lavalette aml 50 /2 no spark

Alan Jackson /

turning over by pedalling I get no spark

if I connect a 12v battery that's quite flat (reading 9v) to the system I can get a spark at the plug ie open points, earth backplate and plug, and connect live on and off to points wire = spark

if I try with a flatter 12v battery reading 5volts I get nothing

whats the lowest voltage I should be able to connect like above to get a spark? a torch battery?

is this a good way of determining how healthy the ignition coil is?

Re: lavalette aml 50 /2 no spark

Doesn't mean your condensor is good. Replace it to be sure.

Re: lavalette aml 50 /2 no spark

I would suggest to test the condenser first

Clean the contact points

Clean the contactor for the HT lead (look on the drawing all the spring, button, holder and there is a contact spot on the coil)

Make sure the spark plug end of the lead is in good shape, the contactor for the plug at that end of the lead should have a spike that goes into the conductor of the lead.


When you clean the bits use some contact cleaner OR some brake cleaner OR alcohol (running type not drinking) and a metal file. Using abrasive cloth can leave behind bits of grit that can be problematic. ALSO do not use carburetor cleaner because it has lube in it and the lube will prevent good contact onyour electrical components.

Re: lavalette aml 50 /2 no spark

Alan Jackson /

I CAN get a spark at the plug if I supply the points wire with voltage

so nothing needs cleaning etc? but I did that anyway filed down to get shiny metal

my question is what is the lowest voltage I could supply to get a spark at the plug?

and I will get a new condenser

Re: lavalette aml 50 /2 no spark

Dirty30 Dillon /

You're trying to diagnose an issue that is most likely points/condensor but battery powering the HT coil.

You have shown is what you're working with in any of the threads. So diagnosing via post is kind of worthless.

Re: lavalette aml 50 /2 no spark


Try the condenser first - did you test it?

Testing the condenser (which is just a capacitor) is best performed with a old school multimeter set to ohms.

Disconnect the pigtail fronthe points and attach a lead to it, the other lead touch to the stator plate. The meter should drop to 0, then start rising again. Reverse the leads, and it should do the same again. That is a pass for the test.

A steady low reading means a shorted condenser.

No reading at all, means an open condenser.

A condenser is a 0.25 microfarad (approx) capacitor with high voltage and heat ratings. It absorbs the reverse kickback from the coil as the points begin to open. If the condenser is open, the points will arc over as they open up and the engine will have weak if any spark, because the coil's current falls off too slowly. If the points aren't all that old, but have massive contact buildup, it's going bad.

If it's shorted, it's the same as points that aren't opening at all.

ANY condenser will basically work, so one from a mid1960 car will likely fit in the magneto and will do the job.

For the coil, Marc Deschamps has one for the AML motor

Also the ignition points

Hope that helps (edited)

Re: lavalette aml 50 /2 no spark

Alan Jackson /

re the multiposting

I just saw someone testing their system with a torch battery and wondered what is the lowest voltage I can use to test my system

and is this a good way of testing the system

if people read my original post this is my question

the other thread is how to find a replacement system to fit my taper

totally different questions in my mind

I have two magsets, I have not tested the condensers because I do not have an analogue voltmeter

I am supplying voltage before the condenser at the points wire and getting a spark on both magsets

is that not telling me the condensers are ok?

I have a condenser off my puch I can try

Re: lavalette aml 50 /2 no spark

With the number of cycles you have I would suggest the ohm meter to be an excellent investment for your tool bench.

Just get a condenser from any old popular car or a different moped if you have a number of them that will fit in the magneto and substitute it for your (perhaps) dead one and give it a try if you do not want to purchase a ohm meter.

Testing with a torch battery is very iffy - you might have the voltage but not the wattage to generate enough for a spark. The magneto on your motor is rated at 6v 10 watts.

Re: lavalette aml 50 /2 no spark

Alan Jackson /

ok that's cleared that up thanks

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