Ignition switch\turn signal switch

[rcuttler]

I've got a '77 CB750 and the key ignition switch fell apart. It was easy enough to remove the original switch but almost impossible to replace it with a new one. Too many wires and brake lines, etc. to get my hand in place to thread the new switch mounting screws in. So, as line of easiest resistance, I bought a replacement switch for an earlier year, one that is meant to mount under the tank. I've hooked everything up electrically but not yet a permanent location, and everything works. ALMOST. The turn signals don't work. It was easy enough to locate the problem, but not the cause. The problem is the flasher unit is not getting a ground from the turn signal switch. This would be the gray wire at the switch, not being grounded at the flasher. If I put a jumper to the flasher the lights flash as normal. Removing the switch unit from the handlebar and opening it up wasn't much help. There's numerous wires going to the switch that are so crowded together that I can't even get a pointed probe to the gray wire. I'd have to disassemble the internal parts of the switch and who knows if I would ever get all those wires back in place. I know this is the next step in diagnosing, but it's hard to believe that out of nowhere the switch went bad when the key switch fell apart. I'm guessing that in some way, that replacing the switch with one that is not an exact duplicate, is the problem. The main difference between the OEM and the replacement is the plug, and I'm not using the plugs at either end. I cut them off and soldered the wire connections. I'm hoping somebody has more knowledge and or imagination than I have, and can point me where to look further. TIA

Bob

 

[rcuttler]

I've got a '77 CB750 and the key ignition switch fell apart. It was easy enough to remove the original switch but almost impossible to replace it with a new one. Too many wires and brake lines, etc. to get my hand in place to thread the new switch mounting screws in. So, as line of easiest resistance, I bought a replacement switch for an earlier year, one that is meant to mount under the tank. I've hooked everything up electrically but not yet a permanent location, and everything works. ALMOST. The turn signals don't work. It was easy enough to locate the problem, but not the cause. The problem is the flasher unit is not getting a ground from the turn signal switch.
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Well, I solved my own problem. I didn't want to take the turn signal switch apart, but the wiring diagram showed the ground wire was coming from the headlight bucket, and in fact that gray wire originated in the bucket. That means the frame ground had to be through the headlight bucket, which I had already disconnected to get my hand in place to remove the broken key switch. So just put a jumper wire from the bucket to a frame ground, and WALLA, turn signals worked. The most difficult jobs can be upended by the simplest things. What a surprise. <g>

Bob

 

[hinksy]

If you were to redo it , try and take or loosen off the headlight and pull it forward . That will give you the room to get in there . First time I went through the process of rewiring mine , I just kept thinking I was never going to get the hang of the coloured spagetti , but I did . Took a few goes and I did release some of that magic smoke , but I got there in the end