TOPIC:

I have a 1982 GPZ750R with 9,900 miles, I live near Fresno ca and rode it to work in 98 degree weather, recently after 10 min of riding th engine starts to jerk and studder then tries shut down and I hear a oddclicking or tapping in the left rear exhaust area ? Anyone have any idea if the coils would do this ? Or what the heck would cause this ? If i let it cool down it restarts.

Sounds like coils.
Steve

What mods if any and have you don't all the maintenance as listed in the service manual? With only 10k miles I doubt the problem is the coils.

Thanks

I'm still not sure what the problem is on this, it dies out after a few minutes of running, it could be my stator, it starts at 12.57 volts, not running, then when started it dropped to 12.33 volts, as it ran it slowly climmed up in voltage, went to 1240, 12.55, 12.64, 12.78 then to 12.88 in voltage with it running warming up. It then started to die on me so I shut it off. The coils previously measured 350 RPMs on one side and only 650 RPMs on the other side while running. My plan is to buy a new coil, see if that fixes it, if not install new stator to see if the charge and electrical stabilizes, and maybe a new regulator. I was hoping to single out which one first before buying all three. Any ideas anyone let me know.

This replacing bits until it is fixed approach gets expensive fast. Improve on your diagnostics, this is just as likely a wiring or connector fault.

An analogue meter gives more consistent running voltage readings as digi meters can pick up interference, causing the reading to go all over the place.

The factory Kawasaki service manual specifies various charging system tests so you may want to review. For example, to judge charging system voltage it's necessary to rev up the engine to 4000 rpm's or more, and then read the DC voltage. A properly functioning charging system will output 14+ VDC at that rpm.

Regarding coils, they are highly reliable and rarely fail. I believe people blame them for faulty spark issues far more often than truly deserved.

Tyrell Corp wrote: This replacing bits until it is fixed approach gets expensive fast. Improve on your diagnostics, this is just as likely a wiring or connector fault.

An analogue meter gives more consistent running voltage readings as digi meters can pick up interference, causing the reading to go all over the place.

Amen!! If you don't have one I highly recommend you buy the Kawasaki Service Manual for your exact year / model bike and run the diagnostics for each of the charging system / electrical components. Otherwise you could spend $1,000 hoping to stumble on the solution and still not improve anything. Think of yourself as a doctor trying to help a patient. No heart transplants, liver transplants, etc. until you have positively identified the source of the problem. Ed

To me, the strange part is that the battery has enough power to start the bike, but gets too weak to power the ignition in just a few minutes.

Clearly there is a charging issue if you can't get higher voltage by revving, but there could be something else involved.

Dyna S ignitions were reported to be voltage sensitive, but you shouldn't be running the Dyna S with stock coils from that bike.

Todd wrote: ...The coils previously measured 350 RPMs on one side and only 650 RPMs on the other side while running. ...

Do you mean ohms? And you can't check that while running. Or are you measuring RPM for some reason?

Either way, the manual will go a long way to helping you solve the problem. But in your situation right now, it will be difficult since it may be two problems and it won't run long enough to do a diagnosis.

Can you confirm that the ignition is completely stock and original?

Also, have you made any changes or done any repairs recently, like adding a fuel filter?

I changed the fuel filter but changed it back to the original and it seems the same. I did mean Ohms not rpms on the coil but it sounds like i need that manuel, Is ebay the best place to buy that ? Thanks.

eBay is an excellent source for the Kawasaki Service Manuals. Just be sure to get one that covers your bike's exact year & model as there are differences between models. The models covered are normally listed on the back cover of the manual. Ed