Topic: 1975 CB550K wiring issue? Common ground?

[shameless550k]

1975 CB 550K
So, tracing down a faulty ground in the headlight bucket, led me to pulling a dangling ground out of the main wire wrap on the left hand side of the bike. This led to unwrapping and discovering three busted pairs of green wires and a pair of split black wires. The greens should be ground wires, and should be safe to solder together. The black pairs should be the same, right?

I bought this bike from the son of the original owner, so I'm thinking that this 'fix' was at least 20 years old.

Is there a better option for fixing these wires?
Would I be better off terminating all the grounds in the bucket to a single terminal, and bolting it to the frame?
Is there a specific reason that Honda has all these parallel ground wires instead of a single thick gauge cable?

[Danno]

the wires are separate for a reason if you loose one ground to a specific object say the turn signals you don't loose the tail lights and other items technically yes you could solder them together but what is the point of having separate fuses if you did some older bikes only had one fuse for this reason

my advice is replace the individual grounds and keep the wiring harness the way it was intended  unless of course you just intend to replace the ground wire every time it goes bad because that will be your only choice if you have a ground problem

honda changed to this system for a reason it is much easier to track down a ground fault if you know which system is affected with only one ground wire they would all be affected where do you start looking then ?

motorcycles in general have troubles with grounds from rust and vibration

[shameless550k]

Can I solder these two black wires to their counterparts coming from the bucket, and shrink wrap the whole mess?

[bollingball]

Shameless  NO NO Black is NOT ground on these bikes only green. They are not the same Do not tie them together.

 Quote from Shameless: The greens should be ground wires, and should be safe to solder together. The black pairs should be the same, right?

 Red is 12v from the batt. it goes to the key Sw. when key is on the red g
changes to black and feeds several things. You will find a lot of these black connecttor in the headlight bucket.
There is a thread I think it is in FAQ that is a good guide for what each color of wire on the bike is for. I will see if I can find it.

                                         Ken 

[bollingball]

Found it in FAQ under electrical

More from Jonesy:

(I put this together after a few questions about the wiring in these bikes. Some suggested this be put in the FAQ. Hope this is helpful.)

Here’s a general wire guide for the 70’s Honda SOHC/4’s. Some of this may be different for the 650 (I’m mostly familiar with the 350, 400, 500/550 and 750) or bikes factory-equipped with electronic ignition. Consult your manual for specifics.

Main Color/Tracer Stripe Color- Description (Approximate Path, if Applicable)

All Circuits
Red- Constant Hot From Battery (Battery Terminal-Main Fuse-Key Switch)
Black- Switched Power Supply Buss (Throughout motorcycle)
Green- Ground (Throughout motorcycle)

Lighting
Brown- Tail Light Power (Main Switch-Tail Light)
Brown/White- Instrumentation Backlighting (Lighting Switch-Instruments)
Orange- Left Turn Signals (Turn Signal Switch-Front/Rear Signals)
Orange/White- Left Front Marker (Light Switch-Marker Lamp)
Light Blue- Right Turn Signals (Turn Signal Switch-Front/Rear Signals)
Light Blue/White- Right Front Marker (Light Switch-Marker Lamp)
Gray- Pulsing Power for Signals (Flasher Relay-Turn Signal Switch)
Blue- High Beam Power (Hi/Lo Switch-Headlamp/Indicator Lamp)
White- Low Beam Power (Hi/Lo Switch-Headlamp)
Brown/Red- Fused Headlamp Power (Fuse Box-Hi/Lo Switch)

Ignition
Black/White- Coil Power Supply (Cutoff Switch-Coils)
Yellow- Breaker Signal, Cylinders 2&3 (Right Points-2&3 Coil)
Blue- Breaker Signal, Cylinders 1&4 (Left Points-1&4 Coil)

