83-85 550 and 750 GPZ's ignition problem

Got spark, looks like there was something wrong around the pickup coils. I wiggled/tapped them, and they started working/reading.

Still a yellow spark, with like 11.8VDC on the coils, maybe time for coils now. Shoot, I've changed everything else.

When I get the bodywork back from paint, I'll see if it will fire, but it wouldn't with the gas that has been in the carb for a couple of weeks.

I guess I may eventually call this a "rebuilding year", and not even run it this year. Bummer.

Thanks for the help so far guys, I will try to keep my chin up and ride this once this year.

Hi.
Im new here but in need of your expertese. I have an GPZ 750 from 85, The problem is that it runs unevenly, at low speeds it has problems accelerating but works better at high speed. After about 10 minutes or so it dies....and wont restart until 15 minutes later after cooling down.

I have changed the ignition coils, and checked the plugs and they seem to work fine. Could it be the pickup coil?
Is there an easy way to test this? Other than with a wolt meter.

very informative thread you bumped there from7 years go
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Tammi wrote: Hi.
Im new here but in need of your expertese. I have an GPZ 750 from 85, The problem is that it runs unevenly, at low speeds it has problems accelerating but works better at high speed.
After about 10 minutes or so it dies....and wont restart until 15 minutes later after cooling down.


are you sure this isn't fuel supply problem? check fuel levels with a clear tube.




I have changed the ignition coils, and checked the plugs and they seem to work fine. Could it be the pickup coil?

change your ht leads and caps 7mm silicon. Unlikely to be the pickup coils


Is there an easy way to test this? Other than with a volt meter
clean up or replace the male coil blade terminals and female connectors under the tank.

Is your tacho working correctly?.

Whats are the blades under the tank? And what is a Tycko? Im from Sweden so my english is not that refined

I did change the ignition coils for two used ones but I suspect that the problem lies elsewhere.

Tacho = tachometer = takometer (google translate)

The blade terminals are on the ignition coils which are under the fuel tank. The wires from the igniter are connected to the blade terminals. Electrical connections become poor from oxidation over time.
Blad terminalerna är på tändspolarna som är under bränsletanken. Ledningarna från tändaren är anslutna till bladuttag. Elanslutning blir fattiga från oxidation över tiden.

The problem may be fuel starvation.
Problemet kan vara bränsle svält.

The problem may be the battery. The battery supplies energy for the ignition coils.
Problemet kan vara batteriet. Batteriet levererar energi till tändspolarna.

I don't know about an alternate way to check the pulsing coil, but you could visually inspect it and make sure the pickups, wires & connector aren't damaged or melted or anything.
Jag vet inte om ett alternativt sätt att kontrollera pulserande spolen, men du kan visuellt inspektera den och se till att de pickups, trådar och kontakten inte är skadade eller smält eller något.

The ignition coils can test fine cold, but they can still be bad when riding the bike. A simple check you can try is to ride the bike at highway speeds if possible, then stop & feel the coils: they should be warm, not hot. press firmly w your fingers. Mine got very hot, so I installed the green Dyna 3.0 ohm coils. The grey 2.2 ohm might be a better match w the stock ignition system.
Tändspolarna kan testa fint kallt, men de kan ändå vara dåligt när man rider cykeln. En enkel kontroll du kan prova är att cykla på motorvägshastigheter om möjligt, sedan stoppa & känner spolarna. De bör vara varm, inte het. tryck hårt w fingrarna. Mine fick mycket varmt.

Tammi wrote: ...After about 10 minutes or so it dies....and wont restart until 15 minutes later after cooling down....

Insufficient valve clearances may cause this.

Would measure valve clearances to determine whether they are within specs.

Good Fortune!

Wow, thank you, you have given me alot to try and test.

Fuel starvation was my first guess but its not that.
The small blades on the back of the coils are clean so that should be fine. The ignition wires for the plugs look new but who knows, only had the bike for a year and the PO bought it and stored it for a year without using it.
Do they use the same cables as a car?
The pickup coil is pritty expensive, even used so I think I´l start by checking the old one.
The translation wasn´t nessesary, I got the text just fine but thanx for the extra effort.

Im no mechanic but I´m not afraid to use my toolbox. Is the top easy to take off and check the valve clearance?

The top end will probably be very different from most KZ's. If it's 4 valves per cylinder, it may have adjustable rockers which are much easier to adjust than the shim setup for KZ's. A service manual will be necessary at this point.

Well, I have the manual for the 900 but it cant be the same as the 750..... I have never adjusted any valves before so it should be exiting.

This video was very informative

The engine looks to be allmost the same.

Usually, measuring the existing clearances with a thickness gauge (feeler gauge) is the easier part -- measure between the cam lobe and bucket (or on large Kaw fours, the shim on top of the bucket) with the cam lobe pointed away from the bucket.

If the clearances are all within specs, can then rule out insufficient valve clearances as a possible issue.

If any clearance is not within spec (usually too tight - insufficient clearance), it becomes necessary to adjust the clearance).

Difficulty of adjusting the clearance varies among different models, depending on the adjustment method.

Screw type adjusters have a screw held in place by a locknut that is used to set the clearance.

Shim type adjusters have either an exposed shim (easier to exchange for another different size shim) or a shim hidden under the bucket which requires loosening of the cam shaft to remove the bucket in order to access the shim.

Must closely follow instructions provided in the Factory Service Manual so as to avoid bending a valve.

Good Fortune!