Question about ignition coil

dsducati said:

Thanks from me as well for the great explanation Dale. I thought my 96 coil looked too small too contain anything other than the coil. Didn't the old Motoplat operate on a principle same as 96 SEM?
dan

Click to expand...

Gentlemen,
Thank you for the kind words, you are indeed welcome.

Dan,
The early SEM Husaberg Ignition system is very much akin to that of the Motoplat.

Indeed that tiny little coil also housed the capacitor and circuitry necessary to control it.

Best Regards,
Dale

To whom it may concern,

As I said in my earlier post i have been trying to put together a document over the last two months that will better explain and in many instances give more details of each part of the ignition system and the functions of each component. This has been an overwhelming task for me because I am starting with no background on this subject and trying to learn everything for myself using other people, the internet, and books as my educational material. There is very little info on SEM ignitions which are different from most, but I am piecing things together little by little and hope to be able to role out something for others to view in the upcoming months. My biggest obstacle right now is gaining a better understanding of what is inside the CDI coil box? I do know that there is a microprocessor which appears to be built on RISC (Reduced Instruction Set Computer)arcitecture and this is where the timing and spark trigger is computed.

Dale, In my investigation I have read about the thyristor you spoke of. Also in my study of this subject I have come across a device called an IGBT (Insulated Gate Bipolar Transistor) switch which I am thinking are one in the same. As of right now I believe that there are four main components inside the CDI/coil housing and they are the following: The microprocessor built on RISC technology which is the programed brains of the ignition and holds the pre-programed ignition curves, it works on one clock cycle (More will be discussed on this later). The IGBT which is the high voltage switching device needed between the capacitor and the "step-up" Ignition coil to initiate the spark. The IGBT is opened and closed by the microprocessor which is being feed readings by the Trigger coil of the stator. The capacitor which holds the charge from the secondary windings of the stator (@ 250V) and is waiting to be dumped into the Ingnition coil. The Ignition coil which steps up the voltage from the stator coils at a ratio of about 100:1(30K-35KV).

If anyone has a used coil that serves them no function I would love it if you were willing and able to send it to me for reverse engineering. I am wanting to try to dismantle it so that I can take pics and see exactly what is inside this "mysterious black box". I would of course pay any shipping expenses that would be required.

Any further discussion would be welcome and greatly appreciated.

Regards,

Hi Keith,


Generic CDI Controller.

Ignition 101:
http://www.jetav8r.com/Vision/Ignition/CDI.html

A good resource:
http://www.msefi.com/index.php?sid=51ae ... bbb4263b02

Keep up the great research!

Sincerely,
Dale

Excellent for the ignorant (myself): http://en.wikipedia.org/wiki/Ignition_system

Dale,

Thanks for the link resources you supplied in your previous post. I have been to the first link (JetAv8r) for allot of my information already and it has given me a good foundation for the principles of these ignition systems.
The second link (msefi) I have not checked out before. I took a quick glance at it and my brain started to hurt :scratch: , a bit more information than I know what to do with. I will have to read some more to see what I can make of it.
Thanks for comments and also the links as they will provide useful in this topic im sure.

Regards,

I just threw this together real quick but should give an idea of how the ignition coil & CDI box works. I believe this to be correct to the best of my knowledge.

Kind regards,

sandskipper said:

I just threw this together real quick but should give an idea of how the ignition coil & CDI box works. I believe this to be correct to the best of my knowledge.

Kind regards,

Click to expand...

Excellent Job!

The capacitor charge coil provides a wide range of voltage levels (rpm dependant). During cranking said voltage is well below 100. However, enough to boost the ignition jumping a 1.5 mm plug gap in open atmosphere.

Trigger voltage levels also vary considerably with rpm.

Most often the minimum trigger threshold has proven to be in the neighborhood of 3.5 volts.

Unfortunately, many "New" SEM stator units will not provide said minimum trigger voltage during electric start as rpm is too low. Hence the SEM equipped Husabereg which will boot start yet fails the "E" start test.

I once used a stun gun generator to pre charge the capacitor as I was first under the impression ignition output during cranking was insufficient.

What I learned was trigger threshold output was the culprit, not lack of secondary voltage.

Enter Kokusan.

Hope this helps.

Great stuff!
Please continue.

Sincerely,
Dale

Dale,
There is a discussion on another post about an SEM being weak or not. At minimal cranking speeds (just higher than minimum required for the pulser to fire) how many KV can be expected at the spark plug when all is well? Thanks in advance.
dan

dsducati said:

Dale,
There is a discussion on another post about an SEM being weak or not. At minimal cranking speeds (just higher than minimum required for the pulser to fire) how many KV can be expected at the spark plug when all is well? Thanks in advance.
dan

Click to expand...

