ZX11 starter and alternator problem

Firstly I should say I am not certain that the starter circuit and alternator problems are linked.

The alternator problem is the regulator has failed twice in 12months (of infrequent use). The battery at the time was old and is now no longer accepting a charge and has been replaced.

The starter circuit problem is intermittent failure to operate (usually when I am a long way from home). When the starter button is pressed there is a 'click' at the relay in the Junction Box but nothing else. I thought the problem was the relay and replaced the Junction Box but that did not resolve the problem. I also found faulty wiring at the steering headstock, the wires to the ignition switch had all been cut and poorly rejoined. These wires have also been replaced and the soldered connections to the back of the ignition switch done properly while I was at it.

There was some improvement and the problem is less frequent but still occurs. Remarkably, jiggling the wires near the junction box connectors, or a combination of jiggling and un-plugging and plugging-in of the connectors can make the starter work.

I am at a loss to know how to trace this fault and all suggestions will be welcome.

Starter Solenoid/Motor Checkout Procedure

Some simple steps to determine what is working and what's not:

1.Fully charge and test the battery(most bike shops can load test the battery, and then use a floating ball hydrometer to check specific gravity in the charged cells).

2.Clean all battery terminals of corrosion.

3.Tighten all starting related connections(Positive RED(+) battery terminal, Negative BLACK(-)terminal) and from the terminal to the engine case. All connections must be clean and tight. If the cables feel “Crunchy” when flexed, they may have corrosion inside the insulation, requiring replacement.

4.Clean the cable from the starter solenoid to the starter motor.

5.Clean and check the "bullet connectors" going to the coil side of the starter solenoid.

6.Try again to start the bike, keep in mind some Kawasaki’s have a clutch interlock to prevent cranking the engine while it’s in gear, so the clutch lever must be squeezed.

7.If no luck, go to step #8

8.Wearing eye protection, bridge with pliers or a screwdriver the two heavy duty(large)terminals on the solenoid. If the bike cranks, your solenoid may be bad.

9. If the starter won’t turn over, one of several things has happened; The starter motor has seized due to brushes binding up, lack of lubrication in the bushings of the motor, the battery is weak , the engine has seized or it could be a combination of any of the above. A website for starter motors is:

A. www.psep.biz/store/mitsuba_starter_motors_page_2.htm

B. www.nationsautoelectric.com/Kawasaki.html

C. www.whitedogbikes.com/cat--Kawasaki-Star...-Starter-Motors.html

D. www.ricksmotorsportelectrics.com/starters.php

E. www.dbelectrical.com/

10.The dealer may want $$$ for a new solenoid, but take your old one along and visit the nearest riding lawn mower shop. They have solenoids for about $15 that with a little work will fit. Be aware that the new solenoid from the lawn mower shop may require a ground wire for it to work.

11. I’d recommend upgrading from the existing battery cables to at least 6 gauge welding cables.
They are available in two colors(RED and BLACK) have more flexibility due to being constructed with finer conductors, and will fit in tighter areas.

12. The welding cable is sold by the foot, so take careful measurements or bring your old cables along. Most battery shops might be able to supply the cable too, so call to find out. The battery shop should be able to crimp/swage on the end of the welding cable the terminal ends or lugs using either a dedicated crimping machine or a tool that looks like a bolt cutter that has special dies to terminate the cable.

The website www.electrosport.com has a page dedicated to alternator & battery checkout, and they also sell regulator/rectifier units.

Moving the wires by flexing/jiggling may indicate broken conductors or dirty connector contacts. Try this before replacing parts:

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. Or use any plastic safe electrical contact cleaner(NOT WD-40 !).

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.

Which model do you have?

ZX11 90-2001 liquid cooled four, ZX1100C and ZX1100D

83-84 GPz1100 - ZX1100A1 and ZX1100A2 air cooled four

95-97 GPz1100 ZX1100E and ZX1100F liquid cooled four

There was also 1981-82 GPz1100, KZ1100B1 and KZ1100B2 air cooled four

Can get confusing

Thanks for the replies

My bike is a ZX11 D5 1997, California model sold new here in Brazil.

I have now unwrapped the wiring loom adjacent to the battery, junction box, starter solenoid. I sprayed contact cleaner into some manufacturer installed, crimped, wire duplication splices and ran solder into them for good measure before re-insulating.

Now I am waiting for a replacement alternator regulator (parts are difficult to find and expensive here) before I put that back together and try the starter circuit again.

I bought a brand new 1991 ZX11 in 1990. After a year the starter started working intermitently. When the bike was hot, as in your long rides, it would not start. The problem was the press fit of the gear onto the shaft of the starter, when hot and expanded, it would slip. Kawasaki bought the motorcycle back from me in May of 1992 because they would have taken 3 months to get the part and they did not want me to lemon law the bike. I hope that this is not your problem.

Hi MFolks
Thanks for your reply. The subject heading of my original question was a bit misleading as I couldn't fit 'starter circuit' and charging circuit' in teh box. Still, that doesn't reduce the relavance of your response, thank you.

I am particularly interested in what happens to wires inside their plastic insulation. This is because I have checked all the components,
Junction Box - replaced but Relays, diodes, fuses and contacts all re-checked,
Solenoid - dismantled, internal & external contacts cleaned
Ignition switch - wiring to loom connector replaced (sad story), dismantled & internal contacts cleaned
Handlebar switches - dismantled & internal contacts cleaned
Fuel pump - initially cleaned contacts then replaced unit
Connectors - all dismantled and cleaned much as you describe in your response
Loom - tape removed from most of its length, inspected (no damage found) and re-taped, local to Junction Box wire duplication crimped connectors cleaned and soldered.

Having done all this, except the crimp soldering, a second replacement alternator regulator seems to have burnt out (I am not very confident of my ability with a digital multimeter so will not be sure until I fit another new one); the voltage measured at the battery with the engine running starts at 12.5V then slowly counts down, and still sometimes when I press the starter button all I get is a click at the Junction Box relay.

So, any pointers you can give me as to what may be happening inside the wiring insulation will be gratefully received as I am almost at a loss here