulk where required one cable at a time. My next question is, on a K5 (being a USA only model) does the headlight stay on dipped beam whenever the ignition is on. The back light operates okay on and off with the right handlebar switch but the headlight stays on whatever. It does correctly switch to high beam with the left handlebar switch though. Is this correct. Cheers.

[Bryanj]

If its lights on wiring the rear light should be on as well. Also when you press the starter the headlamp should go off.
I do not know when, or with which model the change occured but i do know that both aftermarket looms and switches cause havok with different wire colours to Honda.
Long distance wiring problems are a real bitch to sort out but if you have a multimeter and can follow instructions i will try and help you out.

[royhall]

Thanks Bryan. It's getting a live from somewhere to the dipped beam and I cannot figure out where. Your right about the wrong wire colours I have spent the last 2 days belling everything through. All appears okay except for the headlight. Am just going out now so will resume the hunt tomorrow if your online.

[Bryanj]

I am away for a week from tomorrow, may be able to read andreplt, depends on black holes, as i said i will try and help but we need to start from scratch mate

[royhall]

Already spent 2 days belling every wire through and labelling them. Everything is right except for the low beam issue (white wire from dip switch) appears to be picking up a live from somewhere. I will find it eventually.

[Nurse Julie]

As it is a late USA model, are the running lights not in the indicators  Roy ?

[Oddjob]

The wiring diagram on post 1 makes no sense. Headlight switch, why a neutral? it's either high or low as a rule plus the connection diagram is wrong, brown would connect to white when on low, not white to blue and in neutral it seems that both high and low are lit? is neutral side lights? if so surely they'd be on the right hand switch?

Check the wires coming out of that switch Roy, when it's on low check which wire has 12v besides the brown, that's the low beam wire. Make sure that's the one going to the bulb as it sounds like you've plugged the wrong one in.

[royhall]

I think it's more complicated than that, I just discovered the headlight is not running through the fuse box. The big problem yet again is garbage pattern parts, both the loom and the switches contain wrong colour cables. Surely if your going to all the trouble of replicating these things you would use the right colour cables. How hard could that be. Maybe it's to stop Honda issuing legal proceedings for stealing their designs. Makes a simple job bloody difficult. Your right Ken, on low according to the diagram there would be no headlight at all. Am going to start again on the lights.

Sent from my Pixel 7 Pro using Tapatalk