Plug Issue and Miss Issue

I have a 1976 Kz900 that I am having a couple of issues with. I have a miss between 2800 and 3100 rpm. I am also having a problem with the #2 plug. Sometimes when I start the bike, it does not run rigth and the #2 pipe is not hot. I pull the plug wire and change the plug and it then runs good. A day or two later, I have the same problem and put the other plug back in and it runs good again. Anyone have any clues on these issues ? Thanks.

I'd change all 4 sparkplug caps, as they have a 5000 ohm, non servicable resistor for RFI (electrical noise) supression. Also try another brand of sparkplug than NGK. They seem to be having quality problems, as other forums are reporting failure with this brand of sparkplug.

Try a new set of Bosch,Accel or Champion plugs before doing any carb adjustments.
Checked the input voltage to the ignition coils?

Testing Kawasaki Ignition Coils For Input Voltage

When voltage testing Kawasaki Ignition Coils, the following needs to be done:

1. Remove the fuel/gas tank to access the coils.

2. Fully charge the battery.

3. Using a multimeter, set it up for VDC(Volts, Direct Current), range of 20.

4. Turn on the ignition switch and the run/stop switch to “Run”.

5. Put the multimeter’s RED probe on where the red or red/yellow wire goes on the ignition coil.

6. Put the multimeter’s BLACK probe on either the battery Negative(-) post/terminal or a good frame ground.

7. You should be able to see battery voltage at the ignition coil connection, but this depends on the current draw of other items in the same circuit.

8. If the tested voltage is down to 8-9 volts, you probably need to clean the many and various electrical connectors.

9. To check the spark output at the sparkplugs, use these:

Ignition Spark Testers
www.lislecorp.com/divisions/products/?pr...ivision=1&category=8
www.lislecorp.com/divisions/products/?pr...ivision=1&category=8
(Using the Thexton 404 Spark tester)


Instead of grounding the sparkplug with the sparkplug wire attached, looking for a spark. This method puts the IC Igniter and ignition coils at risk of failure due to high currents, and possible internal shorting.

Cleaning Motorcycle Electrics

1. 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 purchased at most Radio Shack Stores or any electronic supply places. Or use any plastic safe electrical contact cleaner(NOT WD-40 !).

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

3. 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.

4. 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.

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

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

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

8. 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.

9. The left and right handlebar switch pods will need attention too as they have circuit functions like turn, horn, run/stop, and start. The older Kawasaki’s have reports of the soldered connections crumbling, if your bike has this problem, just ask, as I’ve got a repair procedure for this.

10. 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.

11. 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!

12. 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, along with boating supply stores.

13. 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.

14. 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

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

16. If any battery cable feels ”Crunchy” when flexed, replace it as possible corrosion is inside the insulation. Inspect all heavy duty battery cables and the smaller wire terminations(Bullet Connectors), for failed crimps, and those used in the electrical connectors, as they can fail over time.

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

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

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

21. 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.

22. 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.........

“I spent a weekend going through every electrical connection and switch on the bike with a little scotchbrite pad and DeOxit - what a difference! Everything was brighter, gauge backlights, indicator lights, turn signals, I was getting a nicer spark, it fired up quicker, etc. Well worth my time. WELL worth it! “

From a forum member at www.kzrider.com

+1 on the plug caps and NGK plugs. We see a lot of NGK plug failures at my buddy's shop. When you change the plug caps snip about 1/8" of the end of the plug wires to get some fresh clean wire to screw the caps into.

BIGKEVIN wrote: I pull the plug wire and change the plug and it then runs good. A day or two later, I have the same problem and put the other plug back in and it runs good again. Anyone have any clues on these issues ? Thanks.

What color is the plug? Sounds like you might be fouling it.

Agree with changing out any old electrics like caps and wires, especially if the coils are old ones (kick em)

I don't think that it is the plug wires. I installed new Accell coils and wires. I am getting battery voltage to the coils after doing the wiredgeorge relay wiring. I may just get 4 new plugs, not NGK and see what happens. I will also go through the wiring and clean the connections.

Would perform the clear tube test on #2 carb, and assure fuel level is within specs.

Good Fortune!

I jus put 4 Champion plugs in the bike and just received the clear tube piece from Z1. I am going to check the fuel level on all 4 carbs. Do I need to remove the each time to check the fuel level ? Or what is the best way to check it ?

Clear tube test can be done with carbs mounted--

www.kzrider.com/forum/3-carburetor/55602...t-engine-isnt#556366

BIGKEVIN wrote: I don't think that it is the plug wires. I installed new Accell coils and wires. I am getting battery voltage to the coils after doing the wiredgeorge relay wiring. I may just get 4 new plugs, not NGK and see what happens. I will also go through the wiring and clean the connections.

I've had an Accel Coil Wire Fail, with very similar symptoms. They are not a solid core, and can give it up from the vibration, and tight bends on a bike. Check each wire with a OHM meter, and you may find the issue.

I took the carbs of the bike and I tried checking the float levels for the first time. #1 was high and #2 and #4 were low. I had the clear tube from Z1 and thought that I had adjusted all of the carbs correclty. I put everything back together and turned the fuel on from the tank and fuel started running out of the overflow tube between the #1 and #2 carbs. I guess the levels are not set correctly or fuel won't be running out of the tube. Since I have the carbs back on the bike, I am going to check the level as best as I can without a center stand and see which carb is not set correclty and then take the carbs back off the bike to set the float again. Can the floats be removed with the carbs on the bike ?

BIGKEVIN wrote: ...fuel started running out of the overflow tube between the #1 and #2 carbs....

If it's a stock configuration, there should be four separate overflow hoses, each being attached to an overflow nipple at the bottom of each float bowl.

Hopefully not confusing vent hoses as overflow hoses.

Good Fortune!