Hi Dan,
Assuming a maximum gap (infinite even) 25K - 30K volts.

Unfortunately, the infinite gap test usually proves fatal to the coil as it shorts through to the primary windings.

As per Motoplat:
Never kick your engine over without the secondary lead being grounded.

Best Regards,
Dale

LINEAWEAVER said:

As per Motoplat:
Never kick your engine over without the secondary lead being grounded.

Click to expand...

I remember seeing that same information warning label affixed to a brand new 1972 Puch 125MX

When I was stupid enough to race jet skis, I remember my ski having little metal tabs to ground the plug ends to the block if (actually when) you drowned it out and wished to pump out the offending lake water. Also remember a lot of conversations with Harry Klemm. Have a funny feeling, Dale, that considering Harry's line of work that you personally know him. Was a warning that the ignition could be fried if advice was not followed. On the contrary, have seen the spark plug wire come off of many Japanese MX bikes with no resultant problems even though was told by Honda people that damage could result? Some guys are just lucky I guess.
dan

The capacitor charge coil provides a wide range of voltage levels (rpm dependant). During cranking said voltage is well below 100. However, enough to boost the ignition jumping a 1.5 mm plug gap in open atmosphere.

Trigger voltage levels also vary considerably with rpm.

Most often the minimum trigger threshold has proven to be in the neighborhood of 3.5 volts.

Unfortunately, many "New" SEM stator units will not provide said minimum trigger voltage during electric start as rpm is too low. Hence the SEM equipped Husabereg which will boot start yet fails the "E" start test.

I once used a stun gun generator to pre charge the capacitor as I was first under the impression ignition output during cranking was insufficient.

What I learned was trigger threshold output was the culprit, not lack of secondary voltage.

Enter Kokusan.

Hope this helps.

Great stuff!
Please continue.

Sincerely,
Dale

Click to expand...

Dale,

In reference to your comment about minimum trigger voltage being 3.5 volts.... Can you tell me @ what RPM this is usually achieved granted we are working with a "sound" stator? I think I remember reading a post by you before that this occurs @ ~750rpm, can you confirm this?

Also, do you mind if I use the information we discuss in this thread, and possibly others with this topic, for figures and such in the document that I am putting together? I will of course give credit to my sources of information.

Thank you much. This discussion has proved to be an opportunity for me to obtain valuable feedback and information as well as test my theorys. I really do appreciate the feedback and information and hope that anyone who has specific knowledge on this subject or the workings of the electrical system will weigh in on this topic. This information is intended to benefit all Husaberg enthusiasts now and in the future.

Thank you all for your help.

Regards,

Hi keith,

The unfortunate truth is trigger voltage output varies stator to stator even as new. Hence some Bergs which start better than others. Such being said and as a general rule 400 to 600 rpm.

You are welcome to use anything. I am indeed flattered.

Sincerely,
Dale

this is great info...

Thanks everyone, very helpful post.


Anyway, I've just come to realize that my coil is fried.(99 FE400, no e-start) It is sparking erratically, and I've replaces the SEM stator with the equivalent KTM unit. (interestingly, the SEM is identical, but the alignment mark is different, I guess the window whole location on the KTM is different).

Anyway, I'm assuming that I can't use a KTM coil because of the resident electronics to control the spark timing/advance.

Where the hell do I get a new coil that works? I think 99 was the first year for the DFC stuff, so I'm guessing it's not controlled via analog.....

Thanks for your help.

Nick

PS. I know I should have test the stator first, but it was rusted on the contacts and showing cracks in the epoxy...so I figured it was the problem(would have been anyway eventually)....I realized it wasn't the issue with my sputtering and finally inability to start the bike after I installed the new ignition and still got inconsistant spark....so officially I'm an *****.

RE: this is great info...

I've discovered a new coil for my bike is over $400, but they are much less for '98 and older models, and even less again for KTM versions....

Does anyone know for sure if the SEM ignition coil for earlier models would work? Based on what I'm reading above the difference is strictly analog/digital if you don't care about a high/low switch.....but then again maybe I'm reading wrong...

Thanks for any help anyone can offer....

Re: this is great info...

Nickelodeon said:

Thanks everyone, very helpful post.


