Topic: K1 CB750 turn signal short

[catdogboy]

Anybody have an experience with their flasher circuit having a short? I actually replaced the harness just to have the same problem. I can get everything to work but the flashers. In fact now if I just plug in the new (OEM) flasher relay it blows the fuse without even having the flashers on!

The problem first arose months ago at a traffic light, I turned on my signal and popped the main fuse. I quickly realized if I unplug the flasher really, I'd have no flashers and no blown fuse. I replaced the flasher relay and no difference.

Cat Dog Boy is mystified.

Any help would be much acknowledged.

With all best wishes

[69cb750]

A turn signal wire is shorted.
Left or right ?

[Bodi]

The flasher circuit has the actual flasher unit powered when key is on. Its "flashing power" output goes straight to the switchpod and when the signal switch is used for left or right this flashing power is connected to the signal lights. Their bulb load causes the flasher to start flashing.
So if the fuse pops without a signal on, the problem is further down the circuit - either in the wiring or in the switchpod.
Unless you have a 3 terminal flasher with the ground connected, the only current path to ground is through the output wire. If you DO have a 3 terminal flasher, try disconnecting the ground wire. There are several types of flashers, some have two outputs (a second output for trailer lights or a dash idiot light) rather than one output and a ground: if you have installed one of those then the fuse will blow immediately (or it will flash super fast a few times first) when you turn the key on.

[catdogboy]

Thanks for the input. There are only two wires from the signals, one to the bulb, and one to the ground inside the headlight bucket on the stem bolt. The bike has Wixom Bros vintage hard packs with the same two wire hook up for the rear turn signals. I follow the bike wiring diagram and the green wire from the flasher unit goes directly to the switch, then on to the headlight bucket. The short occurs without even having the turn signals hooked up. I am reluctant to pull the turn signal harness from the handle bars, but unless I have the new harness hooked up very wrong, I think I need to examine the wiring in the handle bars at this point. One more go around on the wiring diagram, then into the handle bars I guess. I should test the circuits to the switch for continuity, that would make sense.

Happy trails, CDB

[HondaMan]

There should be a Black wire to the (2-blade) flasher and a Grey wire. The Black is +12 volts Ignition power. The Gray wire goes to the L-R turn signal switch by going fron the flasher to the headlight bucket, where it then goes to the L-R switch.

So...unplug the Grey wire inside the headlight to see if it prevents the fuse from blowing. If so, then the trouble is in the turn signal wiring, possibly inside the handlebars (this might be near the switch). The 750K1 turn wiring is pretty simple: it goes from the headlight to the L-R switch and from that switch as Orange (one side) or LightBlue (other side) wires to the turn signals. Sometimes the K1 had a White stripe on the Orange or LightBlue wires, but this more often was seen in the K3 and later harnesses.

[catdogboy]

Thanks very much for the support!

 I am embarrassed to say what the problem was. But share and share alike! At the flasher point there are three wires coming from the harness. The light gray, and black are grouped and there is a solid green just next to it. For reasons I cannot now fathom, I was trying to plug the green and the black to the flasher relay. My only defense is that I am a bit color blind and was following the wiring diagram, I thought, to the letter. So I replaced the harness, (which did  have a few splices where it continuously bends right by the tank and triple tree), when in fact I probably just had a blown flasher relay.

Problem solved, 'Ruby Baby' is very happy again.

Yours truly, with all humility, Catdogboy

[HondaMan]

Ruby Baby is gorgeous!
I have her half-brother in my garage now, a 750K5 I rebuilt some 9 years ago for its owner. After he came back from Afghanistan, et al, he took it to a local bike hack (that's what I call them around here) who said he could make it run again after sitting for 5 years. After he was done with it, it needed some serious repair, so it's back with me again until I get it fixed up right: it is one of the best paint jobs I ever did, it is named "Baby", and looks much like yours!

[newday777]

Thanks very much for the support!

 I am embarrassed to say what the problem was. But share and share alike! At the flasher point there are three wires coming from the harness. The light gray, and black are grouped and there is a solid green just next to it. For reasons I cannot now fathom, I was trying to plug the green and the black to the flasher relay. My only defense is that I am a bit color blind and was following the wiring diagram, I thought, to the letter. So I replaced the harness, (which did  have a few splices where it continuously bends right by the tank and triple tree), when in fact I probably just had a blown flasher relay.

Problem solved, 'Ruby Baby' is very happy again.

Yours truly, with all humility, Catdogboy

You aren't the 1st to fall on the green wire at the flasher relay. Many have asked what it was for over the years, on many Hondas. Well done getting Ruby Baby happy again.  Mighty fine looking too.
I was looking at the house across the street in the picture noticing the stone pillars and walls along with the house architecture, trees and the bushes, are you in New England? It looks like New Hampshire to an extent.