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Discussion Starter · #1 ·
Hello, new member here, happy to find this community!

I am bringing this CB350 back to running order after 44 years off the road, 2350 miles on the odo. Bike is actually in great shape, was properly stored. Have addressed the carbs, cam chain and valve adjustments. Now onto new points, condensers and what ever else is needed on the electrical side. This is where I am having an issue.

This bike had an aftermarket driving light installed, with some odd coil unit, along with a voltmeter. I don't intend to keep these two pieces and I need to return the wiring harness to original configuration. With a known good battery I have no power anywhere in the harness. I suspect this is due to the wiring modifications made back in the 70s, but can't be sure. Here are the wiring modifications I have flushed out so far.

1. In the condenser wiring area; at the aftermarket coil, the gray/white wires have been attached to this non-stock coil, coil grounded at its frame mount. I have removed this wiring, and joined the two gray/white wires in an effort to reconnect them to the engine stop switch as per the wiring diaphragms. Note, I have my stock 74 CB360 in the garage as a reference, the harnesses are not the same but there is some similarity.

2. At the starter relay; the red and red/white wires have been joined then connected to the hot side of the aftermarket voltmeter. The ground from the voltmeter has ring terminal at its end which appears to have been connected back to the negative side of the battery. I am eliminating the voltmeter, at least for now, but am not sure if I need this ground wire or where I need to connect the red and red/white from the starter relay. Note, I have continuity from the red/white at the starter relay to the red/white at the rectifier.

3. In my troubleshooting, with the battery hooked up, I find no power at the red/white at the rectifier. This bike retains the large orange rectifier behind the battery and the separate regulator. I am tempted to install the newer style regulator/rectifier from my 74, if that would work without cutting up the existing harness, but would like to avoid that if possible. Should I ditch the old regulator and rectifier anyway and start there?

4. I have verified functionality of the ignition switch but have not been able to do the same for the engine stop switch, although I have it apart and it looks unaltered.

So with the battery hooked up I find no power anywhere. I am guessing I need to reconnect the red/white from the starter relay area to the regulator but haven't completed untaped the harness to determine where this wire may have been cut previously. for testing should I just run a temp wire?

Love these old bikes and took this project on for a friend. His father bought the bike new and we are hoping to reacquaint him the running bike when he visits Montana in July.

Any suggestions are greatly appreciated!

Couple photos for reference with notations.

IMG_0969.jpg

wiring at aftermarket coil.jpg
 

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A short battery cable goes from battery positive to the starter solenoid post(hot side) the red/wire from the rectifier and a smaller red are also connected there. That red wire should have a fuse holder in its length, it goes into the main wire harness to supply the ignition switch. If you want to use that voltmeter(it could be handy to have for future use) connect its power wire to one of the black wires in side the headlight.
 

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Sensei
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Josh,
The heavy (~8 gauge) battery positive wire SHOULD go to the SAME solenoid terminal as the red & red/white wires.... Battery negative (also ~8 ga.) to a rear motor mount bolt.....
Once that is corrected, you should have power to the "key" switch, (Assuming the fuse is good).....
Turning the key "on" should put B+ power to ALL the stock black wiring......( Leave "Kill" switch turned to "off")
Once you've checked that far, phone me....too much to type.......
 

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Discussion Starter · #4 ·
Awesome, thanks for the info guys! Will get back at it tonight. Worked on it last night until I couldn't see or concentrate any further, but love the process.
 

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The red/white wire connects to the solenoid in the same place as a red wire. The red wire supplies power to the ignition switch. There is an old school barrel fuse in line of the red wire. These fuses can appear to be good but not conduct electricity. The red wire runs only to the ignition switch. When the ignition is turned to the run position the circuit between the red and black wires are connected and the black wires carry power to all of the electrical circuits on the bike.

I would remove the accessories from the wiring harness by just disassembling and repairing the factory wires as you find them.
 

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Discussion Starter · #6 ·
Progress! I pulled the starter relay from my 74 with its red and red/white wire intact, installed it on the project bike and bam, neutral light came on!

The aftermarket voltmeter was formerly attached to the red wire at the starter relay, so once returned to stock it is working. Not sure why someone cut into the gray/white at the condensers but I had to clean that up as well. So with power to the harness I checked and found spark at both plugs. It was late but I went ahead and reinstalled the carbs, rigged up a way to feed fuel (original tank is terribly dirty), and with a bit of fiddling the bike that hasn't ran since '75 fired up! So excited, sent a video to the owner, high fives all around!

This bike has an automotive driving light installed on the front crash bar, along with some aftermarket coil that I mentioned above. I thought I had removed all the wiring for it when repairing the harness, that coil is disconnected, but much to my surprise the old driving light came on when I fired up the bike. It was just one of those evenings when everything comes together. Not sure what purpose the aftermarket coil serves. I was guessing it was for the extra light in some way but not so.

Plan to replace the points and condensers tonight and start cleaning the fuel tank with muriatic acid.

Thanks again for the help gentleman. Hopefully I can get a short video of the original owner seeing the bike run again, will follow up!
 
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