Anyway, I've just come to realize that my coil is fried.(99 FE400, no e-start) It is sparking erratically, and I've replaces the SEM stator with the equivalent KTM unit. (interestingly, the SEM is identical, but the alignment mark is different, I guess the window whole location on the KTM is different).

Anyway, I'm assuming that I can't use a KTM coil because of the resident electronics to control the spark timing/advance.

Where the hell do I get a new coil that works? I think 99 was the first year for the DFC stuff, so I'm guessing it's not controlled via analog.....

Thanks for your help.

Nick

PS. I know I should have test the stator first, but it was rusted on the contacts and showing cracks in the epoxy...so I figured it was the problem(would have been anyway eventually)....I realized it wasn't the issue with my sputtering and finally inability to start the bike after I installed the new ignition and still got inconsistant spark....so officially I'm an *****.

Click to expand...

Hello Nick,

I don't think there is a direct KTM replacement (from a functional compatibility standpoint) for the 99-03 Husaberg SEM stator.

If you would be good enough to measure the DC resistance between the stator Red-Black leads and the Green-Black leads and tell us what you read I can tell you if the KTM stator you bought is suitable for your 99 Rotor (flywheel).

If the red-Black is 3000 + - 300 ohms and the Green-Black is 168 + - 17 ohms then they should be compatible.

While you are at it, make the same measurements on your old stator.

I use 2 straightened paper clips in the stator pigtail sockets to make good contact for the ohm meter leads.

Let us know what the measurements are on both stators please.

As to the coil, you best bet is to get one off of ebay if you really need one, thats where I got one for a bench test set.

You might also check the DC resistance of the spark plug cap. Just unscrew it from the coil high tension lead. The value is stamped on the cap, I think it is 7500 ohms. If the cap circuit is open, then that could be your problem if everything else is good.

Let us know what you find and we can discuss solutions for you.

Regards,

Joe

Re: this is great info...

***deleted***

RE: Re: this is great info...

Thanks, you did an awesome job.

Hello Nick,

Thanks for the data.

I question some of your data though. Are you using an analog or a digital meter? It sounds like you are using an analog meter. If you are, then make sure you have zeroed the readout needle with a screw driver before hooking the leads up to the meter. Have the meter sitting flat on a table while doing this. Then connect the leads to the meter, select the ohms scale you wnat, hold the lead tips together and adust the "ohms adjust" thumb wheel to rezero the meter to zero. Then you are ready to make the measurement for that scale. You have to rezero with the thumb whee lfor each scale change whem measuring resistance.

Its better to use a digital meter for these measurements though.

I lied, the spark plug cap on my 00 501is 5000 ohms, I just looked at it with a strong flashlight. To measure your you have to unscrew the cap from the coil high tension lead.

What value is scribed on yours? Please measure it again. I don't know whatresistance the 89-99 caps were.

If yours is bad that may be the real reason the bike will not start.

So please check it again!

Your reading of "aorund 350 ohms" for the Husaberg Stator Green-Black leads is also WAY off, it should be 168 ohms +-17 ohms, so please measure it again, and tell us exactly what it is. The reading you made for the Red-Black is good so you need to remeasure the Green-Black again, your Husaberg stator may be O.K. If the Green-Black measures to spec, then reinstall the Husaberg stator to the bike, leaving the pigtail connector unconnected from the bike wiring harness and run the following test.

Connect a good digital multimeter to the Red-Black leads on the stator.

Set the meter to VAC to some scale above 35 VAC press down the Max hold once and kick the bike about 3 times as if you are trying to start it. The reading should be ~ 30.0 VAC.Write down the data and clear the data from the meter. Repeat this procedure this several times recording the actual values for us.

Then repeat the above procedure while connected to the Green-Black leads but with the VAC scale set to the lowest scale over 3 VAC. The reading should be ~3.0 VAC.

IF the VAC readings are good and the spark plug cap is good the bike should make a spark. Remove the spark plug and connect it to the coil lead. Ground the plug threads on the engine and look for a spark as some on kicks it for you. Do this in the shade, bright sun light will keep you from seeing the spark.

If you get sparks then the bike should run if the carb, fuel, valves, etc are all O.K.

The KTM stator readings don't look correct either, so maybe you could measure them again.

As to the coil measurements, the only ways I know of to verify a coil is to try in on a bike or to test it with a dedicated Sems CDI Bench Tester.

I would buy a new SEM Spark Plug Cap if the resistance is more than 10% higher than the value scribed on the cap.


Well thats enough for now, let us know!

Regards,

Joe

***deleted***