Topic: New key shorted out bike?!

[epheme]

I bought a CB550 yesterday. Came with the wrong key so I jumpered it to make sure lights turned on, etc. Got it running.
All lights and bulbs seemed to work great! 

On my way home I stopped and got the correct #key, tested it in the ignition to make sure it would turn.

Plugged it in, turned to ignition. Gauges lit up as expected.
Cranked it once and it turned over then went completely dead. I didn't hear it short but I'm assuming that's what happened since I no longer get spark where I did yesterday when jumpering. Figured maybe I just blew a fuse.

Unfortunately when I inspected the fuse box the prior owner had put a piece of copper tubing where the 15A fuse should have been, and I didn't catch it.

I have the wiring diagram, but I'm at a loss as to where to start. Work back from the ignition switch or forward from the better, or elsewhere. Common failure points?

[bryanj]

There are no common failures on the 500/550 but after 40 years anything can fail. Just getting the correct ket will not have shorted it. Check for 12v between red wires and ground then with key on black wires and ground for a start

[epheme]

Thanks. I went to ohm out the switch and pulled two ?? Snails? Insect larvae?? ...out of the drainage hole. Knowing that there could have been a short in my ignition switch, I suppose that still doesnt narrow it down.

While I was checking connectivity, I found two disconnected areas: a green spade connector behind the battery, and a black and white pair of wires underneath the gas tank. I'm going to try to find them in the wiring diagram, but any info is helpful.

[robvangulik]

With a piece of copper in place of the fuse it should have smoked at any short, follow your nose?

[rotortiller]

That is one filthy bike. It does not surprise me you are having problems. First thing I'd do is wash it and evaluate the wiring and connectors.

[Dolomite]

Black and white under the tank should be the coils.

[robvangulik]

Black and white under the tank should be the coils.

Nope, that's black with a white stripe.

[epheme]

I fixed it! It was the crummy fuse box.

I did wash down the whole bike, and removed and gently cleaned the electrical panel. I suspected the fuses since PO had done some shenanigans with the copper tube for a 15A fuse.

I looked at the parts bike and it also has the green spade connector loose in the electrical panel.

The lonely wires under the tank may go to a horn. My bike currently does not have one. It is black and very light green, not white.

Reinstalled with correct fuses and reinstalled the carbs I cleaned last night....

https://www.instagram.com/p/Byk9SpeFmAJ/?igshid=166xc9mse50m3

[Don R]

 The extra green is ground for a three wire blinker. They usually have two wire ones. There may be an extra wire or two in the headlight bucket which is normal. Bikes sent to other countries have the same harness but a park lamp in the headlight.

[cshanek]

I have had this happen due to a short in the actual right handlebar switch where the soldered set of wires was making contact with the bar. Killed my fuse.

I bought a CB550 yesterday. Came with the wrong key so I jumpered it to make sure lights turned on, etc. Got it running.
All lights and bulbs seemed to work great! 

On my way home I stopped and got the correct #key, tested it in the ignition to make sure it would turn.

Plugged it in, turned to ignition. Gauges lit up as expected.
Cranked it once and it turned over then went completely dead. I didn't hear it short but I'm assuming that's what happened since I no longer get spark where I did yesterday when jumpering. Figured maybe I just blew a fuse.

Unfortunately when I inspected the fuse box the prior owner had put a piece of copper tubing where the 15A fuse should have been, and I didn't catch it.

I have the wiring diagram, but I'm at a loss as to where to start. Work back from the ignition switch or forward from the better, or elsewhere. Common failure points?

[epheme]

Thank you! I sprayed a bunch of contact cleaner in there and tried to get it working and feeling good, but I'll clean that up soon.

[Airborne 82nd]

Black and white under the tank should be the coils.

You sure about that? Shouldn't it be black with a white tracer? From kill to coils.
@ epheme It would serve you well to read all the FAQ & tips and tricks here is just one item.
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)

**NOTE- I pieced this together from referring to wiring diagrams I have. This is meant as a general guide and will vary between models/years. If anyone spots an error or omission, please post it and I will correct it. Thanks**

[epheme]

I may have been unclear. It is a solid black wire, and a solid, light green wire. the only light green wire in the diagram goes between the horn and the horn switch.

[Don R]

   Yes horn, a simple test lamp made from an old taillight or dash light can work wonders.