[Logan000111]

I’m putting aftermarket controls on on my 75 cb and having trouble mixing new with old. Wiring is definitely not my strong suit and would appreciate the help

 

[TrialsRider]

No doubt. I just looked at the wiring diagram, most of the regulated power (3-phase alternator) goes to your battery and an additional single coil is dedicated to the incandescent lights. (& horn)

 

[TrialsRider]

Keep the horn and any incandescent lamps on the lighting coil circuit, then run all of your fancy low power consumption lights and devices directly off the 12 volt lead acid battery. Your original battery charging system output is not suited to solid state battery, it would need the power better regulated, lead acid will be fine. The battery feeds the engine for spark and the starter motor now.

 

[Logan000111]

I’m honestly just trying to figure out what wires are for what on the left side of the handlebars. No matter how many times I look at the diagram and put everything where it’s supposed to go I blow a fuse its either the main, front light or both

 

[TrialsRider]

rule of thumb is that switches usually make a ground connection, not a hot connection, hot switch connection are usually controlled through solenoids or solid state.
All of the lighting wires run off a separate coil and rectifier/regulator from the great big 3 phase alternator used to charge the battery and spark the plugs, you have a battery coil ignition. The only thing you can run on that lighting circuit is the stock lights. If you are blowing fuses on that system and running stock, then check your horn, that is one of the highest draws after the headlight and prone to age failure in a high current draw kind of way. Just disconnect it (the horn) and see if that helps

 

[TrialsRider]

what are "aftermarket controls" that made connections complicated? is that like voice activated that would be cool

 

[Logan000111]

They are just cheap handlebar controls, for the kill switch, indicators and everything

 

[Logan000111]

I just put budget ones in for the moment to get me through summer then this winter I was going to upgrade

 

[TrialsRider]

Engine stop switch is special
that might be messing you up

 

[Logan000111]

Yes, I got the right side controls done and they work fine but the indicators for the left control I cant get to work I’ve looked at both diagrams and took it apart to see what wires go to what nothing helps. haha might have taken a bigger bite than I can chew

 

[TrialsRider]

... I’ve looked at both diagrams ...

I'm looking at the wiring schematic diagram for a 1975 CB750, what's the second diagram to make a both? Did the aftermarket switch set come with its own wiring diagram, if yes then I need to see it.

Fuses blow because you are drawing too much power, such as a short in the wiring. In the case of the CB750, consider it to have 2 separate power systems, you need to keep that kill switch circuit isolated from the lighting circuit. They can't share a common ground at the handlebars and you have a slew of ground wires because everything is rubber mounted, or at least it was unless you changed lights or added something that draws additional power on the lighting circuit.

 

[TrialsRider]

Photo of the motorcycle might help, we're running blind here

... and the screen grab you posted above doesn't look anything like the wiring diagram I've been looking at.

 

[TrialsRider]

 

[TrialsRider]

Here's a detailed schematic for just the "Starter Motor Safety Unit"

... which looks a little weird because there appears to be 7 wires coming out of the unit pictured here and not 5

 

[TrialsRider]

That safety unit is shown to contain: 3 diodes, 1 lamp, 2 resistors and 2 bipolar junction transistors.
Lots of goodies to burn out in there.

I found the diagram you are working from, that's for the K4 which is a 1974 model

 

[TrialsRider]

I'll let you in on a little secret; the best electrics that you can possibly have on your old bone motorcycle is the electrics that came on it.

 

[CaTacL1sm]

I'll let you in on a little secret; the best electrics that you can possibly have on your old bone motorcycle is the electrics that came on it.

generally

 

[Classic250]

I'll let you in on a little secret; the best electrics that you can possibly have on your old bone motorcycle is the electrics that came on it.

Probably true with Japanese motorcycles - but all my Ducatis had pretty bad electrics.