SEM trigger coil information

Parsko · Jun 29, 2007

Does anyone know, or can anyone find out when the trigger coil has it's first rising edge w.r.t. the angular rotation of the stator?

A.k.a. the trigger coil going into the CDI unit will trigger at some point in the rotation of the Crankshaft. I'd love to know when this occurs with respect to TDC.

Have a look at:

Located at:
KTM LC4 SEM ignition

I kind of have this post pointed at Sparks, since he should have the gear available to test these numbers, or better yet, have them on-hand.

Sparks, can you get this info?

I'll have more questions to ask later, but I thought I'd get the conversation rolling...

Thanks,

-Parsko

sparks · Jun 30, 2007

Hi Parsco,

I can't imagin why you would want this infomation and what you would do with it once you've got it.
It sounds like you either want to higher your street cred or lower mine.

I've never really looked into it myself never really had the reason to. But basicaly once the pulse has been sent to the cdi then it is the circuitry that takes over regarding time lag or time lead irispective of the RPM. I have worked on this ignition before on a scope but I don't accatually own one myself.
At what RPM do you require the degrees at TDC?.

Can I ask exactly why you want to know this?.

Regards

Sparks.

Parsko · Jul 1, 2007

The short answers...

Why? I'm designing a fuel injection system for the older style motors, in my spare time as my hobby. I plan to replace the CDI with my own, and I want everything I design to be usable with existing systems, with no modifications other than add-ons.

I need to know because I need to run some calculations to tell me the lag between the Stator tigger coil and the CDI spark output. I know the CDI will fire around 32-36 BTDC, I'm curious when the Stator triggers the CDI (I already know it's the first rising edge of the graph above).

I went to the dealer and had him pull the flywheel (mine tools are in the US). I now know the state of this stator. The flywheel is a bit beat, and will need to be replace due to the magnets starting to pull loose, but I think I have time. My resistance checks are okay, but I will have you rewind my stator anyway.

Do you rewind both circuits, charging and ignition?
Do you do flywheels?

Re: flywheels, I looks like it would be pretty easy to re-pot these flywheels. Assuming the magnets are undamaged, I suppose they could be un-potted and re-potted with epoxy that is more water friendly.

Anyway, I have more questions still, but the F1 race is on in 40 minutes, and I have a few things to do before then....

-Parsko

sparks · Jul 1, 2007

Hi Parsko,

Ah now it makes sence, the fuel injection could be an interesting thing.
Regarding your magnets on the flywheel you can use an epoxy called Dephcon this will work well.
Also watching the F1 catch you a bit later on, from your last post sounds like you are not in the states.

Regards

Sparks.

Parsko · Jul 2, 2007

Hey Sparks,

Yes, I know about Devcon. I had a small amount of it a few years back that was given to me, but I never had a chance to use it. My concern is that it contains metal flakes, like some other epoxies. It probably does not though...

You never answered me before. When you rewind, are you only rewinding the ignition side of the Stator, or do you also do the power side of the stator?

Also, do you have, or could you draw, a wiring diagram showing all the bits inside the stator? I'd love to put it into my documentations. I know it probably doesn't matter, but I'd like know what is inside.

Also, I figured out that there are two (or 4) magnets on the ignition side. I'll try to grab a pick a bit later and post it. But, it explains the graph I posted above.

In my design, I'm thinking of not using the ignitions charging circuit (red/black) at all. I will run a system off of the 12V supply. Basically, like the Velleman ignitions circuit. I am thinking that I could use it to also charge the battery in addition to the power side of the stator. Not sure about that one yet, though.

More to come.

-Parsko

BTW - You mentioned New Haven in another post. I'm from Fairfield, about 30km away from there. How long were you there? Where are you in Spain again?

sparks · Jul 2, 2007

Parsko said:
Hey Sparks,

Yes, I know about Devcon. I had a small amount of it a few years back that was given to me, but I never had a chance to use it. My concern is that it contains metal flakes, like some other epoxies. It probably does not though...

You never answered me before. When you rewind, are you only rewinding the ignition side of the Stator, or do you also do the power side of the stator?

Also, do you have, or could you draw, a wiring diagram showing all the bits inside the stator? I'd love to put it into my documentations. I know it probably doesn't matter, but I'd like know what is inside.

Also, I figured out that there are two (or 4) magnets on the ignition side. I'll try to grab a pick a bit later and post it. But, it explains the graph I posted above.

In my design, I'm thinking of not using the ignitions charging circuit (red/black) at all. I will run a system off of the 12V supply. Basically, like the Velleman ignitions circuit. I am thinking that I could use it to also charge the battery in addition to the power side of the stator. Not sure about that one yet, though.

More to come.

-Parsko

BTW - You mentioned New Haven in another post. I'm from Fairfield, about 30km away from there. How long were you there? Where are you in Spain again?

Hi Parsko,

From what I remember no Devcon doesn't contain any metal fragments.
Yes I only rewind the ignition side the charging side doesn't suffer any problems.
Yes I will draw you an internal diagram of the coil layout and connections better still I will send you a photo.

I was in New Haven in the late eighties working for a company called Schulz Electric rewinding electric motors AC and Dc.I was there for about six months didn't get paid what they promised so returned back to the UK back to road race spannering. The town was called Hamden.

My location here in Spain is about 60 miles 100km North of Alicante (Javea) 1.5km from the Med.

Regards

Sparks.

Parsko · Jul 3, 2007

So, I managed to figure it out. Now, I understand better what is going on inside everything. Relevant information:

The Crank

- The keyway in the crank is aligned with the crank pin, and thusly "points towards TDC" when the piston is actually at TDC.

The Stator

- The stator, as it sits in the bike, "points towards TDC" also, with the flywheel alignment mark pointing 180deg opposite, or "towards BDC".
- The stator is mounted on slotted holes allowing a few degrees of adjustment in either direction, exaxtly how much is TBD

The block

- There is a mark on the block, near the upper left stator cover screw hole, that indicates when the spark fires, or about 32degBTDC

The Flywheel

- The flywheel, including trigger magnets, are aligned such that the trigger occurs at roughly TDC, or 0 degrees.
- The alignment hole in the flywheel, so one can align it to the stator, is offset from the 180 degree mark by 31 degrees.
- The timing mark on the OD of the flywheel - I don't know where that is located, I will check when I get home.

I assume the timing mark alignment hole in the flywheel being located at about 31deg from 0 is no coincidence. It would make sense, since the spark is supposed to fire around 32-36 deg BTDC on this bike. But, I can't get my tiny brain around whether there is a delay in the CDI unit, or if it fires as soon as the trigger is seen. From what I gather, it sees the trigger at 31degBTDC, waits about 300degrees, then fires the plug somewhere between 32-36BTDC. If you add up those numbers, they roughly equal 360 degrees. This is the exact question I am trying to confirm in this forum post!

I gotta think about this more...

-Parsko

Picture of degree wheel used with flywheel last night, looking from the block side, I'll post a pic of the setup later

CAVEAT: All values are +/-3 degrees, or-so. Exact values are To-Be-Confirmed.

DezDuster · Jul 4, 2007

4th

you've been working on that FI for a long time... hang in there.

MAW · Jul 14, 2007

EFI

Hello Parsko,

If you're interested in the destination rather than the journey you might consider just using the MicroSquirt controller. I built a couple of the full size MegaSquirt controllers for automotive projects and they worked great. The MicroSquirt (SMT construction) comes built, tested, and loaded with code for around $350, will control both fuel and spark, and is around the size of a pack of smokes.

http://www.microsquirt.info/

This is what I'm planning on using for my 550 when I get the time to do it.

Cheers, Mark

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