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Discussion Starter · #1 ·
The tail light is not working on my 1968 CB350 in the first key position. It does work in the second position.

The tail light is powered by the brown/white wire coming from the handlebar switch which connects to the brown tail light wire coming from the ignition switch when the key is in the first position. Using a multimeter I found that I have 12+ volts in the brown/white wire in the headlight bucket when the the lights are switched on. Also, the instrument lights, in the tach and speedo work, which are also powered by the brown/white wire coming from the handlebar switch.

Since I have power in the brown/white wire which goes to the ignition switch and a good circuit in the brown wire that goes from the ignition switch to the tail light, I assume the ignition switch is not connecting the brown/white wire to the brown wire when in the first key position.

Is there a way to disassemble the ignition switch to repair it? Are there any other ideas on why the tail light does not work in the first position? Again, the light works in the second position when the ignition switch connects the red battery wire to the brown wire to provide a parking light.

I currently have the brake light green/yellow wire disconnected but I don't know that would make a difference.
 

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Spin assume you checked the brown wire for power first?
Before disassembling the ig switch, use a multimeter to test continuity between the connectors when in various positions.
You have the stock handlebar pod installed?
Your tail light socket and bulb are in good shape, and ground wire is connected?
 

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Discussion Starter · #3 ·
The brown wire gets power in the second key position but not the first. Tail light bulb illuminates in the second key position so ground wire, bulb, and socket are in good condition.
 

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You can disassemble the switch and clean the contacts on the back of where the wires are soldered on. They do tend to get corroded inside if they sit inactive for a long time.. which sounds like at least half of these bikes we're working on :D there are little "tabs" of switch body metal (so to speak) that are bent inward over the bakelite back of the switch, bend them open and the back comes off
 

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The park wiring isn't the same as ig on. Is your bar pod installed. It connects black with brown white

Edit: before disassembly you should confirm continuity at the plug end
 

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Pretty sure that you've got the problem figured out, when the ignition switch is in the first position, power should flow from headlight switch input to tail light output. The switch can be disassembled and the contacts cleaned, but it can be a fussy job. You could by pass the switch, but you'd lose the parking light feature.

......Paul
 

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Make sure all the pins are making good contact with their sockets in the round plug that connects the switch wiring to the harness. If that doesn't solve it, before taking the switch apart, I'd try spraying some WD40 into the key hole and working the switch back and forth through the on/off positions to see if that cleans the contacts.
 

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Discussion Starter · #8 ·
I found the problem and thanks to all who provided suggestions. It wasn't the switch. I pulled the plastic cover off the back of the switch and did a continuity check between the brown/white wire terminal and the brown terminal and it had connectivity with the key in the first position.

I then checked continuity from the brown/white terminal on the switch to the brown/white female pin connector in the round plug. There was no continuity. There didn't appear to be any breaks in the wire so I pried the plastic cover off the plug. As soon as I did the brown/white wire fell out. It had corroded away from the connector.

My question now is how do I remove the female connector terminal from the plug?
 

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Make sure all the pins are making good contact with their sockets in the round plug that connects the switch wiring to the harness. If that doesn't solve it, before taking the switch apart, I'd try spraying some WD40 into the key hole and working the switch back and forth through the on/off positions to see if that cleans the contacts.
Winner winner, chicken dinner!
 

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Discussion Starter · #12 ·
I was able to remove the female terminal from the plug. I used a paper clip wire to depress the tab that holds the connector in place. Then I tapped on a screw slightly larger than the connector to push it out of the plug. The switch is now re-installed and the tail light works in both the first and second key positions.

A little background info...I just replaced the entire wiring harness. The previous owner had modified it by relocating the ignition switch up to the handlebars and had cut off the ignition switch plug, the stator plug and had spiced the leads to the harness. Also, the harness he had did not have turn signal wires. I replaced that harness with a stock one and put the ignition switch back in its original location. Everything works except the turn signals won't flash. I had two flasher switches but both tested out bad so I've ordered a new one.

I also replaced the engine as the last one had serious knock and I wasn't up for rebuilding it. I bought the used engine on ebay. I've installed it and compression in both cylinders is over 160 but I haven't tried to start it yet.

I'm not trying to restore the bike, I just want to get it where its reliable to ride. Its in pretty good original condition now except for new aftermarket mufflers.
 

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Good job ferreting out the problem and getting the whole wiring situation back to normal. The flashing issue would simply be too low a voltage (unless you've replaced the turn signal bulbs with LEDs), flashers often don't work well until the bike is up to speed as the charging systems on these old bikes are marginal at best. If you haven't done it yet, you should change the separate rectifier and regulator with a modern combo rec/reg assembly, you'll get the most out of it that way.

I'm not trying to restore the bike, I just want to get it where its reliable to ride. Its in pretty good original condition now except for new aftermarket mufflers.
As for the bike... pictures - we want pictures!
 

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Glad I didn't post anything. First thing I thought of was on my 450 the taillight doesn't come on in first position until I turn the headlight switch on but now I see your bike switches aren't original. Glad you found the problem, vintage connections is a great source for connectors.
 
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