'82 450 Igniter - Repair, Replace, or Make?

[pete]

Thanks Pete, I will try and get it printed out and legible. I have an electrical engieneer at work who is going to look it over for me.
If he thinks its viable I will make one up and try it out. If it works I will let you know.

On another note Pete, I noticed the ignitor for the GS250 80/81 models is the same as the same year model GS550 which is a four cylinder. How is that possible does the coils on the 550 make it work or do two cylinders on the 550 fire symotaniously. (sorry for spelling)

Do you know of a aftermarket igniter which is available for the 550 which may work on our bikes?

Cool, that should be a great help! I also remembered that there's another schematic on here:

http://www.gs400.de/

This one is actually readable, except the site is in German. On the left, click "Technik", then click on "GS Zundmodul" and that's what I guess means ignition module in German or similar.

And yes, the four cylinder GS' only use two coils as two cylinders fire simultaneously, so some of the twin modules are the same as some of the fours.

The trick is the signal generator and governor on the end of the crankshaft, and sadly it seems the 400/450's are different to every other GS model which is really frustrating and means the ignitors aren't a direct swap.

Do a search for Spyug's work on his 550 ignitor stuff, as he was able to put I think a 750 ignitor in his 550 by getting the 750 signal generator mounted onto the 550, but it does require quite a bit of modification...

[pete]

look up "wasted spark"

Indeed Jeep! There is also wasted spark on our GS'

[pete]

And... expect testing to resume in the next couple of weeks!!!!

Got the GS back today...

[pete]

13th August is D-Day for the testing.

And on a side note, I discovered there's a Dynatek ignition setup to suit these twins apparently. The DS3-3C for $US309.99 is listed as "Dyna S Ignition System for Suzuki GS 400 Twin w/ Coils", so I expect it will be fine for the 450's as well.

If anyone following this was to go down this (expensive) path, then I would definitely be clarifying first. Interesting that it comes with the coils too, so no using the OEM ones.

Good to know there's a backup plan if I get too frustrated with the HEI setup too...

[Briars]

Pete, I had my electrical engineer buddy look over both schematics you sent me. The HEI one and Mr Matchless version of the stock unit.

He compared the two and decided the HEI version would work like the stock schematic. While it may be a bit bulkier it is the simplest way to achieve the desired result.

I will gather the components and give it a go in the next few weeks. I may need your help when it comes to wiring it up. I understand I will need two of the HEI units. (one for each coil) I will be following your progress as well especially if you get your test done before I do.

Thanks again and here is his version, which has one additional resistor just to the left of D1. I think he included it to protect the pickup coil from a power surge.

Edit (I also found this info on the BC547 or Q1) http://www.danielsoltis.com/notdatasheets/BC547.pdf

[pete]

Thanks Briars, that's awesome!

Interesting that the HEI one and the genuine are essentially the same result, but it does make some sense to me.

After everyone's input and looking at the schematics, it did seem to resemble it to my eye, but I was uncertain about that and am far too rusty in that area to be sure of anything at the moment.

It looks like he added D2 as well as R3, would be great if you could get him to clarify why for my benefit, but if you can't it's all good.

Thanks for letting me know any posting the schematic, I'm still on track to test next week too.

We did have plans today but my wife's ended up getting sick so even though I'm home I can't really kick it over, so next weekend it is.

[Briars]

Pete I had not noticed the D2. Thanks for pointing it out.

Below is a copy of my e-mail corespondence concerning the igniter.

The schematic the top post refers to is the modified one I posted below.

Maybe you can read thru the e-mails and make a bit of sense of it. Start at bottom and work your way up.

I will ask him monday if he can put it in laymans terms for me why he added the additional items.

From: Kevin
Sent: Tuesday, July 26, 2011 9:37 PM
To: Perry
Subject: RE: Igniter



Revised schematic attached …

From: Perry
Sent: Tuesday, July 26, 2011 12:57 PM
To: Kevin
Subject: RE: Igniter



Sweat, I guess I will owe you a Papa’s pizza and a pitcher or two on you next visit!

From: Kevin
Sent: Tuesday, July 26, 2011 8:54 AM
To: Perry
Subject: RE: Igniter



You will need the amplifier to use your pickup with the GM HEI module.

I will redraw the amplifier schematic and get you a revised parts list. You will need a transistor, some resistors, diodes and zener diodes, and a small project circuit board to tie it all together. May have to tweak resistor values to get it working right.

