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Just for fun I checked the pulse coming out of the red pick ups and got about .320 AC of a volt on both sides while cranking with the electric start. It is not constant but just an intermittent AC voltage that appears every 2 seconds.

Intermittent AC is what you would expect. A two second firing interval on a 4T twin at starting speed sounds about right - or is it a bit 'slow' at equivalent to a cranking over speed of 15 rpm (maths isn't my strong point)? I've measured 1500 mVs on the red pickup leads but that was at idle, so at starter motor speeds that may be significantly lower as Evguru pointed out. I've no idea if it's a linear relationship to rpm.

If you can read German look at this. The charts give an idea of what's going on if you don't.
http://www.motomoriniclub.nl/zuendung.pdf

Have you ever had it running?

Borrowing a known good transducer would be a good next strategy. I' could have a dig through my box of ignition bits but a) I need to keep the two I took off when doing the NLM module conversion as spares to take to hill climbs in case that fails and b) they are all 350/250 ones.

72degrees wrote: A two second firing interval on a 4T twin at starting speed sounds about right - or is it a bit 'slow' at equivalent to a cranking over speed of 15 rpm (maths isn't my strong point)?

D'oh! Doesn't spark every revolution you TC! So more like 60 rpm? The electric start Strada (envious) at the VMCC meet the other night sounded to be turning over that slowly on the starter (though it started OK).

I wish that I could find something wrong or obviously wrong but I checked again the green wire with all disconnected right from the fuse box and I get 208 ohms to ground and while cranking I get about 28 to 30 volts AC on the green wire . I checked again the voltage coming out of the red pick ups and I got .396 of a volt AC on one and about .402 on the other . Everything is just too consistent to really suspect anything. If anyone has some ohm meter figures on these ignition boxes with the red dot on them let me know and I will compare my figures with yours . Mine are posted above.

I think the only diagnostic for the transducers apart from a substitution test is the method shown by Evguru in his Youtube video.

The heart of the transducer is the thyristor and just a resistance value probably isn't going to be much help (though it might confirm the integral coil is OK).

It is beginning to sound like both transducers are duff, which isn't unknown. You could consider acquiring a Lambretta/Vespa unit as a test only device. They apparently work fine on a 350 but presumably the timing curve would be wrong for a 500 - however, it would confirm the integrity of the rest of the system if you could get a spark out of it. In fact, I suspect that as you have a matching pickup it might even start on the one pot. At £15 free p&p it's worth a punt and you could probably sell it on to a 350 or 250 owner once you have identified the problem, though apparently you could fit two and compensate by adjusting the static timing. Having identified the transducers as the problem I'd be inclined to go for a NLM 'transducer pack' (module and HT coils) conversion (you can keep the red pickup if it is known good).

http://www.ebay.co.uk/itm/361885037858

...or even cheaper http://www.ebay.co.uk/itm/Vespa-Ignitio ... 1438.l2649...

Ming wrote:...or even cheaper http://www.ebay.co.uk/itm/Vespa-Ignitio ... 1438.l2649...

If you can wait 10 days while it is posted from India and it's £5 extra for postage. I might get one in as spare though. I've mounted the NLM module on both bikes so that swapping back to transducers isn't too major a job. Almost a side of the road fix (along with the spare pickup I carry on long trips). Carrying a spare stator is going a bit far though

There is one way to burn the two tranducers in one moment: a conection to their green ports to 12V (red/brown cable) just for less than a second. This might have had happend at any moment in the past. So trying other transducers to me as well seem´s to be the way to continue

norbert wrote:There is one way to burn the two tranducers in one moment: a conection to their green ports to 12V (red/brown cable) just for less than a second. This might have had happend at any moment in the past. So trying other transducers to me as well seem´s to be the way to continue

Good point well made!

Two things need to happen to burn out the ignition boxes.

One is that they need to be supplied with battery voltage, but that won't cause them to fail unless they also get a trigger signal. I recall that Morini were incorporating the protection diode by the time of the 500 to prevent a faulty ignition switch at least from incorrectly supplying battery voltage to the ignition.

It is not possible to check the ignition boxes with a multimeter, which is why I thought up my first test. https://www.youtube.com/watch?v=CWgLYidtHVw

The ignition switch and kill switch need to be eliminated. Check the ignition voltage with the alternator connected, not open circuit, to make sure nothing is shorting it out.

Well, I did the test and the light stayed on with a battery first then I tested it with the bike's own red pulse coils and the light came on again and stayed on. I then checked the AC voltage coming out of the ignition coil and it was putting out a pretty solid 35 volts AC after I charged the battery that I was using. I'm stumped . Everything seems to check good and consistent . Not a bit of spark even in dark room and I cannot even get it to shock me when I hold the plug in my hand.

As Evguru suggests the stator ignition winding output may still be being shorted out somehow, or possibly the transducers earth connection is bad. Have you checked the point at which the blue wires from the transducers are earthed to the frame and that there is an earth wire from a top rear crankcase screw to the frame. The engine should make good enough earth just from the mountings but if the frame has been repainted or powder coated it may not. I always run that engine earth wire from the crankcase up to the same screw that the transducer blue wires go to (though that may be easier on a 250 than a 500 as the transducers aren't under the tank). Have you checked the AC from the stator when given a really brisk lunge on the kickstart?

Time to eliminate the machines own wiring harness and minimise the ignition circuit to just one of the cylinders by hooking up the green stator wire direct to one transducer (if you haven't already tried that). If still no joy I'd try a Vespa unit. Then borrow a definitely known good pickup.

If you are not miles and miles away from NLM I can recommend taking your ignition components to be tested on their diagnostic rig which checks the whole system on a 'dummy' engine and allows for quick substitution tests, without having to take the entire bike.

Anybody mentioned leads and plug caps? Have the leads been unscrewed and a check done on the output of the coils?

MickeyMoto wrote:Anybody mentioned leads and plug caps? Have the leads been unscrewed and a check done on the output of the coils?

You have now. Stranger things have happened and it is possible for the leads not to be screwed on to the 'spike' in the transducer output properly.