No spark

[Furu]

Hello

I'm trying to restore my fathers 500 sport, it's been sitting in the garage for 19 years now with ignition issues.

I sent the stator for a overhaul to NLM and also ordered a new pick up and new transducers. I've connected everything to the bike according to the instructions supplied by NLM. My problem is that I still don't get a spark.

I've measured the output from the stator to the transducers and assured it gets power. When I've tried to measure the voltage output from the pick up I get a really small voltage, less than 1 V.

Does anyone know how large the voltage output from the pick up should be?

Any help would be appreciated, thank you!

[72degrees]

Did NLM supply their new style ignition system components or original type transducers and pickup?

Useful article here but no confimation of pickup voltage: http://www.motomoriniclub.nl/tech.html

The pickup is only a 'trigger' so I doubt the voltage needs to be very much. Someone who knows should be along later but when I was having trouble fitting a new NLM pickup I found my old red unit was giving about 100-150 mV (the non-functioning new style one gave half that voltage). I still haven't got round to fitting the replacement they supplied as it is running well on the new type box and coils and red pickup.

From my exprience, even with new parts the earthing of the components is critcal. Make sure there is a dedicated earth connection from the crankcase to the frame not just relying on the bolts. If possibly gather the earth connections for the transducers (or coils if the new system) to that same same earth point.

[72degrees]

Oh and I forgot to say hook up the "green wire" direct to the stator output so as to eliminate any ignition switch issues.

[Furu]

Thanks for the speedy reply!

It's the new style of ignition system, I was wondering if it could be some kind of ignition glitch. I'll definitely try to hook it up directly to the green wire from the stator, that was a great idea!

And if that doesn't do the trick I'll start looking at the earthing.

Hopefully she'll be running soon!

[EVguru]

The trigger voltage is something like 1.5v, but you would need an oscilloscope to check it.

[Furu]

I did another attempt in my quest for a spark. The earthing has a 0.7 ohm difference between crank case and frame. Connecting the green stator wire to the transducers didn't help. I unfortunately don't have a oscilloscope but I measured a 50 mV current coming from it. So I believe that the transducers get a signal, since I get voltage from the stator and the pick up. Does this mean my transducers are broken? I have the original grey ones, haven't tried them thou. Are they compatible with the NLM pick up?

[EVguru]

You can use the grey transducers with the NLM (or an original red) pickup, but you need to add a diode with the cathode (stripe end) towards the transducer.

Something that occours to me though.

If battery voltage is supplied to the transducers AND they get a trigger from the pickup then they will fail. That can occour due to a faulty ignition switch (or a well meaning auto-electrician!). Morini added a blocking diode to the loom on later bikes, so you could only ground the green wire (to stop the engine) and not supply battery voltage.

If this kind of fault was the original cause of the ignition failure, the same thing may have happened again.

To bench test a transducer connect the transducer blue wire (Earth; it's duplicated on one of the blades on top) to a 12v battery negative. Connect one side of a 12v bulb to battery positive and the other side to the green wire terminal on the transducer. The bulb should be unlit. Apply a voltage to the pickup input on the transducer (referenced to earth of course). Anything over about 1v should turn the bulb on. It will remain on even if the trigger is removed and will only go out if the 12v is diconnected. If the 12v is connected again the bulb should once again be unlit.

[George 350]

Paul,
That is a really handy bit of info - how come this/ why isn't this in any of the terch help sections?
Regards, George.

[EVguru]

Paul,
That is a really handy bit of info - how come this/ why isn't this in any of the terch help sections?
Regards, George.

Because I worked it out on the spot.

I bench test using an adjustable AC supply (variac; approx. 100 volt) which is potentially dangerous, so I wanted to suggest a safe alternative!

[DUGGIET35]

Hello out there, my Sei-V is also a reluctant sparker and I was pleased to find the info from Evguru from the Nederlands club, but there is a conflict.We are given warnings about the cataclysmic results of connecting 12v directly to the transducers but Evguru gives this as part of the test procedure - have I misread or missed something here?

Thanks for all the other info provided,
DuggieT35.

[EVguru]

Hello out there, my Sei-V is also a reluctant sparker and I was pleased to find the info from Evguru from the Nederlands club, but there is a conflict.We are given warnings about the cataclysmic results of connecting 12v directly to the transducers but Evguru gives this as part of the test procedure - have I misread or missed something here?

Yes.

At no point to I advise connecting 12v DIRECTLY to the transducer.

The TIC106 SCR is rated at 5amp continuous and will not stand being used to short circuit the battery.

It will however quite happily supply the <2amp required to light a tail light or inducator bulb. It would even survive a headlamp bulb.

[DUGGIET35]

My apologies, EVguru. I had clearly overlooked the current factor. I should have realised that the current draw by an external load was going to be much less than a dead short.

Thanks again, DuggieT35.