Topic: New bike. Need help with some electrical issues

[daft_soul]

I picked up this 1976 cb750 supersport on monday. Everything that you're about to see was done by the previous owners...so its not my fault. The bike runs and I've ridden it to work once this week and around the neighborhood. I really don't feel comfortable going a far distance until I get some of these issues worked out though. I've looked at a wiring diagram and thats helped me understand it some...but going behind someone else's ghetto fixes is making it worse.

So lets jump right into it...

Turn signals - front signals function properly. Rear signals are not present, neither is wiring for them.
Rear brake light - lights up when front brake or rear brake is pressed. Constant on doesn't work.
Horn - doesn't work. Horn is down by the headers right? Its covered in grime also.
Headlight - doesn't work. Hi/lo switch has no effect. Currently there is a wire spliced into the blue low beam wire, and that wire connects directly to the battery to work the headlight.

On to the pictures...

Underseat going to the tail. Everything except the turn signals seem to be hooked up...


I'm not retarded...that melted harness looks bad. Also the aluminum foiled fuse...Ironically I tested the fuses with a multimeter and the aluminum foil is the only one I got 12.XX volts on with the key in the on position...bike not running though. The other fuses came up with various small numbers. Also, that green connector on the right looks like it should be hooked up somewhere...but there is no place for it on that silver circle thing.




This black wire connector looks a lil burnt up. Also the headlight splice I mentioned. Everything else in the bundle looked fine as far as I can tell and had a wire running into and out of the connector.




I may also be having charging issues as well but I wanna get this stuff taken care of first. I have a battery charger and multimeter. Let me know if there are any other major wiring areas that I don't know about and I can go outside and take some more pictures. Thanks for the help

[TwoTired]

At the back, orange and Lt. blue power the rear turns sigs with Green being the ground return.

Buy a new fuse box from Hondaman.

Replace all melted wires and get a new connector for  vintageconnections.com

The green wire next to the turn flasher is for use when a three terminal flasher unit is employed on some models.  Ignore it, if you don't have one of those.

Do the ohms test on your rectifier before powering up with new/replaced components.

Fix what you know is bad, and then move on to focus on what still doesn't work.

[ChuckG750f1]

I agree with TwoTired.  Do you know that the diagram you have is the correct one for the bike you have?  Also, if you read the supply voltage across a fuse with power applied, it means it is blown.  The tinfoil is not making a connection (this may be a good thing).  A good fuse will not read voltage across it and out of the circuit it will read ~0 ohms.  On your bike, you should see two main bundles of wires coming from the handlebars down to the junction box next to the horn.  The larger of the two comes from the left switch housing and the other one from the right.  If you have the correct diagram, you can disconnect those wires and use your ohm meter to verify the workings of switches.

[LesterPiglet]

Also, blue is high beam.