79 KZ650 Loss of Power, Engine Quits

Okay, I'm convinced. I will definitely investigate this. Thanks Freak.

A simple test for the coils is to ride the bike at highway speeds, then stop & feel them to see if they are getting hot to the touch. press hard with your fingers. They should be warm, not hot.

Another possibility is the battery. Use a good battery charger & make sure the battery holds a charge. After charging it should have at least 12.6 volts. I use a Ctek US 0.8 charger & test the battery w a VC97 digital multimeter.

martin_csr wrote: A simple test for the coils is to ride the bike at highway speeds, then stop & feel them to see if they are getting hot to the touch.

I would happily try that if I could get the bike to run that long!

The battery is new this season - I'll check the voltage though.

Thanks Martin.

Are valve clearances within specs?

Good Fortune!

Hey Patton. The valves were adjusted last Spring and the bike has only a couple thousand new miles since then. I think they should be in good shape.

Could test for cap venting issue with bike parked and engine not running.

With fuel tank cap closed, does fuel drain freely and continuously from the petcock into a catch pan?
Does opening the cap make any difference in volume of flow through the petcock into the catch pan?

Good Fortune!

PGS wrote: I have not tested the coils as suggested in that thread. I will do that the next time the tank is off but it seems like a long shot to me..

If it is the coil(s), they will bench test OK and you will keep chasing your tail. Bad coils start arcing down after the coil gets hot and so bench testing won't catch it. You also won't have a HIPOT tester that can put enough high voltage on the windings to see the breakdown point.

30 year old coils need to get punted.

Good point. That logical fact slipped my mind. I should have thought of it when I was talking about the coils and mentioned it. I never tested mine, just replaced them. Makes sense that bench testing would do nothing though.

bountyhunter wrote:

PGS wrote: I have not tested the coils as suggested in that thread. I will do that the next time the tank is off but it seems like a long shot to me..

If it is the coil(s), they will bench test OK and you will keep chasing your tail. Bad coils start arcing down after the coil gets hot and so bench testing won't catch it. You also won't have a HIPOT tester that can put enough high voltage on the windings to see the breakdown point.

30 year old coils need to get punted.

I know this is NOT a Councours 1000, but there have been reports of fuel starvation time after time after a fuel filter has been installed. The brand or type doesn't matter the fuel just won't flow properly. I would start there.

It never hurts to check the carb bowls for gunk. If there was gunk in the tank, I bet there is gunk in the bowls.

Regards, Z1 driver.....

Regarding the fuel cap, a test ride with the cap open did not show any improvement.

Regarding the fuel filter, these symptoms appeared before I replaced the filter & lines - that was the reason I started replacing things.

It looks like I am down to replacing the ignition coils and cleaning the carbs.

Thanks to all for the continued help with this.

Can anyone tell me where I might get ignition coils for this bike? I have looked at a few web sites and I see "out-of-stock", "obsolete", and such.

Assuming you have a KZ650-B3: www.z1enterprises.com/ShopByCategory.asp...egory=01010103020407

I think the engine is almost exactly the same on the C3 so these coils should work for whatever 79 KZ650 you have.

PGS wrote: Can anyone tell me where I might get ignition coils for this bike? I have looked at a few web sites and I see "out-of-stock", "obsolete", and such.