Eliminate ballast resistor?

How much current allowable in primary windings of ignition coils?

The Martek coils have 2.3 ohms resistance. Note I phooked up and used 2.4 ohms for below calcs. 

No big deal.

So it's

• ~6 amps with out ballast resistor
• ~ 3.6 amps with ballast resistor

I wonder what  nominal is?

Coil only - about right, current-wise. See post below this one...

With ballast resistor - to little current = weak spark?

Q:  Can anyone tell me which color wires feed which coils for the relevant cylinders?

A:  #1 & 6 - Black,  #3 & 4 - Blue,  #2 & 5 - Green

Q:  What are the symptoms of bad ignition coils and what are my options for changing out my original coils?
A:  At some point in time, the original coils start getting cracks in them and go bad.  I've seen this happen on these 1300's as early as only 7000 miles!  It's not the best way to go, but you can bolt on the coils from the slightly newer Kawasaki's (80' - 85') with the removable leads and a primary resistance of 2.5 ohms in the same holes as the old ones. 

These coils were used from 1982 to about 1989.   The important thing to remember is that you remove the ballast resistor (if so equipped) so the total resistance to the CDI box is correct when installing the 2.5 ohm coils.  Otherwise you’ll have problems with the primary resistance being too high.  The original coils have a primary resistance of 1.5 ohms, and in conjunction with the 1.2 ohm ballast, the CDI sees 2.7+ ohms or a little more.  

If the ballast goes bad and shorts out as it sometimes does with the original coils, the CDI would quickly burn up since the original coils are 1.5 ohms.  Alternatively, if you use the ballast on the newer 2.5 ohm coils, the primary resistance will be 3.7+ ohms and that could damage the CDI also.  The 2.5 ohm coils are a bolt on replacement for your old coils and as a bonus, they sport replaceable wires. 

On the original coils, you couldn’t replace just the wires as the wires are made into the coils.  You will have to make up some wires to power them up with because of the different connectors, but this is a simple task.  To by pass the ballast, connect the one yellow wire which is the power in, to all 3 pink wires which is power out to each coil.  You can solder them all together which is best or use whatever means you must to make the connection, as long as it's a good connection.

Whatever you do with the coils the total resistance at the end of the day must be same as what you started out with.  If your total resistance (coils + ballast resistor) is 2.5 ohm then you should replace with 2.5 ohm coils and bypass the ballast resistor (which is approximately 1.7 Ohm and plenty WATTS).  The reason this gives better spark is that you lose almost half your voltage in the ballast resistor!  Replacing it with a 2.5 ohm coil means the coil get all the voltage your CDI is putting out and gives better spark.  The CDI is expecting approximately 2.7 to 3.0 ohms so make sure it doesn't change.
 
: some calcs : 12v and 2.5ohm = 4.8 amps (Normal)
: 12v and 3.5ohm = 3.4 amps (weak spark)
: 12v and 1.5ohm = 8 amps = fried CDI unit, but good spark while it lasts ;-)

The last example is what you get when you use stock coils, but remove the ballast resistor or the resistor goes bad.  It gives almost double the amps that the CDI is made for, and although it won't let the magic smoke out immediately it will soon.

The reason we can use 2.5 to 3.0 ohm coils safely, without knowing what a schematic for the inside of the CDI may look like is that we haven't really altered anything.  If we study the maintenance section of our beloved Kawasaki service manual, we will discover that their is some variance listed, but the ballast resistor has a resistance of approximately 1.3 to 1.7 ohms.  Stock coils have a primary resistance of approximately 1.3. to 1.7 ohms for a total of 2.6 to 3.4 ohms, but we'd like to be at the lower range, not the higher to get the best spark output.

There really is no risk because that CDI is still reacting to the same resistance it always has and doesn't really care whether it comes from a combination of resistors and coils or just one coil.  I cannot say for certain what may happen with a 3+ ohm coil, but suffice it to say the higher you get the less spark output.  Your other options are to buy aftermarket coils from Dyna, Nology coils, or some other high performance coil with the appropriate ohm rating.  The Accel coils are much more costly at about $80 to $120 apiece; the Dyna’s about $70 each, Nology's about $75+ each (posted prices on the net as of Nov/2004).  You can check the Accel installation page for more info at -  http://accel.zn1300.com/  

Update!  Until 2005 I didn't have any problems with Accel coils, but read the Accel page for current info about Accel's ohm readings measuring too high!  Not a good coil for us anymore in my opinion!

Q:  What is the replacement Accel coil part numbers for the 1980 KZ1300B2?
A:  Accel part #'s are 140403 (2 coils) & 140403S (Single coil).  The same coil for all year model KZ1300, Z1300, ZN1300, ZG1300 and Voyager 1300's.  All year 1300's use the same Accel coil.  On the older bikes (83' KZ1300's or older) with the original 1.5 ohm coils and ballast resistor, you simply pull the ballast off, toss it in the trash and install the coils without a ballast.  On the newer year model bikes that came with 2.5 ohm coils and without the ballast, you simply mount the coils and ride.

