Topic: '78 cb750k gages on '72 cb750k

[ts354]

Hello all,
I have a 1972 CB750K bike.  I purchased it last year or so and been working on it off and on.  I've been working on the wiring lately.  It had those mini/micro cafe gages on it when I purchased it. (Yuck, don't like them, plus they didn't seem to work that well either)  So I got a set of cheap '78 gages of e-bay.  Here is my question:

The '72 wiring harness uses a single indicator bulb in the gauges.  The '78 gages use left and right indicator bulbs. 
Is there a way / or what would be the best way to wire the '78 gages to the '72 harness and make the left and right indicators work correctly?
Attached is just small portions of the 78 and 72 wiring diagrams.

[newday777]

Show a picture of what you are referring to "indicator bulb" as some references are to turn signal bulbs. The 78 gauges have a separate dash with L&R turn indicator bulbs but not in the 72 speedo and tach in the dash panel which have the single turn bulb.
Is it the turn bulbs you are asking about? Why not get the 7s dash and eliminate the 78 dash then you don't have to fiddle with the wiring?

[newday777]

You can use 1972-76 dash like this

[ts354]

Hmm newday777, you have me thinking.      I have a dash similar to that off a 350 or 450. 

I was also looking, it looks like the 78 uses a three wire blinker relay switch instead of the two wire the 72 uses.   But that won't matter if I use the dash off of the (350 or 450.)

[bryanj]

Either relay will work fine they have nothing to do with what reapeater type you have

[ts354]

You can use 1972-76 dash like this

I looked into that.  I have a cb360 dash light set that I thought could work.  But it doesn't have an Oil Light!  My bike is franken bike.  It has 1979 front forks and triple tree.  Ugg, so nothing but a 79,80,81 dash will bolt up to it - but the tachometer ratio's are not the same for the sohc vs dohc 750's - or are they?

[newday777]

I have no idea about the DOHC.....

[kerryb]

You could make your own custom dash with a panel to hold grommets that fit the led size you buy.  I bought colored Led’s from my local custom radio shop.

[ts354]

You could make your own custom dash with a panel to hold grommets that fit the led size you buy.  I bought colored Led’s from my local custom radio shop.

Nice - that is an option, I have thought about doing that too!!

Is that bracket holding the gages stock or did you make that?
Also who did the gage faces or did those come stock?

[ts354]

So, I could live with both left and right indicator lights on the dash flash when the blinker is on (kind of like flasher in a car).  Would this wiring work?

[ts354]

OR, will it work with this wiring ?

[bryanj]

Second one is better

[ts354]

I went with the second one and it works!

Presenting One CB750k2 (1972) with a cb750f (1978) tank with 1979 front forks with 1978 (k or f unsure) gages/dash!!!!
Oil light not working and the clutch is making a racket when I took it for a test drive, oh boy!!