Regards … Kevin

From: Perry
Sent: Tuesday, July 26, 2011 8:32 AM
To: Kevin
Subject: RE: Igniter



Thanks for the footwork, I will gather the components and give it a shot

One question, in paragraph one you mention a amplifier, if I use the gm HEI will I need that?

Here is what I need to gather, correct if wrong.

1. 14 and 16 awg wire.
2. DR-100 quantity two one for each coil
3. Zener clamp quantity two one for each DR-100

From: Kevin
Sent: Monday, July 25, 2011 9:37 PM
To: Perry
Subject: RE: Igniter



Perry,

The HEI module is the way to go. I was able to find other websites that confirmed the wiring details to the module as shown in your attached schematic. The input stage is a simple amplifier to pickoff the signal from the pickup coil and would be easy to fabricate. It may have to be adjusted (tweaked) to match properties of you pickup coil. Push come shove … can implement a single chip amplifier using a component as seen in the attachment, and would then drive the HE module.

Heat sink real well. Use 14awg on power lines (to coil, and to wires attached to terminal B and C). Use 16awg elsewhere (but 18awg would work in a pinch). May have to swap polarity of pickup coil to get it right. I would add a zener clamp to the input to provide over-voltage protection to the circuit. Easy fix. Otherwise it could work as you have it drawn in the GM HEI schematic.

Autozone carries a module as part number DR-100 for about $20. Advance Autoparts carries a GP Sorenson part EL-102 that should also work. Hell … you should be able to go to any junk yard and find a late model GM and strip the part for next to nothing, and have a better part than you could buy aftermarket.

Hope this helps. Have fun with it.

Regards … KEvin

[pete]

Thanks again Briars (can I call you Perry now? ).

The only thing in the email I see there is he mentions a zener diode, but he hasn't put any in the diagram.

If he put a zener anywhere, it would make sense to me to put it as D2 which would protect the circuit from spikes generated by the coil.

I think he may have said D2 is a 1N4004 when it should in fact be a zener diode, but I may be wrong and he may think it should go somewhere else. As I said, I'm far too rusty with this stuff to be sure.

I would definitely ask that question to clarify though to be sure.

In the meantime, I'll stick it into LT Spice here and see what that shows me as the output.

[pete]

I just put the updated schematic into LT Spice but because I don't know how to put a coil in like the pickup coil works, I'm not getting it to work properly at all, so probably best to check with your mate to clarify that one.

[pete]

Well, I got time today to give it a kick, but didn't get the results I was hoping for I'm afraid.

Fortunately, John (john82q) was able to come around and I'm really glad he did otherwise I'd have had no clue at all as to what was going on.

As it turns out, it looks like my richness issue during the first start was only one of two problems, but I couldn't see the second problem because I couldn't get the timing light on it enough to see what was happening. I still would've been lost if I could get the timing light to work, but I would've at least known something wasn't right with the timing.

Anyway, we were able to get it idling somewhat today but it was backfiring continually and any throttle would make it worse.

We were trying to see if the timing was right by making sure the F mark was lining up with the timing mark as it should, but instead it was way off near the T mark which is just plain wrong.

So, we enlarged the slots a bit for the mounting screws to let us advance the ignition some more, which made it marginally better, but also at this point John realised that the T mark we were seeing was 180 degrees out!

So, with the screws out completely, John was keen enough to hold the signal generator plate in place and rotate it and it definitely got better and better, but of course we had no ability to get the timing light in there as the cut out for the timing marks was now rotated away from being useful (if that makes sense).

End result is we have two alternatives; one to lengthen the cut outs for the screws and timing marks, the second to revisit the circuit and work out why it's firing 180 degrees out.

First thing was I tried swapping the G and W connectors on the HEI modules, but that resulted in no spark at all.

So I disconnected W and left G on, and that ended up exactly the same with 180 degrees out of whack.

So, at this point John volunteered to extend the holes in the signal generator plate and to mark a new F mark 180 degrees out on the advance plate.

He dropped them back this avo but unfortunately I wasn't able to get in and give it another go today. I may or may not get time tomorrow, but I'd say at this stage it's unlikely I'll get the chance.