From Kz1300.com, KawBoy (He's a fart smeller! :))

Okay, here we go again.
As per the Service Manual
  

 

Resistance in a series circuit (which is the primary circuit in the ignition) is the addition of the resistances of the components in the circuit so in this case. if we add the resistance of the ballast resistor to the resistance of the primary winding of the ignition coil we get  1.5 to 1.9 ohms + 1.2  to 1.9 ohms we get a range of 2.7  to  3.8 ohms total primary circuit resistance permissible to be within Service Spec. 

Ohms Law states that Amperage = Voltage divided by Resistance so bearing in mind that the charging voltage of a running KZ1300 averages around 14.5 volts we can work out the amperage of the primary circuit. 
14.5 volts / 2.7ohms = 5.37 amps
14.5 volts / 3.8 ohms = 3.81 amps

The service limits as spec'd in the Service Manual basically states that we can run up to 5.37 amps in the primary circuit and this will not damage the control switches in the circuit which are the Darlington transistors in the igniter. 

So, as long as the  resistance in the  primary ignition circuit is maintained above 2.7 Ohms you should be fine. The only caution here from my point of view is that you would be running really tight to the maximum amperage that the Darlington's can handle and there would be no room for error.

I do remember that Trikbldr got in to this topic years ago and started explaining all the electronic theory regarding this primary circuit topic and he was adamant that "some additional resistor was required to dampen the (for the sake calling it something) reverberation of the voltage fluctuations in the primary circuit to protect the Darlington transistors. Trikebldr got really upset at members on this site referring to him as a blowhard and Trikebldr left us to our own demise and tootled off to his other favorite site American Voyagers Association since it was more in tune with his desires

"The CDI is expecting approximately 2.7 to 3.0 ohms so make sure it doesn't change."

• Presently, primary resistance is 4 ohms (1.7 ballast + 2.3 coil), excessive
• If all three ballast resistors are configured for parallel, resistance drops to 0.57 Ohms
• Overall resistance is then 2.3 (coil) + 0.57 (new ballast R) = 2.87 Ohms
• 2.87 Ohms is a smack-dab between 2.7 and 3.0 Ohms

Email to my buds...

Oh Lord it’s hard to be humble…

Found this really good post on KZ1300.com

From previous posts, folks have installed 3 discrete ballast resistors to replace OEM ballast. 
Any good reason for this? Why not just one? If 8 cylinder V8's use just one, seems like a 6 cylinder motoBike could use just one?

 

In my world, I'd like to use OEM ballast resistor as it's tucked away nicely.. and don't have to buy yet something else..
..wire it in parallel, get resistance down to .57 ohms for a total primary circuit resistance of 2.9 ohms.
 

 

Advisable or not? 

Thanks for the help guys, especially KB! 

2023-03-31 Spark Plug Caps - Ign Coil Rewire

Got to thinking about the Martek coils. They have 3 terminals. Two on one side, one on the otherside. Is it possible the second terminal is another tap of the winding?

When I installed these coils, ~1980, I remember not fully understanding the instructions.

Sure enough the second terminal, the with a '1' scratched by it, is has a resistance of 1 ohm. Perfect! The ballast resistor is 1.7 Ohms. Add 1 Ohm from the coil, 2.7 Ohms total.

Just wht the doctor ordered!

Total resistance, ballast resistor + coil. All 3 read the same value.

To think, a mistake I made 40+ years ago, never questioned, causing weak spark all that time.

I'm ashamed, but more happy than shameful, to have found this!

Things are looking up!

Checking high tension leads. First one pulled looks corroded. Not good.

Assuming a 5k Ohm cap resistor, a reading of 7.2 MegOhms is not good either.

The end caps are not the same length as 'inner' caps. End caps are shorter. This is an 'inner' cap. 
Pix for Mfr and part number.

End cap part number, e.g. cylinder 1 and 6.

Notes

1. Three of the 6 wires showed intial 'open' when measuring with DMM for Ohms. Corrosion where spring contacts wire connection.
2. The spring enters the cap first, followed by resistor, held in place with a 'nut' that has center hole which slides over spark plug end.
3. Caps for cylinders 1, 6 have built-in, non user removable 5k Ohm resistors. All other caps have removable spring, resistor, nut.
4. Re-gapped plugs to .035" from .030.

Happiness was short live however..

She won't start now. Cranks, but no fire. Checked for spark, yep, it's got spark. 

...and I've been having intermittent starter motor problems.. probably, hopefully the control switch? It hits, then, I'm therozing, opens, and the starter quits turning.

To be sure, changed the 2011 battery with a known good battery, same symptoms.

..and the one plug I pulled was bone-dry. Opened a float bowl drain, and fuel came out.

By then it's cold, dark, and I'm defeated.

She Runs Again!

Spark plug tester on Mowie-Mowie

2023-03-31 Broken Coil, Spark Plug Tester, Fix NO SPARK condition

The big idea to place primary resistance to desired 2.7 ohms failed miserably. Weak, almost non-existant spark.

