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Discussion Starter · #1 ·
On a 72 CB350K4 I need help sorting out the correct wiring connections in the bucket. I'm a complete novice with this wiring.

The bike came with ape hangars, and both the RH and LH control switch harnesses were extended into the bucket with a few inches of red wire. Everything worked except the engine cutoff switch on the RH control. Bought new standard bars and replaced the RH control switch with NOS. Then after connecting the like color wires in the headlight bucket: the headlight, taillight, and turn signals work, but rear brake light stays on as if the pedal is depressed (which it is not). Starter and horn do not work, but both have continuity. I should mention that there was/is one female brown connector in the bucket that wasn't wired to anything. Except for the red extenders, nothing else was spliced and the wiring appears to be original.

There are two solid black and one B/W wire coming out of the RH control harness. There is a four-way connector with a B/W wire in. The problem may just be that I have something connected wrong. I have a wiring diagram but I don't understand the logic. Any help is appreciated.

I can send pics but sorry to say I need help trying to attach them.

John

Electrical wiring Auto part Wire Cable management Electrical supply
 

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If the wiring is all OEM then it is just a matter of connecting like colors.

The Rear Brake pedal Switch is adjustable for the point at which it makes contact.

Also double check you Front Brake Lever Switch.
either one will turn on the rear brake light.
 

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Discussion Starter · #3 · (Edited)
If the wiring is all OEM then it is just a matter of connecting like colors.

The Rear Brake pedal Switch is adjustable for the point at which it makes contact.

Also double check you Front Brake Lever Switch.
either one will turn on the rear brake light.
Didn't know whether to continue this thread or start a new one, but just got the bike running last week. Until now, all the wiring issues were addressed with the engine not running, so I thought the wiring was sorted. Today I noticed the tail light bulb was out (brake light filament still worked). With new bulb installed, bike running, and head light switch off, the tail light would light, brightening as I revved the engine. All the other lighting worked properly. Turning on the headlight returned everything to normal, including working blinkers. Thinking it was a grounding issue, I checked the tail light connections and looked for shorts under the fender and anywhere else with exposed wiring (outside the main loom). Found one interesting connection between the gas tank and the head light bucket. On an exposed area of the main loom, three black wires coming from the rear were soldered to one black wire going forward. I don't think it was factory.

Checked connections in the head light bucket. There was one brown wire coming from the main loom not connected to anything. I could not find another brown wire to connect to. All the others seemed to be connected like color to color. Tried undoing and reconnecting some of the connections, but may have changed something. Now the tail light issue is gone, but I have no blinkers and no gauge lights, engine running or not. I have a wiring diagram, but I still don't fully understand it. I want to explore every avenue before going to my mechanic. Thanks in advance. John
 

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I have attached the CB 350 wiring diagrahm.

Do a Right CLICK and OPEN in a New TAB.
You will be able to enlarge it for better visability.
Also I recommend Right Clicking and SAVE-AS to a USB then having it printed by a Staples or Fed-Ex business center on a large format printer.
It makes tracing the wiring really easy to have it in large format.

Plan Floor plan Text Diagram Technical drawing
 

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I have attached the CB 350 wiring diagrahm.

Do a Right CLICK and OPEN in a New TAB.
You will be able to enlarge it for better visability.
Also I recommend Right Clicking and SAVE-AS to a USB then having it printed by a Staples or Fed-Ex business center on a large format printer.
It makes tracing the wiring really easy to have it in large format.

View attachment 273134
Great advice. I have mine printed off on four 8.5X11 sheets and pinned to the garage wall. Its great having it in large format and readily available at anytime to verify some wiring. I do that with any bike I'm working on.
 

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Discussion Starter · #7 · (Edited)
I checked the voltage last week when I got the bike home. It read 12.8 at idle, 13.7(?) at 2k. I have a wiring diagram, printed and enlarged from original post over a year ago.

Looking at this one, it looks like the solid brown comes from the tail light to the ignition switch, TL2. Then the br/wh goes from the ignition switch TL1 to the gauge lights. There is a female solid brown and a male br/wh coming out of the main loom in the headlight bucket. Does the solid brown connect to one of the br/white wires?
 

