Hot-Start issue

I'm having some problems with a hot-start issue. '82 KZ1100A2. When the engine is at full operating temp, for example, riding for awhile and then stopping and shutting down the motor; If I let it sit 5 mins, it'll fire right back up. If I let it sit 2 hours, it'll fire right back up. But, if I let it sit 1/2 hour, I have to crank the throttle open while cranking to get it to start.

Everything's been done on this machine, from valve clearances and shim replacement, carbs rebuilt, float levels done, and synchronization, you name it, I did it. New battery, too. Only thing I didn't change out were the spark plugs and wires, they looked fine and the thing runs like a scalded dog. Compression check excellent, etc. etc.

I mean, it starts and everything, but it shouldn't require near WOT when hot to fire up.

Starter spins freely, and quickly.

Thoughts?

Thanks.

Tom in Florida

I'm thinking your ignition coils are being affected by heat, once they cool down, they will produce a spark. Try this, once your home, check for spark with the tank off and the coils heated with a hair dryer(simulating trapped engine heat).

Also the sparkplug caps have resistors that fail from heat & vibration, they should test to 5000 ohms by unscrewing from the sparkplug wires.

You should test the pick up coils too:

Ohm Checking Pickup(Pulsing) Coils

The pickup(Pulsing) coils on the Kawasaki’s with the factory supplied electronic ignition can sometimes fail or become intermittent due to heat and vibration.

1.Trace back from where the pick up coils are mounted,(BEHIND A RIGHT SIDE, CD SIZED COVER) locate and disconnect a small 4 pin connector. Using a multi-meter set on OHMS and range of 2K, check between the BLUE and BLACK wires(#1 and #4 sparkplug wires) for between 360- 540 OHMS.

2.For #2 and #3 sparkplugs the wire colors will be YELLOW and RED, again 360-540 OHMS. The 550’s,650’s & 750’s may be backwards to the Z1’s,Kz900’s,Kz1000’s & Kz1100’s.

3.If the pickup coils are suspect of failing due to heat, they can be stressed using a hair dryer without the need of the engine running.

4.A replacement set of pickup coils might be obtained from a dealer who serviced the police Kawasaki’s.

5. If replacement pickup coils are not available, your next choice would be to order a Dyna “S” electronic ignition system from www.z1enterprises.com It replaces the IC igniter with a smaller module located where the mechanical ignition advancer was mounted.

6. Checking with Kawasaki.com website has determined that the Pick up(pulsing) coils are available . The pulsing coil # is 59026-1133 and replaces the older # 1002, 1012 which were used from the MKII motors until the 2005 P24.

7.Check the small 4 pin connector that the pickup coils connect to for corrosion/loose pins too.


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.


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. 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.

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.........

“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

Coil would be the first thing I suspect. If electronic ignition, might be the igniter module.

Do you see any flooding from the carb tubes?

No flooding at the carbs at all. I would wager it's probably a voltage drop too, I was thinking that, just wanted some reinforcing positions. I've got to yank the tank again and the carbs (gonna put in that manual cam chain tensioner, it's being shipped now). While off, I'll meter up the nominal coil voltage. Already did a bunch of connectors as far as cleaning, etc. and the fuse block. Ought to just shot-gun replace that block anyway, with an ATO version, at least.

Thanks for the input.