Put coil primary wiring to 'As Found' condition, almost 4 ohms on primary, and spark returned. Glad I didn't damage the Darlington power transistors in the
IC Igniter

Position '3' is the 1 ohm winding. '1' is the higher resistance winding that works.

Starter motor relay re-work. Kinda loose wire in primary connector, cleaned all connectors, and leads going to starter motor/ground.
In the long run, didn't fix a thing. The starter kicks out after about 5 seconds. Releasing the starter button I can hear the relay kick out..

Split coil. I think it broke when the nut was tightened. Don't recall seeing the break earlier, and I was looking...

1. ACCEL-140403-Universal-Super-Coil
2. Yellow Square
3.  

'll take a picture, as mine were just recently separated and post it to help.

One picture shows the diagram for the coils. Notice the standoffs? Hexagon shaped pieces that space the coils from the plate in the headstock.

Thread rods extend through the plate (4) upwards and (2) downwards to mount the three coils with nuts.

The coil side of the stand-offs are mounted with Phillips (star) screws I believe.

Red circled holes are for the coils that hang upside down, yellow are for the one coil mounted on top.

 

Hope this helps

BP6ES iridum is BPR6EIX stock number 6637

edit

2023-11-19 Kz1300 New Coils Install

The temporary work gig at the nookie plant is over, about 1 week ago. Finding my civilian legs again, time to complete some projects.

How about we start with the bike already on the lift?

Pics of original install using Martek coils. I did this...1982 or so?

The Martek coil shape provided for easy install. Two on top, one on bottom.

I remember making these custom brackets in the Volumetrics machine shop, after hours.

The reason for replacement.

OEM ballast resistor. New coils don't require it.

New stuff! 7mm copper center wire from Ton's, coils by YellowSquare.

Ohms are 'in spec' to not overdrive Darlington transistors yet provide a hopefully HOT spark.

Won't be using these. Cheesy-Cheap.

Tucked in tight. 

Always good to label wiring.. especially on, uh, 'extended job durations'.

Off the bike now.

Can't believe these aluminum brackets lasted all those years.

.

Note to self. Coil and cylinders fired. Wasted spark syndrome!

Replacement coils slighty smaller. They did not come with nice hardware indicated by arrow... rather a cheesy screw/nut and tiny tiny standoff. Useless.

Did a fitment test with new Ton's 7mm wire. Fits into coil perfectly (screws in).

Yes. All metric fasteners. Don't believe in mix n' matching metric and SAE.

Looks ok. Almost good.

As caption says, not really bent. It's an illusion.

I need to bite the $$ bullet and buy a nice assortment of metric fasteners.

More room with new coils.

Mock up is good, so far.

Need to pick up more hardware.. One bolt too long, need more spacer sizes for optimal positioning.

... more later

2023-11-21 Final Pics of New Coil Installation

Almost done. Still have to connect primary windings to harnes...

All stainless hardware, metric.

Two under, one on top. Yes, they have to be removed to remove valve cover.

After all this hope they work better...

iPhone gives funny angles. The stand-off is actually straight.

Looking proper!

Eye candy!

Need some wire spacers still.

The End.

Now to wire the primaries.

Well, I didn't plan on the rad hose not fitting under the coil...

One should always think things through and not just 'know it'. Coil wiring for example. The three coils all had pink wires going to a ballast resistor on one end. The other end (yellow/red) tied back into the wiring harness. 

Out comes the ballast resistor. Now time to wire up the new coils. Should be simple, right? Connect the + side of coil to appropriate igniter wire. Take - side of coil to ground.

Then got to thinking about it... Better look at a schematic.

The question now is, how does this circuit really work?

1. Should coil negative be grounded and the ignitier (Darlington transistors) pulse coil primary to establish field that collaspes and makes secondary high voltage? Or,
2. Is 12vdc provided from Engine Stop Switch to the Pink wired side of the coils, and then the igniter is breaking current flow, thus inducing a field?

The diagram above shows the entire circuit.

Diagram above shows how I *think* the circuit works.. 

1. 12 volts is provided via a 10 amp fuse (#1) Brown wire.
2. Which then travels up to the Engine Stop Switch (#2, 3, 4)
3. Then through #5, 6, 7 to igniter / Darlingtons  (yellow red)
4. Refer to top diagram, the Igniter does it magic to open/make the circuit and induce volts into primary winding?

I think it's how it works..

Found more info...The diagram below shows the A1 ignition circuit. From FSM. Coil has been replaced, Resistor as well. So yes, coil + primary side needs to connect Yellow/Red from main harness (which goes to Igniter).

Final question is:

1. If coil is marked with a positive (+) terminal, should Yellow-Red be connected there? Or from one of the 3 colored wires from the Igniter?

Been doing a fan mod. Finally got water in the system meaning I could  spin the now-lubricated new mechanical water seal and check for spark.

Removed old plugs, brand new ones laid out across valve cover... 

and...

drum roll please,

Beautiful Spark. Strong and Blue, no wimpy yellow half witted sparklers anymore!

Clicky