Topic: dead bike (electrical problem) heeeeeeellppp

[Ceej]

Hey guys, I'm looking for some help here

So, just rode my bike down the street to fill up the tank, and on the way back home, bike goes dead while im just cruising down the street at about 30.  I pull over, try to restart it, nothing.  Everything is dead, I get nothing when i hit the starter or turn the key.  Headlight wont come on, none of the warning lights come on.  I checked my battery ports and looked in the headlight to any disconnected/loose wires, but everything looked normal in there.  I'm guessing that i might have blown a fuse?  Although im not sure how this would have happened?  I took of the handlebar controls and found that there was somthing loose shaking around in the left side controls, I have attached a picture of it, coudl this little thing be the problem?  I have no idea what it is.  So, If you guys have an suggestions on where to check and look for electrical problems or fuses please let me know.  Any advice is greatly apreciated.

EDIT:  This is for a 1974 cb750 (forgot to include this)

Thanks,
CJ

[Scout]

Well, I would check the ignition switch. Turn the key to on, and play with the cables underneath. Mine died just like that, and it turned out that the ignition switch connector was in pretty bad shape, and the inside was even worse. I took everything appart, cleaned it, stretched the little springs, and it's like new.

Scout

[Ceej]

ok, I went out and took off the ignition switch (had been relocated to the bars) and jiggles the wires underneath, and it came back to life for a second.  I started it up and it idled for about 10 seconds and died.  Jiggles some more and the same thing happened again.  But now I cant get it to come back on again.  I looked at my ignition swtich and it looks pretty good, although im not sure how to take it apart.  The wires comeing off the back are fine and connected well.  So im thinking maybe its on the other end of the ignition wire.....which i have no idea where it is.  I took off the side pannel and exposed all that wiring, my guess is that it connects somewhere in there, but i couldnt find a match for the wires that were coming out of the switch.  What connections shoudl i check at the other end of this and where can i find them?

Thanks
CJ

[fourplay]

CJ,

Your going to need a wiring diagram for sure. I am new to the site but there might be one on here.

It's hard to diagnose electrical. You can have some seeming clean connectors and they still won't be making contact. If you are pulling on something and it is coming back alive, I would look in those areas. If your wiring is as old as your bike, it can have broken wires inside the insulation. Even stranded wire will break after it gets old and with repeated flexing. This can be happening where the wiring goes in to the headlight at the area around the forks. This area sees a lot of wire harness movement.

If you don't have a repair manual, get one.

[Jonesy]

The part in your hand looks like the little pin that keeps the control pod fixed in position on the handlebars.

The earlier keyswitches have a rubber boot covering the back of the switch. Snake back this boot and you will see the wiring pigtail attached at the back. Check for any broken wires there.

[Ceej]

The earlier keyswitches have a rubber boot covering the back of the switch. Snake back this boot and you will see the wiring pigtail attached at the back. Check for any broken wires there.

I already removed that boot and those wires seem to be fine, Now im wondering where the ignition switch wires lead to?  This im not sure of.  I tried downloading the wiring diagram form this site but niether of them would work.  Anyone have another source?

[Jonesy]

Try out www.oldmanhonda.com. He has a nice interactive wiring diagram that you can shut segments of it off, so you can focus on the parts you're trying to trace, without the clutter of the stuff you don't want. It's helped me out a couple times. It's for a K1, but they are very similar, at least for what you are looking for...

On the K4, the main wiring harness is routed along the main frame rail under the gas tank. From there it connects into the electrical tray under the left sidecover. You are looking for a solid red wire (hot wire from teh battery) or a solid black wire (main power feed from the keyswitch).

Hope this helps...

[jsimon]

same thing happened to me last night, riding along and all of a sudden my '74 cb 750 dies, no lights, no electrical, -- have checked ignition switch and connections, all appear fine, was not having any trouble previously, ride regularly as i live in the central valley - could this be a stator problem? any suggestions welcome!!!!

[endobendo]

I had the exact same problem in the middle of a road trip with my 76 F bike.  Although our keyswitches are different, you may be experiencing similar woes.  The bottom of my switch had popped loose so the contacts weren't fully mating, which caused some arcing, then a sudden failure.  I  hot wired the thing on the road to get to a hotel, which is scaringly easy.  In the hotel I cleaned the contacts, put the switch together tight with a zip tie, and cleaned every contact I could find in terminals and the fuse block.  I made it 600 miles home with no problems and put another 300 miles on it before I tore into it again.

With wiring, definitely look for a diagram and be patient.  Clean all corrosion you can, in sockets and fuse terminals.  It is also a good idea to recrimp connectors or replace altogether old connectors as they all add up to more resistance.  I actually replaced a lot of my old socket connectors with a permanent connections and shrink fit tubing.  Also, the ~$180 I spent on a new Honda keyswitch was some of the best money I spent.  Aftermarket keyswitches can be pretty crappy.

[hcritz]

Hey Ceej;
Although it sounds like maybe you have pinpointed the problem to the ignition switch...
Carefull check the fuses...The main could be bad...
Take the fuse out of the holder...it seems they like to fail at the connection to the end piece instead of in the middle where you can see. Pull on the end caps and make sure all is still connected in side the fuse. or better yet check with a meter.
Mine did the same thing at the gas station.

[Scout]

I think what helped the most with mine was, after taking the bottom of the switch out, separating it, and cleaning the rotating conacts really good with sand paper and some electrical cleaner, I also stretched the springs that push the connectors onto the plate. Since then, I can wiggle the crap out of the ignition cables, and it's rock solid... I would try that first, as it's a lot simpler than playing around with all the wires...

Scout