Topic: Lost all electrical powere!!

[Bo24]

I just joined the forum in hopes someone can hepl me with my 1975 CB750? The other day, I went to ride and my start button didnt work, but everything else was fine. I kick started it and rode for a bit. The next day, I went to ride again and I had nothing! No lights, dash lights, starter..nothing!!
I checked the battery voltage and that was OK. With my tester I had power to the ignition switch, but only one fuse out of the 3 worked. I crossed the selnoid and it turned over, but not sure if that means it works or if it is shot?
I was also wondering if I took the red and black wires off the ignition swith, do I also have to do the same with the two tan wires?
I am not a fan of electrical so any help in which direction I should go in would help greatly!!

[Bankerdanny]

Unplug the terminal from the bottom of the ignition switch (it's easier to get at if you remove the headlight shell) and check the spade connections. They are held in place by a mushroomed copper rivet and over time the mushroomed top works loose.

This happened to me about a month ago on my 550 with less than 10k miles on it. No prior warning of any kind, just sitting at a stop light it died, then restarted, then died again and nothing. Dead as a doornail.

It was 11:30pm, but fortunately there was a grovery store where it died, I was close to home and a passing stranger happened to be a 400/4 owner, so I parked the bike and he gave me a lift home.

The next day I hot wired it to get home ((search Dead as Generalissimo Franko for details on how to hot wire), then took the switch inside and soldered up the spade at the rivet.

[Bo24]

I'll check it out when I get home!!

[Bo24]

Will all 3 fuses run current even if the ignition switch is shot? I have current to one fuse, but not the other two.

[Bankerdanny]

I have a later model 550, so what applies to my bike might not also cover yours, but I believe that only the main 15 amp fuse should have power when the switch is off.

[Hush]

Yep Bankerdanny I believe all our Hondas work like that, one hot wire from the battery to the ignition then the ignition disperses it from there.
Sounds like your battery is fine, yes to checking the connectors in the headlight bucket, would also check the connections at the solenoid.
Pull them apart don't just lok at them and think they are OK as that crud gets in there easy as and disrupts the connections.
At least your problem is only in the wiring, it should be a matter of tracing that fault.

[ekpent]

Pull your tank.especially if you have a handlebar mount ignition relocation set up,like the little plate mount set up and make sure the main harness connection has not been  compromised and then give the ignition-key area a good inspection.Harness connection or wires can get pulled or stressed when turning etc. with that set up cause wires are to short if not routed correctly. Pictures rule if you have any ??

[Trav-i]

Correct me if I'm wrong but yourbike still has the key switch under the tank right?  If so pull the tank and locate the switch plug.  Don't unplug it just check for power at the red wire (it should be hot all the time, check it on the switch side of the plug.  If you have voltage there, then turn the key to ON.  All the rest of the wires should power up, checked on either side of the plug.  If not then the switch is bad (happened to a friend the night before the relay ride started), if they do power up I would check the fuse box connections and fuses next.

Just my .02

Travis

[Bo24]

That all sounds like great advice...I took the tank and headlight off to check for any wire disconnect or shorts and everything looked good. When I crossed the selnoid and it fired, does that mean it is good or it is shot?
When I get home I will play with the ignition switch.

One more question, do I need to disconnect all the wires from the ignition switch (red/black and brown wires) inorder for my starter button to work on the handelbars? Or just the red and black? Sorry,kind of a dumb question. I suppose I will find out when I get home but wanted to know what to expect when I work with the ignition.

[bollingball]

You have not proved the start sol. to be bad or good you just by passed it.

[dtmmil]

I had trouble on my 78 with the main red wire down by the reg/rect at the white plug in. Mine corroded and started melting the connector. It would lose power, but most of the time it would also blow the fuse.

[Bo24]

I'll let you all know what I find out. Thanks again!!

[Bo24]

Got it fixed!! It was the ignition switch!! The previous owner must have replaced it at one time and wired it all goofy. After stripping all the wiring off the old switch, I found one wire that was hooked to nothing. That was confusing me earlier. Put in a cool toggle switch and it works and looks like a champ!!

Thanks again for all your help!! I will definitely be back if I have any other problems I can not solve!

[Trav-i]

Glad you got it sorted!!