Wiring question related to a 1981 CB750c

[ezridermn]

Hi. As part of my Cafe project I removed a Vetter Fairing (with turn signals and headlight built in) from my 81 CB750c. I am now in the process of installing a regular headlight on the fork tubes. I believe I have most all the wiring connections re-established as they were originally designed.

However, there are two wires in the headlight area that I have been unable to identify where and what they should connect too. One is a brown wire that appears (per wiring diagram) to run back to the rear brake light and turn signals. The other is a black wire that I am not sure where it goes.

I have a Clymer color wiring diagram I have been working with. (see attached) It shows a brown wire (red oval) that terminates near the front of the bike with no connection to anything else. What does it mean when a wiring diagram shows a wire with no connection to anything?

The black wire is a bit more confusing because the only black wires on the wiring diagram are related to ignition and starter related connections. However, the ignition and starter seem to be working just fine even though there is this unconnected black wire in the headlight area.

In addition, the instrument lights, headlight and turn signals seem to be functioning correctly as well.

I am thinking maybe these open connections have something to do with the Vetter fairing installation and are not needed for a relatively stock headlight implementation. But then again...

I would really appreciate if you would take the time to help me better understand what the wiring diagram means, what the wires are for and what I should do with them.

Thanks in advance for your help!
Bob

 

[crazypj]

On Honda's, black is live after ignition switch and brown is side/pilot/parking light.
They are probably spare for a different market which has similar but not same electrical system

 

[jay_kent]

As stated above by Mr. Pj. The same wiring harness was used on multiple bikes. your harness is similar to my 79 cb650. Those wires do nothing. Probably noticed that you have 2 green ground as well?

 

[bikeboy]

The same wiring harness was used on multiple bikes.

yep. the brown is for the euro/oz parking light bulb fitted inside the headlight reflector. The black I'm not so sure about, but like the guys say, it will be a spare. Test it with your favourite test-tool, you'll find the black is live with ignition. The brown will be live when your lights are on (are they switched?). Just make sure they can't short anywhere.

cheers
ian

 

[ezridermn]

Hi Guys,


Thank you all very much for the info. It is exactly what I needed to know. Now it is into the shop to finish up my wiring job!



Bob