Topic: ignition switch(?) problems

[rebel327]

First post for a noob.  I am new to the sohc 4 and my first bike on the street.  I just bought this bike the other day, it ran good but then the other night it won't start.  The battery is good but there are no lights or anything functioning except the radio in the fairing.  I'm no electrical wiz. I think everything else on the bike comes through the ignition switch. I checked the main fuse and it seems to be good. I'm not real sure what to be looking for in a bad switch. Any help from anyone with an ounce more experience than I have would be helpful.

[dustyc]

What year and model?   It's necessary to know what you have for nearly any question. 

Go ahead and replace the fuse and clean the holder.  I would suspect that before anything else.  Sometimes they look good and are bad.    Caig Deoxit is good for cleaning the connectors, fine grit sandpaper will work also. 

With a volt/ohm meter you'll be able to test the continuity of fuses and wiring using the resistance(ohms) setting, and measure the voltage at various places in the harness using the DC volts setting.

Some of the ignition switches come apart easily and can be cleaned and reassembled.  Or replacements are pretty cheap.

Congrats on the bike. 

[rebel327]

The bike is a 1978 cb750k8. With a little more time to look into the problem I've found that the spot for the main fuse is melted following those wires to the closest connector I checked all the slots with the multimeter for resistance and found that the two slots connected to the red wires are not showing any resistance.  It looks to me if that if I'm reading the wiring diagram right ( and there's a strong possibility that I'm not) that the fuse is connected to the main switch and the starter magnetic switch. I'm going to check both though I'm not sure where that's going to take me.

[mark]

There are numerous threads on this board about fuse box issues. Like this one here:

http://www.sohc4.us/forums/index.php?topic=20035.0

Lots of other problems seem to live in the 'rats nest' inside the headlight bucket.

Happy trails.