First pic shows the extended cutouts, second pic shows the new F mark up the top, 180 degrees out from the correct F mark:



I'll do some more reading up on the HEI modules again as my memory's getting a bit hazy with them now and see if I can't work out why it's so far out. It could simply be a matter of the transistors are causing too much delay in triggering the spark, but I'll see what Lou has to say as well.

Unfortunately the dwell meter function on the new auto multi meter didn't seem to do much today. Not sure if that's because it can't cope with the wasted spark or if the dwell angle really was 180 degrees (max it can display).

Anyway, bit of a disappointing day, but there is definitely still hope, and hopefully the modified plate allows it to fire as it should or, alternatively, I can work out why the ignition setup is firing so far out.

John, thanks heaps once again for your help today, I really appreciate it. I would've been completely lost!

[pete]

So I was typing up a quick email to Lou this morning to update him on the not so successful second start, and then it dawned on me that early on in our email trail he mentioned something about the resistor values I was using and that they could potentially cause the transistor to turn on too slow.

Here's the quote from the email:

I see one issue with your circuit regarding timing. The input impedance of the amplifier you created is only about 4.7k ohms. Normally you would want to be in the 100k to 1 meg range (ideally infinite). This will allow some current to flow in the pickup. As the RPMs go up, this will retard the spark more and more since current lags voltage on the inductor, and the transistor is a current-driven device. It may be fine at idle, but will run worse and worse as the RPMs increase. This effectively work as an RPM limiter (that's how some racing limiters actually function). However, since the resistance of the pickups, in your case, are so low (strangely low, in fact) there is a chance that your pickups would be more tolerant of low-impedance-input circuits. The test would be to view the pickup/rotor with a timing light and see how far the rotor moves past the pickups at the flash, as the RPMs go up.

I have no idea why I never took heed from that advice and left it how I had it, so I decided this morning that I should up the 4K7 to 1M and the 47K to 10M to see if that solves the fact that it's so far out.

So I got to do that tonight:



And it's all set to go again:



I'm struggling to find a way to get time to start it again before the next available Saturday in 3 weeks, and I may be able to get this Friday off to try again.

John, I know you'd probably like to see how it goes in person again, but if I don't do it on a day off from work, I'll be waiting 3 weeks for a Saturday and I really can't wait that long...

[bakalorz]

I just put the updated schematic into LT Spice but because I don't know how to put a coil in like the pickup coil works, I'm not getting it to work properly at all, so probably best to check with your mate to clarify that one.

If the pickups output is a sine, you would use a sinusoidal voltage source in series with a resistance equal to the pickup coil resistance. If the pickups output is more complicated than that there are various approaches ...

since the pickups output would probably change amplitude with RPM you would probably want to do multiple runs with different output voltages...

But in the end, your sim is only as accurate as your pickup modeling, so you would have to look at the pickup with a scope on a running engine to get a decent pickup model, after that you could play with various amplifier input schemes to see how they stack up in the sim ... but I suspect its likely that it would be just as easy to try different inputs in real life till you get one that works.

[pete]

Thanks Martin, that all makes sense, and it's a little frustrating I was never able to get a good and accurate idea of what the pickup coils are generating signal wise. I suspect my inability to operate John's scope adequately was the cause of that...

If I get some time this week I might have a further play with LT Spice and see if I can't confuse myself even more.

Also, I've scored Friday off work this week, so I'll have time to test the modified circuit out and the modified signal plate. Bring it on!

[bakalorz]

Thanks Martin, that all makes sense, and it's a little frustrating I was never able to get a good and accurate idea of what the pickup coils are generating signal wise. I suspect my inability to operate John's scope adequately was the cause of that...

If I get some time this week I might have a further play with LT Spice and see if I can't confuse myself even more.

Also, I've scored Friday off work this week, so I'll have time to test the modified circuit out and the modified signal plate. Bring it on!

Re: the modified signal plate ...

If I recall correctly you were 180 out of phase ?

To me that suggests that rather than changing the signal plate that you might want to add another stage to the amplifier and invert the signal ...

Its probably easier to do too ...

[pete]

Yeah we talked about that on the day and I attempted swapping the HEI module inputs around to achieve just that, but apparently it's not that simple.

My thought at the time was to swap the BC547 setup for a non-inverting setup but the quickest answer right then and there was to extend the holes to see if it really was 180 out. John has the gear and is willing to use it

Anyway, I'll see how it goes on Friday with the higher value resistors, might be enough to bring it back to where it should be.