COil voltage question

New to old bikes.....kz650 c-1 (77). Checking the voltage at the coils. Key on engine not running 11.05 on left and 10.92 on right...sound kosher or low? Now for the true newb question....should I check them running or will that blow me across the garage? I know it should still be around 12v but electricity and leaky water scare the shit outa me (smiling clowns too but I have a shotgun for that problem).
Also. Blew a headlamp (sealed Wagner) in about 4 hours. Bought basketcase with a blown headlamp so may have been another undisclosed electrical issue and I'm looking for a tip on where to start.
PO is gonna get a kick in the nuts when I see him.

Thanks in advance for tolerating dumb questions I'm learning!

It wouldn't hurt to clean your connections. Make sure to clean the ground to the engine.

You should have the same voltage at the coils as you have at the battery.

Test your battery voltage then start the bike and run the engine up to 3500 rpm and check the battery voltage. Roy

Cleaning Motorcycle Electrics

Get some of the De-Oxit electrical contact cleaner and figure on spending a good day going from the front of the bike to the back. It’s a plastic safe cleaner/preservative. www.deoxit.com is their website. It can be bought at Radio Shack stores and other electronic supply places.

On the older Kawasaki's, a majority of electrical connectors are inside the headlight housing requiring removal of the headlight, then the fun begins.

Do one set of electrical connectors at a time to avoid mixing up what connects to where. Usually disconnecting, spraying with De-Oxit and reconnecting is about all you'll need.

However, when encountering the green crud of corrosion, a brass wire brush may be needed on the pins you can reach. Some 400-600 grit wet and dry sandpaper strips rolled into a tube should reach the male and female pins in the more difficult to clean connectors.

Smoker’s pipe cleaners, cotton swabs and wooden toothpicks work as cleaning aids.

Really small electrical connectors may require the use of a welders tip cleaning tool assortment.

Most pins in the connectors are coated with a thin plating of tin, and others may be nothing more than copper or brass.

If moisture is added, the resulting corrosion lowers the voltage/current being carried causing dim lights, slow engine cranking, slow turn signal responce and lower input voltage to the ignition coils resulting in weak spark.

The left and right handlebar switch pods will need attention too as they have circuit functions like turn, horn, run/stop, and start.

Usually a spritz or two with actuation of the switch is about all needed for these switches unless corrosion is detected and then careful disassembly is required.

The ignition switch may or may be not sealed to allow spraying the internal contacts. I urge caution if attempting to open this up as springs, and ball bearings may fly out never to be seen again!

If your bike has the older style glass tubed fuses, I suggest replacing them as vibration can cause internal failure. AGX is the type used, and most auto parts stores can get them for you.

Clean the fuse holder clips, looking for signs of overheating(discolored insulation, signs of melting). I use metal polish on a cotton swab, followed by spraying another clean swab with the De-Oxit and then rubbing the inside of the fuse clip.

All battery cables must be clean and tight for maximum current transfer. Check the cables going from the Negative(-) battery terminal/post to the engine mounting bolt

Also the one going from the Positive(+) terminal to the starter solenoid and from there to the starter motor.

If any battery cable feels ”Crunchy” when flexed, replace it as possible corrosion is inside the insulation.

Each "Bullet Connector" will have to be sprayed to ensure good connectivity, especially the ones going to the energizing coil of the starter solenoid.

The alternator output “Bullet Connectors” are usually behind the engine sprocket cover and will need inspecting and cleaning too.

The turn signal light sockets will benefit from a spritz from the contact cleaner along with the tail light/brake light socket.

Some brake light switches can be sprayed on the actuating rod, with the spray running down inside to the electrical contacts, others may be sealed requiring replacement if the switch is intermittent in operation.

Some people put the Di-Electric Grease on cleaned terminations/connectors, I don’t, as I’ve read/heard it can cause problems when it gets hot, actually insulating the connections, so the choice is yours to use or not.

I think I've covered about all of the electrical systems on the bike.........






Why WD-40 Should Not Be Used On Motorcycle Electrical Items.

For many years, I was proponent of the use of WD-40 on fuse clips, fuses, switches and connectors. After hearing of other peoples experience with intermittent and sporadic activity, I shrugged it off as maybe they did something wrong in the application of the product.


It wasn’t until the time I rode my 1982 GPz1100 B2 model to downtown San Diego that I encountered the problems others had gone through.

After concluding my business downtown, I walked to where my bike was parked, turned the key to unlock the forks, and prepared to start the engine. The key was in the "On" position, yet I had no lights in the dash panel, the fuel pump was not running(I have FI), and the horn and tail light were not working.

Puzzled as to why nothing electrical was happening, I remember my earlier conversations about how WD-40 will over time become a non-conductor(more like an insulator). I had some pieces of 400 and 600 grit sandpaper in my tool kit and with them was able to scratch away the coating from the WD-40 on the fuses and clips.

After removing the insulating film, the bike started and ran like it should. Since that time, I’ve told people about the problem with WD-40. If you must use a contact cleaner, I recommend getting some "De-oxit" from Radio Shack Stores or any good electronic supply store.

Of course it is also a good idea to check out the condition of the wires as well. Particularly in the wire bundles. The bundles tend to contain the heat. I have found burned insulation deep in the heart of some of the wrapped wire bundles. These wires should of course be changed out. Especially if the wire has become crispy...

gsnfl wrote: New to old bikes.....kz650 c-1 (77). Checking the voltage at the coils. Key on engine not running 11.05 on left and 10.92 on right...sound kosher or low?

Those readings are fine, you have about a one Volt drop from the battery through the switch, connectors and harness which is normal. Just ride it.

You can check them "running" if you can get under the fuel tank. It will read higher since the system voltage goes up to 14V with engine revving which should pull the coil voltages up to about 13V.