Starting/Safety/Monitoring
Blue/Red- Oil Pressure Signal (Oil Pressure Switch-Indicator Lamp)
Red/Green- Neutral Switch Signal (Neutral Switch-Indicator Lamp-Safety Unit)
Green/Red- Clutch Switch (Safety Unit-Clutch Switch-Starter Button)
Green/White- Horn (Horn Button-Horn)
Yellow/Red- Solenoid Signal (Starter Button-Solenoid/Safety Unit)
Green/Yellow- Brake Light Power (Front Brake Switch/Rear Brake Switch-Brake Light)
Brown/Blue- Turn Signal Pickup (Turn Signal Beeper-Turn Signal Switch)

Charging (3-Phase External Excitation Systems)
Yellow- Stator Coil Output (Stator-Rectifier)
White- Field Coil Supply (Field Coil-Voltage Regulator)
Red/White- Positive Rectifier Output (Rectifier-Battery)

[bollingball]

One more thing. It is common to find a green wire not used under the tank on the left side and under the left side cover close to the turn signal flasher. These wire harnesses were used in other country's and these grounds were used over there. Also you may find a unused brown wire in the bucket it was used for a little parking light over seas that we don't have.

                                              Ken

[shameless550k]

Thanks Ken.

I was going to solder the black to black, not black to green, and solder the green to green.
I appreciate the comprehensive wire guide.

I'll solder and terminate the grounds as soon as I finish this beer, and then solder the switch wires together. Separate but equal. Hopefully that will fix the ground issues.

[bollingball]

Beer makes me forget to slide on the shrink tube before I solder the wires 

                                        Ken

[shameless550k]

So...soldered the ground together, and the blinkers responded well.
Tried soldering the black wires together and no dice.

Somewhere I lost the headlight hi/lo switch. Those two black wires weren't connected before, and the switch did work.

The HID conversion makes the lowbeam super bright, but I want the highbeam as an option.

Should be good enough to pass inspection, but how do I need to but these wires together?

[Spanner 1]

You may have high and low beam on together 

[shameless550k]

light pattern matches the low beam, but ive got no idea how the PO had it wired up to work.

[nwrocker]

The two black wires should go to different things.  On the CB750 there are  independent black wires that go to the high beam warning light, neutral warning light, turn signal buzzer, handlebar control switches, horn, starter solenoid and front stop switch.  Separate wires running together like that would go to different things.

[bollingball]

Shameless Just ran across your post again. Where are you stuck at now ? Just the high beam not working?

                                       Ken

[nwrocker]

Black wires are switched hot wires.

[shameless550k]

Quick update.

Yesterday went into the bucket again, troubleshooting the headlight, hi lo issues.
Seems the late original owner, or his son, the PO had modified the stock harness and a few of the wiring issues may have sprung from that.

After looking at the wiring diagram (thanks SOHC4) and plugging and playing with wires and switches I have
: Both sets of turn signals working
: Brake light working off foot or hand brake
: Low beam and running lights

So, progress. I still have a few disconnected black switched wires. One was to the turn signal buzzer, which is annoying enough to pull and be fine without. The other one belongs to points unknown.

While in the bucket, with low beam and running lights on, I 'adjusted' something, heard a pop, and now all electrics are gone. I've changed out the three fuses in the fusebox and the 10 amp HID headlight fuse. No dice.

Could that be a shorted ground somewhere else?
Two steps forward, one step back.

[shameless550k]

Update on Bike.

With the ignition on, and headlight switch off, both front and rear turn signals work. The brake light doesn't work.
With the ignition in the park position, the brake light works with the foot pedal.

With the headlight switch on, the turn signals still work, but no headlight.

The high beam and low beam have worked with the HID light. After dismantling the PO's wiring harness fix, the high beam low beam selector switch doesn't affect the light.
I've replaced all fuses, but there still no dice.

I've been using the color 75 550k wiring diagram to run my traces, but I haven't had any luck.

I'm trying to get this to past inspection. If I can get just the low beam working.