No electricity. Need help.

[colab]

I officially can't figure out why I'm not getting power. No lights. No anything. The battery is holding charge and the main fuse seems fine.

Any electronics guys out there want to make some dough and help me get back on the road. Drop me a line. Downtown Toronto preferably.

Thanks.

J

72 cb750 k2

 

[Redbird]

Unfortunately you're going to have to start tracing wires. Grab a test light and start with the ignition switch. Make sure you have power going in AND coming out.

 

[colab]

I can't seem to find it. Spent hours with a multimeter testing the wires. I'm suspecting the starter solenoid might need replacing. Anyone know where to get one in Toronto?

 

[colab]

So here's the latest.

All of the bulbs seem fine. Ground seems fine. The connections near the battery seem fine and power seems to make it to the coils.

I was testing continuity where the ignition key assembly meets the wiring harness. At the brown connector where it plugs into the harness. All of the wires seemed fine except the black wasn't giving me a reading. So I poked a piece of wire in to jump the black connection. I got the headlamp to come on for a sec... which hasn't happened in awhile... and got a little smoke. So it could be the connection here. I'm also suspecting the starter solenoid.

Question. With respect to the brown connector where the key assembly attaches to the wiring harness... should I be able to pull this apart? Is there a secret to it? I couldn't get it apart to check the wires inside. Shamefully I even tried the ol butterknife method. But it won't budge.

Help. I want to get on the road before the summer is gone.

 

[mindactivated]

Check your main fuse again? Sometimes they may not look blown but can be defective.

 

[colab]

The main fuse is good. I think I'm going to have to take it to someone if I can push it out of underground parking.

 

[colab]

The main fuse is ok. Are there other fuses I should check? I'm lost when it comes to electrical.


Another question... I can't seem to unplug the key ignition from the wiring harness. How does that connector come apart. I keep wiggling but it doesn't want to budge.

 

[Redbird]

Ok, I'm not familiar with your bike specifically, so any info I can give is going to be generic.
Yes, there should be another set of fuses. Probably behind a side panel. There's usually fuses for headlight, taillight, and main.
The connector at the ignition probably has some sort of locking tab on it. You'll have to push, or lift, a tab in order to seperate the two.

You say you're getting power to the coils, do you get spark?

 

[colab]

No spark. No lights. No nothing at the moment.


The battery checks out. Main fuse is good. Replaced it just in case. Getting continuity on all wires near the battery.


My wiring diagram just shows one fuse... and I can't seem to find any more in real life.


I'm at a loss.

 

[Redbird]

Ok, I could be wrong about more fuses.
With the ignition turned on, do you get 12v on both sides of the fuse?
If yes, go to the connector at the key switch, according to the diagram there should be four wires: red, orange, black, brown w/white stripe.
With the ignition switch off, you should still have 12v to the red wire. With the ignition switch on, you should have 12v to all the others.

 

[colab]

I get 12v if I measure from the negative battery terminal to either side of the fuse... But I get nothing if I measure from the positive battery terminal to either side of the fuse.

 

[GreasyJ]

You won't as there is no complete +-circuit, stick with testing the positives to ground (-) for voltage thru the circuit. Check that your ground is solid, securely connected and not corroded as well. Move on to the ignition switch now, and so on...

 

[colab]

Progress... at least I think I'm on to something.

If I jump the red wire coming out of the key ignition to the black wire on the side of the wiring harness the bike lights up. I can turn it over. I can't start it as the tank is off in order to get to the wires.

Does this mean my key ignition switch is bad?

Also... It felt as if the wire heated up slightly. Not too badly. Just a little. Could that be considered normal?

 

[Redbird]

Yes, it sounds as if you have a bad ignition switch.
You can check to see if it'll run by setting the tank back on, reconnect the fuel line, turn the petcock on for a minute to fill the float bowls, and then remove the tank again. Full float bowls should allow the bike to run for atleast a couple of minutes.
As for the wire heating up... if the jumper wire was of a smaller diameter (higher gauge #) than the OEM wiring, that would cause it to heat up.