Topic: Clutch brake light cable

[ron.cieri.313]

Hi all...regarding my Honda CB750 K (1976)...on the left side of the handle bars, just beneath where the clutch cable enters the clutch lever, there is another cable which i believe is suppose to turn on the brake light when the clutch lever is compressed.

Well, mines been disconnected/flopping around for some time so I got a new one...easy enough to install, only the wires are color coded differently then the original...original had two wires, a green-red one and a solid green one...new one has a green-yellow one, and a solid black one...how do they match up?

Also, i tried it both ways...neither way seems to turn on the brake light...am I missing anything?

...thx...ron.

[bryanj]

Nothing to do with brake light, its part of the starter safety interlock system

[ron.cieri.313]

Ah, excellent...so it will allow the bike to start if the clutch is pulled in?

[Fritz]

Ah, excellent...so it will allow the bike to start if the clutch is pulled in?

Correct. The starter relay is connected to ground either by the neutral or the clutch switch (or both

[ron.cieri.313]

Great...I guess I can see which way works now by trial and error...but any guess on the wire color matching...ie., which one matches the original green with red stripe?...my new switch comes with a green and yellow striped wire or a black one.

[Fritz]

but any guess on the wire color matching...ie., which one matches the original green with red stripe?...my new switch comes with a green and yellow striped wire or a black one.

Mmmm. The wire colors of your new switch indicate that it could be a break switch, which connects to ignition (black) and not to ground (green) like the clutch switch. But why would you want the break light to turn on whenever you pull the clutch?

However, if it's really a clutch switch, connect the two wires of the switch to green (ground) and green/red (starter relay) on the loom. The order is not important as the switch will work both ways e.g black to green and green/yellow to green/red or the other way around

See http://www.sohc4.net/index.php?q=node/135

[ron.cieri.313]

Well, I tried it two different ways but with the new switch installed it does not turn over at all with the bike in first and the clutch pulled in.  I even tried taking the clutch lever off and directly keeping the switch pushed in with a pencil to be sure...no luck.

It does look way better than a dangling wire that used to be there when it was broken but obviously not functioning properly...here's my real problem though...now my turn directionals...or front "winkers" do not blink...the turn signal indicator on my display blink, and the back turn signals blink, but not the front.

I was careful when I removed the old clutch safety wire to find the leads I was taking in out from and to plug the new wire into that connnection.  Do you think I wire in that tangle of wires just came loose?...or maybe my signal relay decided to go at the same time?...other ideas???...thanks all...ron.

[Gordon]

If the rear turn signals are flashing then the relay is working fine.  There's only one for all four signals.  If the front signals were working before you started working on the clutch lever switch, then look for disconnected wires in the headlight bucket. 

[ron.cieri.313]

Ah, thanks Gordan!

I did find an empty black (i believe) connection but i thought maybe it was an extra available for an add-on...but me thinks, this is possibly the culprit?

[Gordon]

I don't know the wire colors for the front signals off the top of my head (light blue and orange maybe?), but it won't be the black wire.  On the sohc4's black is switched + 12v, so it should be powered anytime the ignition is turned on.  Do you have a manual with a wiring diagram? 

[ron.cieri.313]

Yep...i've looked at it in dismay several times...do you think the loose/unplugged connection is in the back of that headlight mess?

[Gordon]

Yep...i've looked at it in dismay several times...do you think the loose/unplugged connection is in the back of that headlight mess?

Who knows where they'll be?  Follow the wires starting from the turn signal stems all the way back to where they are, or should be connected. 

[mystic_1]

Here's a schematic of the starter safety system, it may help your diagnosis.

mystic_1