A new found Electronic ignition system!

[Blurredman]

Got a picture/link, Arny?


This Muller one, as mentioned has the benefit of not needing the seperate box, and supporting 6/12v out of the box.




Guesi's ignition is a hundred euros..

https://www.guesi-motorradteile.de/inde ... ng=contact

[arny]

There are some fine ignition systems out there, but they are quite expensive indeed. Not that it's bad in itself, but when you consider the price of the bikes themselves... well, I've bought my entire ETZ250 for the price of a Powerdynamo system for it... So I must say I quite appreciate a cheap electronic ignition solution.

I'm not sure if it's ok to post links to products here, but here it is, Blurredman: http://www.gotronic.ro/new/index.php?op ... 59&lang=en

Their site is partially translated to English, but some parts are in Romanian which makes it a bit hard to navigate there. The linked model fits MZ bikes, and it works with the factory cam, which makes it even cheaper than it is for other bikes unlike Jawas for example, which need additional parts. Unfortunately the ignition from the above link also doesn't have English documentation but only in Romanian, but there is this, for a slightly different model but it seems there are no substantial differences for the end user: http://www.gotronic.ro/new/images/stori ... nglish.pdf

If it's not ok to link this, mods please delete; not that they pay me or anything

[Puffs]

Thanks for sharing that Arny!

Keeping the original cam indeed makes things even easier. Set at 0.5 - 0.7mm from the crest of the cam.

I can see why they require an alternative cam for the Jawa, their lift profile is odd (it has the highest point just before the points close, so that they close with a bang). I suspect their sensor has an internal magnet, the field of which is modified by the proximity of the steel cam when that rotates (in any direction). The field modification is then sensed by an Hall effect.

System for 12V only, and their range of 8 - 18V should be fine.

But of course points normally work fine too on an ETZ, and adjusting them is easy & you have to take the cover off to lube the chain anyway.

[Blurredman]

I'm tempted to create a thread sticky that lists all electronic ignitions and invite others to post on it to be added. Prices, disadvantages or positives of certain systems, etc

[Puffs]

That sounds ambitious. For that to be useful, it has to be complete, reliable & it needs to be kept up-to-date.

Anyway, this/your thread is a starter, and anybody can add.

[DAVID THOMPSON]

a system for the new 4 cycle 125 bikes would be nice

but have had very few comment on people needing a replacement
Dave

[arny]

When discussing electronic ignitions I guess it would also be interesting to mention which ones do control igniton advance...

So far the only one I am aware of that does automatic advance is Powerdynamo/VAPE ignition. Most other aftermarket ones including Gotronic I mentioned, don't vary ignition advance but are simple "transistorised ignitions" i.e. serve only as maintenance free points replacement.

Are there other aftermarket ignitions that vary advance timing automatically?

Does any of the stock MZ electronic ignitions vary advance timing automatically?

[DAVID THOMPSON]

Does any of the stock MZ electronic ignitions vary advance timing automatically?

500 rotax and the 125cc new 4 stroke bikes and the 660 motors

[Puffs]

Arny, I don't know the answer to your question insofar as pertaining to electronic ignitions for the older 2T MZ engines.

A question I have is: are you sure that Powerdynamo/Vape advance the ignition timing? Would you have an advance curve?

[Guesi]

When discussing electronic ignitions I guess it would also be interesting to mention which ones do control igniton advance...

So far the only one I am aware of that does automatic advance is Powerdynamo/VAPE ignition. Most other aftermarket ones including Gotronic I mentioned, don't vary ignition advance but are simple "transistorised ignitions" i.e. serve only as maintenance free points replacement.

Are there other aftermarket ignitions that vary advance timing automatically?

Does any of the stock MZ electronic ignitions vary advance timing automatically?

Our ignition changes ignition from 15 degrees to 23 degrees, depending on the revs.

[Puffs]

OK Guesi, so you set yours statically at 1.4mm bTDC rather than 2.7-3.0 mm bTDC?

Can you share an advance curve?

[Guesi]

Yellow :Stic ignition timing 23 degrees
grey: Static ingition timing 15 degrees
green: our programed ignition timing

Our ignition tries to keep the time before ignition at 1,3 ms over all the rev areas.

[arny]

Then I'd say ignition from Guesi is really worth trying, for other ones in that price range don't have automatic advance!

Arny, I don't know the answer to your question insofar as pertaining to electronic ignitions for the older 2T MZ engines.

A question I have is: are you sure that Powerdynamo/Vape advance the ignition timing? Would you have an advance curve?

Yes, I've seen their specs, but unfortunately I don't have any links at hand. They're too expensive for me, so I haven't really kept much info on them. I guess it could be googled easily...

[Puffs]

Arny, no, I'm not so certain I can find any advance curve that is indisputably linked with Vape or Powerdynamo ignitions for these 2T engines. True, there are some curves on the internet, but I'm not sure what those are for. Particularly Powerdynamo has shown some curves, but those are for 4T engines. For 2T engines, have a look here: http://www.powerdynamo.biz/eng/kb/2strokeadvance.htm. See that there is up to 10° retarding (not advancement) at very low RPM; that is due to the nature of the electronic parts used. But that low RPM retardation helps starting, in that it reduces kickback. However, normally no high RPM advancement on 2T ignitions.

Guesi, thank you for that graph. It is not an advance curve, instead it shows the ignition timing, in ms bTDC, as a function of the engine RPM. An important part of that graph are 2 curves displaying that ignition timing for 2 fixed settings of 15° & 23°bTDC. Those curves are easily calculated, for instance the one below is for 21.5°bTDC, the data of which I published earlier on this forum.

Ignition timing [ms] for a fixed 21.5°bTDC setting.jpg (9.69 KiB) Viewed 39 times

It's just calculated, a mathematical truth, not an ignition advance curve.

Yet obviously, with your green curve you are showing a clear departure from the grey (15° = 1.4mm fixed) curve, showing (for instance) 0.8ms advance at 5000RPM. That green curve depicts an ignition timing that is clearly advanced wrt the 1.4mm fixed curve, as from ~1700RPM onwards. I would estimate your green curve constitutes some 32° (sic!) advancement around 7000RPM, so equivalent to an ignition timing of around 47°bTDC. I see the curve, but are you sure that is what your system does? Are you willing to share empirical data to support your claimed green curve?

At any rate, with your graph you are addressing something highly desirable, at least in principle. You don't want the ignition to happen at some angle °, or mm before TDC, you want it to happen at some time, so ms, before TDC: you want the flame front to advance a significant part into the combustion chamber, so as to optimise the build-up of pressure, to generate the work when the piston will start to move downwards. So that is linked to the speed of the flame front, and the size of the combustion chamber. So ms, not ° or mm. (Although not necessarily a constant time bTDC, the optimum of that time is probably RPM-dependent too.)

But that raises the question: why 1.3ms bTDC? Do you have dyno charts to support that choice, or how else did you come to that value? The advancement your system gives should increase the power of the engine, as from 3kRPM onwards; by how much? I'm just asking, because your claimed timing (green curve) is quite an outstep from convention.

[Guesi]

In Wikipedia ist zu lesen, dass die Entzündung des Kraftstoff-Luft Gemischs unter Anderem abhängig von
Temperatur und des Kraftstoff-Luft Verhältnisses ist, ca. 1ms beträgt und im OT den höchsten Druck
erzeugen soll.

According to wikipedia the ingniton of the fuel-air mixture depends, together with other factors ,on temperature and the relation of fuel and air (Lambda factor), should be about 1 ms beforeTDC to provide the highest pressure on TDC.
That is why we try to keep it around that area of 1,0 to 1,3 ms..