kz750 / kz400 Coil bad? Replacement options?

I have a 1979 kz750 and a 1976 kz400 and both are turning over, have gas, cleaned carbs but drive a bit weakly and then die. Seems like there could be a coil issue for both.

I saw a few videos on youtube showing how to test the ohm's on the coil. What is the best way to test the coils and deduce what's wrong?

Also, if I was going to replace the coils, would the Dyna 5 ohm coils Z1 sells be a good choice or should I go OEM?

www.z1enterprises.com/product/DYDC8-1-single

Thanks for any info!

Dyna's are good coils. I have no complaints with mine. If you have points 5 OHM is OK.
Steve

The dyna 5 ohm is good if you for sure sticking with points. If you do, try to make sure the dwell angle is near the long end of the range... like 195 degrees. That means the points are closed a little more than half of a crank rotation.

Otherwise, there are 4-ohm options that look like the stock coils. I usually see them on ebay etc.

If you might go with electronic ignition in the future, then the Dyna 3 ohm may be a good choice in the interim. If you go with them, make sure the dwell is just a little under 180 degrees. That means the points are closed a tiny bit less than half of a crank rotation.

I have 4 OHM. I can change lanes if I want to. :lol:
Steve

Thanks for the reply!

Would those ebay 4ohm's be a good quick fix just to get running? Not doing a full restore at this point, just getting some bikes ready for new riders.

All I can say is you'll rule out one possibility. Coils get old and can fail in many ways.
Steve

Oldercrow wrote: Thanks for the reply!

Would those ebay 4ohm's be a good quick fix just to get running? Not doing a full restore at this point, just getting some bikes ready for new riders.

It may be quick and cheap, but it may also be a permanent fix, for a few decades.

Make sure the listing says 4 ohms, or ask the seller. The 2.4 ohm coils look similar, but they will burn up the points.

They are the black ones that look like the stock coils (some of the stock coils were different color, though). The only issue is the mounting bolt spacing. If that's not listed, ask the seller. There are a few different spacings among Kz's, so you'll want to measure the old ones.

Can running a 5 ohm hurt anything?

Oldercrow wrote: Can running a 5 ohm hurt anything?

Won't hurt a thing.

No eBay APP ID and/or Cert ID defined in Kunena configuration

Oldercrow wrote: I have a 1979 kz750 and a 1976 kz400 and both are turning over, have gas, cleaned carbs but drive a bit weakly and then die. Seems like there could be a coil issue for both.

I saw a few videos on youtube showing how to test the ohm's on the coil. What is the best way to test the coils and deduce what's wrong?

Also, if I was going to replace the coils, would the Dyna 5 ohm coils Z1 sells be a good choice or should I go OEM?

www.z1enterprises.com/product/DYDC8-1-single

Thanks for any info!

Here is one that should work:

I got these from Z1 plus new wires.

www.z1enterprises.com/product/DYDC8-1

Oldercrow wrote: I have a 1979 kz750 and a 1976 kz400 and both are turning over, have gas, cleaned carbs but drive a bit weakly and then die. Seems like there could be a coil issue for both.

I saw a few videos on youtube showing how to test the ohm's on the coil. What is the best way to test the coils and deduce what's wrong?

Replace. You don't have the equipment required to test a coil.