TOPIC:

12.07 Volts Key on/ Engine off

12.40 Volts Key off/ Engine off

loudhvx wrote: The problem is that is it masks the real problem of the voltage loss. This can lead to an over-charging problem on some bikes which will boil out the battery. It's always a good idea to address the real problem to prevent more problems in the future.

+1 check voltage drops at connectors, fuses, and ignition switch. And the fuses themselves go bad often.

bountyhunter wrote:

loudhvx wrote: The problem is that is it masks the real problem of the voltage loss. This can lead to an over-charging problem on some bikes which will boil out the battery. It's always a good idea to address the real problem to prevent more problems in the future.

+1 check voltage drops at connectors, fuses, and ignition switch. And the fuses themselves go bad often.

Also carefully check ground wires where they attach to the frame or engine. Be sure the connections are spotless and tight.

I have next week off of work so will have time to go thru all the connections. I really don't think it's that for when I started this bike as a non-runner to what it is now, I paid pretty close attention to all the electrical connections when I put it together. But who knows ?

When I measured the voltage at the coils and read 8.98 Volts, what should it be reading ?

As I said earlier, these are the original coils and wires. Do you think I should replace them ? I remember the Primary and Secondary ohms resistance was well within spec. according to FSM.

Voltage at the coils should not be more than two or three tenths of a volt less that at the battery terminals.

So as I said earlier, is it a possibility that just the coils are weak ?

Hi kzdcw,
Possible but unlikely if, as you say, the primary and secondary resistance is in spec. Replacing the coils won't fix the source of the voltage drop.

Good Ridin'
slmjim & Z1BEBE

You are not measuring the negative side of the coils, are you?

While running, the negative side of the coils will have a much lower voltage (around 8 ish). When not running, both sides of the coil should have near battery voltage. (With the black meter lead connected to ground.)

I measured the voltage at the front ( facing forward ) of the coil where the yellow/red stripe wire is connected too.

Then I would start tracing back to see where you lose the voltage. Keeping the black meter lead on the battery's negative post, measure the voltage on the brown wire coming out of the ignition switch. After that measure the voltage on the brown wire going to the kill switch. Then after that, measure the voltage on the yellow/red wire coming out of the kill switch.

If all of those are low, then back track further. Measure the voltage on the white wire going to the ignition switch. If that is low, measure the voltage at the main fuse. If that is low then it's a connection between the battery and main fuse.

These tests are with the ignition and kill switch on as if the bike were running, but the motor is not running. Don't leave the ignition on for too long. If the coils get hot, (not just slightly warm) then turn it off and let it cool.

Loudhvx, I really appreciate the detail on how to check for voltage drop. I have this week off and pull up an electrical diagram and see what I can find.

Finding these voltage drops are sometimes frustrating because it can be a combination of several different drops.
I was using a 77 Kz1000 B diagram, but I think it is pretty similar, if not the same, as a 77 Kz1000 A diagram.

Good luck.