1981 Honda CB750 Electrical Question?

Question

I have a 1981 Honda CB750C that has run perfectly. Now, when I turn the ignition, I get no power. No headlight, no panel indicator lights, no horn, no starter, nada.

The battery is brand new, and the short does Not drain the battery. I've replaced all fuses including the fusable link by the battery.

Can anyone give me any ideas as to where this short may be, and how to correct it?

Thx

JH

Answer 1

Check your ground strap first. All power flows through it.

Answer 2

First off, I doubt that it is a short. A short makes smoke, sparks, fire, running and screaming.

An open sounds more logical. Perhaps the ignition switch is broken. Maybe the fuse to the ignition is blown. Maybe a wire is broken along the way.

My advice would be to check the ignition and see if there is voltage to it. IF there is, turn the switch on and see if there is voltage leaving the switch. If there is, just keep checking the primary voltage readings to the coil in and the coil out.

By any chance does your lights only burn when the engine is running? Does the switch control the lights on off?

I think you will find your problem between the battery and the output of the ignition switch. Good luck. Pops

Answer 3

It has to be in the switch, get a tester with a point, and check the wires just before the switch, and just after the switch, see where the power stops, its the only thing that can cause a complete loss of power, except battery and battery connections. One fuse won't cause it, you would still have several other funtions like horn, or indicator lights.

Answer 4

Cb750 Ignition Switch

Answer 5

Power flow -
Battery (+) - starter solenoid - red - fuse box - main fuse - red - ignition switch - on position - black - power the bike.

Answer 6

You have a open circuit at the ignition switch.Check switch for broken solder joint at run contact.Check for power to switch.