Author Topic: 1978 750K ignition wiring issue  (Read 966 times)

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Offline rassmuss

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1978 750K ignition wiring issue
« on: May 05, 2016, 12:58:52 AM »
Hi, new member here .....  I recently acquired a fairly nice 1978 CB750K, however the previous owner lost the ignition key and cut the wiring at the switch in an attempt to hot wire it.  I purchased a new switch and I am a little confused as to which wire goes to each terminal.  There are 5 wires:  1 red, 1 black, 2 brown and one striped brown wire.  I attached pictures to this post and named each terminal, could someone direct me as to which wire goes where?  Thanks!


Offline calj737

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Re: 1978 750K ignition wiring issue
« Reply #1 on: May 05, 2016, 12:46:07 PM »
It's difficult to know (for me) exactly which pin does what, but, with a key and a meter, you can easily verify. The RED wire comes from your fuse block as the MAIN power. Once the key is switched ON, the BLACK wire carries power to many of your bike's functions, and the meter would show continuity between the 2 spades (RED and BLACK). The problem is, the other 3 spades (BRWN, BRWN, and BR/WHT) will also. The 2 BRWNS get jumped together according to the attached wiring diagram:
http://manuals.sohc4.net/cb750k/technical_reference/WD750K8.jpg

Once you put new spade ends on the wires, its not difficult to swap a few around to determine which ones should have a particular color on them. You could also trace back down your loom and look at the nearest plastic connector to identify the orientation.

I don't know if any of this gets you closer, and perhaps someone with a K8 will chime in with exact pinouts, but its pretty simple to diagnose on your end if you have a few minutes.
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Offline madmtnmotors

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Re: 1978 750K ignition wiring issue
« Reply #2 on: May 05, 2016, 02:15:08 PM »
I can probably check the connector on a harness here and sort the pinout for you. Might not be tonight though!
TAMTF...


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Offline rassmuss

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Re: 1978 750K ignition wiring issue
« Reply #3 on: May 05, 2016, 03:20:12 PM »
If you could, that would be a solution to my issue.  Thanks for the reply!