1976 kz900 coil replacement

I have a 1976 kz900A-4 that i have been trying to get back on the road and while troubleshooting some carb problems noticed the #1 cyclinder appeared to firing intermittently? Double checked my theory by squirting my #2 exhast pipe with some water and it barely steam as compared to my other cyclinders. Did a ohm check on the spark plug wire and it checks good. Figured i would swap my (#1&4)Accel coil with an old stock one that i had changed out 20 years ago. Anyone know how the heck to hook this thing up! My accel coil has terminals to hook my wires to but the stock one has some nuts and terminals in the parts bag without a place to hook them up to? Checked my shop manual and doesn't show a good diagram

gman911 wrote:

...Figured i would swap my (#1&4)Accel coil with an old stock one....

Might consider just swapping existing Accel coils to see whether or not the issue follows the suspected coil.

That has definitely been an option but i still would like to know how these are suppose to be installed just in case i might have to reinstall them and if for nothing else but muy own curiosity.

There's a red/yellow wire underneath the fuel tank that provides battery voltage to the coils via a dual connector which runs a red/yellow wire to each coil.

Each coil has two terminals for the primary windings. The red/yellow wire goes to either coil terminal (it doesn't matter which terminal -- just use the easiest to reach).

The other coil terminal connects to a trigger wire from the ignition (points or Dyna-S or whatever). A black wire from the left side of ignition triggers the left 1/4 coil. A green wire from the right side of ignition triggers the right 2/3 coil.

Hope this covers some of the info desired.

Thanks for the info and here is a picture (attachment) of what the old coil looks like. It's confusing cause i don't see a place to attach the wires. Any ideas?

here is what the current one looks like

Just for reference, I thought (1) Dyna coil was green and bolted on to existing stock frame tabs, and (2) that accel coils were yellow and mounted via hose clamps to a fitting mounted to the stock frame tabs.

Here's a pic of the two brands as I know about them, so there may be other versions.

accel vs dyna

In your pic, the coil is green and appears mounted directly to the stock frame mount (but only a single plug wire input is visible). Accel coil has plug wires from the sides (instead of the ends like Dyna), so am wondering if yours are actually Dyna coils or maybe an older version of Accel coils.

The black "stock" coil pictured appears to have had the "permanently mounted" plug wires pulled loose (which I've had no experience in re-attaching, although reattachment is probably possible).

On your green coil pic, are we possibly seeing a right hand Dyna coil?

Maybe the misfiring is not a coil problem. Have ohm readings been done on both primary and secondary windings on both coils?

May be defective plug wire and/or plug caps. What's the situation with those items?

Has the test been done for leaking plug wires/caps by spraying with water mist in dark garage with engine running?

What is the voltage reading on the red/yellow wire to the coils with engine at idle speed? At 4000 rpm?

Forgive all the questions and suppositions. Just trying to help you zero in on the mis-firing problem.

Post edited by: Patton, at: 2007/09/06 19:29

Thanks for answering, and there are never too many questions.
My coils look like the dyna type and has two plug wire input. Sorry on the pic but i was more concern about showing the location of the wires coming from the points and how the old ones didn't have any place to connect wires. Hard wired? Well that explains the lack of any kind of normal connection. I guess i can rig something if it comes to that. The coil in the pic is the left side (#1 and 4 ) if you were sitting on the bike. I'll go ahead and recheck the readings on the primary and seconday windings and do a spray mist check. Thanks again for your help

gman911 wrote:

...here is a picture (attachment) of what the old coil looks like...don't see a place to attach the wires....

The two terminals shown on stock (oem) black coil are to the primary windings. Connections here are by soldering. One terminal connects to the red/yellow wire (same for both coils). The other terminal on the right side 2/3 coil connects to the green ignition trigger wire. The other terminal on the left side 1/4 coil connects to the black ignition trigger wire.

At the other end of the stock black coil (not shown in the pic) is where the two permanently attached plug wires are fitted into the oem coil (the secondary winding).

The earlier pictured green coil has screw-on connectors for wiring to the primary terminals, and removable style connections for the plug wires.

A plug wire splicer is available for connecting new plug wires onto the stock coil.

As a practical matter, absent further info, I would suggest continue using the green coils (if primary and secondary windings pass the ohm test). If new plug wires are needed, would suggest the relatively inexpensive Dyna 7mm solid core version which come with the caps already attached and in place.

splicer

plug wires

Good Luck with repairs.