won't stay running

Names Garrett.
I have a 1979 kz650, I bought it a year ago, 14,000 miles on it. Since then I've put 6,000 miles on it not a problem, even after wrecking a couple times.
I recently upgraded from points ignition to electronic, worked fine for a week, then out of the blue the bike would not stay running. It would start then die out then wouldn't start for a while. Then repeat the process. The battery I believe is drained again. Did I fry the regulator? Do I need to upgrade the regulator and battery? Any idea on whats wrong?

I would charge the battery and temporarily put the points back in. If the problem goes away there's something wrong with the electronic ignition. Regarding the regulator; take a look in your Kawasaki Service Manual. There you will find the test procedure to see if it is operating properly. Ed

Possibly fuel starvation.

Could disconnect the fuel line from the petcock, and allow fuel to drain into a container to determine whether ample fuel is continuously flowing through the petcock.

If there's blockage for whatever reason inside the petcock, the petcock may be allowing just enough fuel to slowly fill the float bowl while the engine isn't running, which would allow initial crank-up and running until the float bowl empties (fuel starvation).

A clogged petcock is only one of several reasons that might cause fuel starvation. Other reasons may include such things as kinked or obstructed fuel line, clogged float valve filter (if so fitted), etc.

Good Fortune!

The bikes that seem to have the most problems with the Dyna S are the KZ650's with single-phase charging sytems. That would be the 78 and 79 KZ650's, (and maybe some 1980?).

That doesn't mean all 78 and 79 KZ650's will have the problem. But when the problem shows up, it's often those bikes. The Dyna S is very wasteful on power, especially at idle. Apparently there must have been some 78/79 KZ650's with weaker charging systems, but the problem doesn't show up until a Dyna S is installed. (The factory electronic ignition is very efficient, and won't cause this problem.)

Are you using a Dyna S? If so, there's likely nothing wrong with it. It's just exposing a weaker charging system.

If you have a multimeter(or have friend do it for you), create access to the bikes battery, start the engine, and with the mutimeter set on VDC(Volts, Direct Current), range of 20, put the RED probe from the meter on the positive battery post, or terminal, and the BLACK probe on either a good frame ground, or battery Negative post or terminal, and see if the charging systems working. If it's weak, you might see 10 volts or less. but if it's good. the maximum will be 14.5 volts D.C Post back with your results.

When the motor starts and runs, how long does it stay running before it dies?

Good Fortune!

first time it happened, brand new battery, ran it 40 miles everyday to work. on the saturday i warmed her up, took her around the block because i forgot something, let her sit while i went inside. when i got to the light down the street it died. electric starter sounded like it was losing power. kicked it a couple times, it started. made it to the next light started making a slow turn gave it gas, died mid turn, didn't pull the clutch before it dumped me. after that it wouldn't start, probably cause i flooded it and the battery. let it sit, started then it died when i gave it throttle.

i need to get a new battery before anything. ill keep y'all posted when i get it and take the multimeter to it.

thank you all for your help.

Yep, for these engines to run, you'll need air, fuel, spark, compression & good sparkplugs(how's your look?) If BLACK, it's too rich. WHITE, is too lean, but a light tan ,just about right. Seen on the sparkplug center electrode.

Okay, i got a new battery, put my points back in. It ran for a bit the died again. I put the meter to it. Key off, high 15 and higher. Key on 15 and higher. Bike running, high 14. ??

With the engine running the voltage should be between 14 and 15 volts with a maximum close to 15 volts at 4000 rpm or higher. So it sounds like the charging system is working properly if you're seeing 14+v but less than 15v with engine running. Ed

@ 40 miles then dies.... Battery not being charged during running operations....

Check charging circuit/feeds back to battery.

Also verify rectifier/regulator is ideally grounded.....
If to frame, then confirm frame is grounded or relocate the R/R ground wire to battery (-) terminal.

Had this happen on a Suzuki 30 years ago I rebuilt.... Frame paint on ground terminal...DOH! :pinch:

In case you need

If you have the type of run/kill switch that has them consolidated into a single switch, check to make sure the "run" contact is clean. I had this exact problem on my ;'83 KZ1000 and it was a dirty run switch.

When the switch is in the 'start' position, it uses a different contact to power the coils than you use during the 'run' phase. As soon as you let go off the starter, it's as if the 'kill' setting is on.