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What a rat's nest in those buckets........all I do is connect and hope and pray all goes well.
 

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Discussion Starter · #9 ·
Following pics show current connections in bucket. The female solid brown from the main loom is connected to the br/wh going up to RH handlebar switch. The br/wh from main loom is connected to the gauge br/wh's.
The orange from main loom connects to orange going to left blinker, left handlebar switch, and blinker bulb. The blue from main loom goes to blue going to left handlebar switch, right blinker, and blinker bulb. Everything except blinkers work; they don't light at all. Maybe flasher?
 

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Discussion Starter · #10 ·
What a rat's nest in those buckets........all I do is connect and hope and pray all goes well.
I agree, 40+ years of "I wonder where this goes?". Does anyone have a picture of the bucket from the factory, untouched by human error?
 

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Discussion Starter · #11 ·
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Following pics show current connections in bucket. The female solid brown from the main loom is connected to the br/wh going up to RH handlebar switch. The br/wh from main loom is connected to the gauge br/wh's.
The orange from main loom connects to orange going to left blinker, left handlebar switch, and blinker bulb. The blue from main loom goes to blue going to left handlebar switch, right blinker, and blinker bulb. Everything except blinkers work; they don't light at all. Maybe flasher?
 

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I do have a 350/4 that's never been touched, but I didn't take pix of it when I had it open.

But since I put it back together, I'm leery to open it back up.
 

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Discussion Starter · #13 ·
Following pics show current connections in bucket. The female solid brown from the main loom is connected to the br/wh going up to RH handlebar switch. The br/wh from main loom is connected to the gauge br/wh's.
The orange from main loom connects to orange going to left blinker, left handlebar switch, and blinker bulb. The blue from main loom goes to blue going to left handlebar switch, right blinker, and blinker bulb. Everything except blinkers work; they don't light at all. Maybe flasher?
Pics here
 

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Discussion Starter · #14 ·
I don't like opening mine unless I have to.
 

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Discussion Starter · #15 ·
Sorry for the duplicate pics
 

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Actually, you'd never get a picture of the wiring in the headlight bucket from the factory - that's because the headlight, handlebars, turn signals and gauges didn't come on the bike from the factory. As delivered in the crate from Honda, the handlebars, turn signals, headlight assembly (sealed beam/bulb, ring and bucket) and gauges were packed in separate padded bags in boxes and included in the crate with the bike which was mostly assembled. The front forks and headlight ears were assembled in the upper and lower triple clamps with the lower halves of the handlebar mounts already in the upper triple. The front fender was packed separately as was the front wheel, often with the axle in a bag of separate hardware as well. The front wheel had to be put together (axle in along with speedo drive on some models, put in the proper direction) and the bike lifted to put the front wheel under the forks after the front fender was installed, then the headlight bucket, turn signals and handlebars all installed, then the wires from all of them, including the main harness, routed into the bucket, then all connected as per proper colors, then the headlight assembly installed to close everything up after filling the battery with electrolyte, installing it and testing all the functions to be sure all the wiring was correct... oh, and the seat and passenger pegs and often the front pegs as well had to be installed too. Then oil and gas and fire it up for the first time... all for $2 to $3 per bike back in 1970. I did many hundreds of them... so no, if you ever got a picture of the wiring after it was all put together, it wouldn't have been as it was from the factory
 

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Discussion Starter · #17 ·
I'm wondering how long it took to "assemble" one CB350K?
 

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If you mean out of the crate, after you got good at doing them - being a 15 year old and just into bikes the year before, it took me a few to get proficient at it - you could do one in an hour or so, maybe less IIRC... but that was almost 50 years ago. It was one of the most fun jobs I ever had at the Honda dealers, and it taught me a lifetime of knowledge of Honda wiring colors that are mostly in use across all of our vintage bikes
 

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Discussion Starter · #19 ·
Then could I ask for your comments about my blinker/wiring issue.
 

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It really is as easy as matching colors.

There will be a leftover Brown Wire inside the headlight bucket that was used for Overseas version that required front Marker lights in the turn signals.
Dual filiment sockets in the front like the 360 has.
 
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