Ground wire from battery to frame?

For rookie electricians ... can you run a wire from the battery negative terminal to the frame as a ground for your bike? I realize there is a ground in the harness somewhere but could you rig a ground wire this way as backup or insurance against electrical gremlins on a 30+ year old bike? I have a 1977 KZ650 with separate rectifier and regulator.

I believe most Negative(-) grounded bikes have/had the battery terminal on one end an usually an engine mounting bolt on the other. If you think yours is failing, go to a welding supply store and purchase some 6 gauge welding cable. It comes in two colors RED and BLACK. I think they sell it by the foot.

I'd also suggest upgrading your Positive (+) connections too as they need to have the same size conductors as the Negative one will be.

If they can't crimp/swage on the terminal lugs you need, try a battery shop as they have the special tools.

Actually, the 1977 KZ650c came with a ground wire from the negative battery post to ground (on the rear right side of engine). This wire also has a smaller diameter lead that goes to the wiring harness. See wiring diagram for details:

KZ650C1 Wiring

yea the frame will work if you can find a good location that aint getting wet and muddy.

The engine is a good place too...

Red wire is +
Black wire is -

Usually that is.

the engine cases themselves give the best grounding point for engine related things (ignition mostly) the frame is a good ground source for pretty much every thing else i like to keep the two seperate if possible no reason other than i have always done it that way.