Coil circuit confusion

[katanarider]

Hey guys,
As some of you may know I've been having trouble getting my Kat 1100 to start. I've previously posted a few questions which lead me to believe my Ignitor box was faulty. I understand that I'm supposed to have 12v on both coil wires or all 4 wires when referring to both coils. However, it was my understanding that both sides of the coil were supplied with 12v from 2 separate sources. After buying 4 Ignitor boxes I've not had a single box pump out 12v to the other side of the coil. This made me dig deeper and test the coils off the bike. As it turns out both sides of the coil do in fact have 12v , but only the main power source supplies it all. In other words, if you remove one wire from the coil (the one that returns to the Ignitor) the naked terminal will show 12v supplied by the main. I've also noticed the schematic in the repair manual that seems to show the same thing (I've attached the picture). So with all of that said, I'm confused. I'm not sure if I have faulty coils (both test the same) or how the coil is supposed to charge. I'm trying to create spark on my bench table, but if I touch one side of the coil to the negative it creates a short circuit, it just sparks at the battery terminal.

[katanarider]

Oh yeah, I tested the resistance on both primary and secondary. It all checks GOOD according to the repair manual.

[Kreylyn]

The coils don't "charge" per say. It's not a build up of energy that is then released like say with a capacitor.


Each terminal is it's own separate circuit. Both ground out to the frame.


The coils works by both circuits creating a magnetic field when energy is applied This is just like an electronic magnet. It's immediate and not something that needs to "charge up" or "build up".


When 2 separate magnetic fields interact such as the case would be here, and then you have one of them suddenly go away, it will cause the other field to "collapse" sending a surge of energy.


That's what generates the spark. The stronger the fields, the more energy that will be created and the hotter spark you will get.


So... your cdi should be sending 12v to both input on the coil. The CDI will then cut power to the signal wire for a millisecond, causing the other field to collapse and generate the spark. Power is restored to both immediately for the next time the signal wire needs to generate that spark again.


Grounding out the signal wires is how the kill switch works to kill the engine. The coils stop firing because they are no longer receiving the 12v on both wires.


Perhaps you should check your kill switch and other safety switches that kill the engine as they may be possibly faulty, and is why your not getting 12v on both wires at the coils.


Krey

[katanarider]

So... your cdi should be sending 12v to both input on the coil. The CDI will then cut power to the signal wire for a millisecond, causing the other field to collapse and generate the spark. Power is restored to both immediately for the next time the signal wire needs to generate that spark again.
Krey

12v is constant on both coil terminals (referring to single coil) which is supplied my the main power source. That electricity does not break unless the power switch on the handle bar is turned off. Thats what I was saying in the original post. The Ignitor box/CDI does not supply any power to the coils at all. I've taken the time to paint it for you.
Coil #1
Terminal 1= 12v In from handle bar switch
Terminal 2= 12v Out to Ignitor


Coil # 2
Terminal 1= 12v In from handle bar switch
Terminal 2= 12v Out to Ignitor


Ignitor= Three 12v power In/ 1 source from handle bar switch and 2 from the coils/One each.

[Kreylyn]

12v is constant on both coil terminals (referring to single coil) which is supplied my the main power source. That electricity does not break unless the power switch on the handle bar is turned off. Thats what I was saying in the original post. The Ignitor box/CDI does not supply any power to the coils at all. I've taken the time to paint it for you.
Coil #1
Terminal 1= 12v In from handle bar switch
Terminal 2= 12v Out to Ignitor


Coil # 2
Terminal 1= 12v In from handle bar switch
Terminal 2= 12v Out to Ignitor


Ignitor= Three 12v power In/ 1 source from handle bar switch and 2 from the coils/One each.

Okay, I misread and thought you were having a loss of power issue.


So... what is the problem when you try to start the bike with everything set up on the bike correctly?


Krey

[katanarider]

Its turning over but no start. I just installed the Relay Mod about 1 hr ago. The battery is charging currently and its freezing cold out. I'll report back with results later.
Since I've bought the bike its not ran at all. I got it home fixed a few things then tried to start it. I knew it wasn't getting fire to the plugs because I pulled the air filter and sprayed starting fluid in the carbs, and nothing. After posting my old thread you had me thinking I was supposed to have 12v coming out of the Ignitor to the coils (I forgive you ). Anyway, since then I've been hunting cheap Ignitors and testing them off the bike for voltage coming out to the coils. Who knows, the others may work. So, after $65 of Ignitors (Yeah, I'm a smart shopper, some times ) and a massive amount of Youtube videos I decided to defy your advice While this current Ignitor was in the mail I seen a video that showed the plug boot resistors that explained frying a coil can blow a Ignitor. Off came the coils for a check up, all good. Next video showed how to bench test coils. This was the closest I found to the dual fire coil but its not working for the Kat.

https://www.youtube.com/watch?v=u0WdphKGm7Q

The only guess I have about that is the ground on the Kat is the mounting tabs on the coils. They are metal ! I'm guessing at some point they ground to the frame when the signal generator does its thing. This is all a guess, I should have tested that before re-installing them.

Thanks for your time Krey !

[RobertTravis]

In situations like this, I check for spark first, then fuel. You can check for spark in seconds by pulling off a boot and spark plug and lay it somewhere in your line of sight...like on the valve cover. Then crank it. Do you see spark? If yes, then you got spark. If no, then pull another one, from a different coil, and repeat. If still nothing, then back track it and find where the magic smoke leaked out. If yes, then the first coil is toast.

[Kreylyn]

I don't remember ever talking about the ignitors... those like almost never go bad. GSXFJim's bike is the only one I've heard that was an actual problem, because of a different electrical issue having fried stuff.


Anyways, I agree, lets go back to basics and verify the bike is really not getting spark.


Krey

[katanarider]

BOOM !
4 trys= 3 times running the battery dead, 4th time used the Kat 600 to help jump start with my neighbor holding the throttle wide open as I spray starting fluid and ...
GROWL ! It ran so smooth for 3-4 seconds. 2nd start revved like the carbs were freshly rebuilt.
Good God Almighty ! I'd just like to thank God, Craigslist, Katriders.com, Youtube and Ebay.
The beast is back !
Ok, got to tie up some loose ends and get some good gas.

[92xjunker]

I for got about the initial starting fluid start up thing, used that twice. Then I started buying carbs from Arsenic, no more staring fluid...

[katanarider]

I for got about the initial starting fluid start up thing, used that twice. Then I started buying carbs from Arsenic, no more staring fluid...

I've accumulated several cans of starting fluid over the years from convenience stores, grocery stores etc... due to brake downs/no starts/being stranded I guess that tells you what class of vehicles I drive Anyway, those cans have got to get used at some point. It never ceases to amaze me how you can buy starting fluid from all these places but none of them sell "Carb Cleaner" which essentially also doubles as starting fluid as well. Who knows
When Arsenic puts together a step by step how to on how to convert the Kat-11 from 34mm to 36mm carbs then actually starts building them for that purpose, I may give him a shout.

[4wred]

I've considered putting fuel injection on mine at times,i'm sick of playing with these carbs all the time!!

[katanarider]

Go for it. Be sure to do a write up.
Theres atleast one thread here on how to convert the little Kat because I've seen it.

As far as this thread topic is concerned, I've become more educated on how the Inductive Ignition Coils work. I can't really explain it completely but Fardays Law helped me to understand. So yeah, they stay charged all the time by the battery. Then the battery charge circuit is broken which causes the built up voltage in the coil to re-route and discharge through the spark plug because its the path of least resistance/ground=spark.