Topic: TailLight Wiring- what connects to what?

[HondaSolo]

whats up?

Got my bike up and running! bought it a few months ago, been restoring it and Ive got it in a ride-able condition, ive been tearing around my neighborhood, no doubt getting all the snowbirds down here in AZ angry from all the noise haha.

Anyways.... When i bought the bike(1973 cb750 k3) the rear taillight was all disassembled and electrical work is just totally over my head.
I grabbed my pops to take a look at it and thought he would have an easy time about getting the rear brake and running lights working seeing as he is electrical engineer and works for NASA. no luck. one way we had it wired the brake lights came on, then reversing that setup we could get the running lights working but never at the same time.

does the circuit reverse when you hit the brakes and turn off the running lights to illuminate the brake lights?

Ill post pics of the the wires and if someone could let me know just what the heck is supposed to connect to what I would be very extremely grateful. I'm worried I'm missing a wire or that this PO wired something differently.

2nd light question: should the hand brake also be illuminating the brake lights or just the foot brake? because right now the brake light only comes on when i press the foot brake.

What does the yellow and green connect to and what does brown connect to in the rear light case?
What does the brown, green and long green one from the bike go to?

it all just seems crazy to me that one has 3 wires and the other has 2 and the results were getting are even more confusing as I mentioned above.

Ive looked at the wiring diagrams but they dont seem to give this level of detail, at least that i understand, of what actually connects.

please tell me if this set up looks typical or what I'm missing

Thanks guys, this will bring me the last step basically to getting the bike totally street ready.

[DH]

There's a male spade prong at the bottom of the socket housing (shown in pic) . Solid green(FROM THE MAIN HARNESS) goes there. Green/yellow (shown) goes to the main harness green/ yellow.
Brown (shown) goes to main harness brown.
                                                      solid green is ground
                                                       brown is fused power
                                                       Green/yellow is brake lite

You really should pick up a tail light assy with socket and wiring and gasket.
Yours is obviously modified, or, for a different bike and the reflector is missing. I've never seen anything with those small side lights either......interesting. Anyhow...
There are no running lites on the REAR of the bike, front only.
A pressure sensitive switch is mounted to the front lower triple clamp that activates the brake light. It's tee-d into the front brake hydraulic hoses. Black wire going to it (switched 12v.), and a green/yellow going back to the light, joining the green yellow from the rear brake switch as it does so. Front running lights only come on with headlight switch on, and do so by design. Two filament bulbs
in fronts, one filament in rears.

[LesterPiglet]

The fronts are the only running lights, the rears are ordinairy winkers.

Hmm, never noticed those small bulbs. So that's what you mean by running lights. They be useless with the normal bulb working.
Your front brake light switch should be on the brake hose.

http://www.cmsnl.com/honda-cb750-four-k3-usa_model481/partslist/F++05.html#results

[DH]

The fronts are the only running lights, the rears are ordinairy winkers.

Ya beat me to it les, I was late editing....sorry about that

[LesterPiglet]

Heheh, did a bit of editing myself.

[HondaSolo]

Thanks guys, this is shedding light on the problem. It helps a lot just knowing that this tail light has been messed with, so I can rule out trying a current config. So in a normal stock brake light there would just be the 2 normal bulbs? How do they work, does one illuminate when lights are turned on and the second bulb only illuminates when the brakes are pressed?

I'm pretty sure the light is for my bike, probably just missing the reflector though. I can't tell in the picture you posted DH but does your tail light only have one bulb, in the middle of the reflector?

I guess what I meant by running light was just the tail light being on when the headlight is turned on too, my bad.

Is it worth trying to rewrite and figure out this tail light?  We got a pretty good big motorcycle junk yard here in Phoenix that always has several cb's in it that I could possibly go pull the whole tail light off of for my bike. Thoughts?

[LesterPiglet]

There would be one bulb that has two filaments. Just get the correct light. Use the link I posted earlier, you will see a diagram of the light.

[DH]

There would be one bulb that has two filaments. Just get the correct light. Use the link I posted earlier, you will see a diagram of the light.

..... +1 ..and get the parts in the pic WITH all bolts/hardware. It never hurts to have extras of that stuff. Install an 1157bulb, bolt on, connect leads, done. If you can get it with a good lens its even easier. Leave lens on,
2 bolts hold it on from the back, unplug leads, done. put hardware, gasket, and cushions in pocket