Atlas Magneto Problem

The condensor (capacitor) has almost certainly failed at that age.  Usually the first symptoms are unwillingness to re-start when hot.  Yours might be beyond that.  They should be able to fire a spark over about 4mm.

There are electronic options and that will be the quickest way to get it back on the road.  People who have them usually praise them.  But you will then always have to rely on charging system and battery.  I love magnetos.  My 88SS is easier to start now I've put the magneto back.  And to my eyes it looks better.

The 'Easycap' capacitor can be fitted with care by the owner without needing a rewind. It might be worth a try.  But a good service will include re-magnetising and lubricating and generally replacing worn parts.

Dear Graham,

I have owned my 1965 650SS with a K2F magneto for 45 years. The magneto was overhauled for the first time some 10 years ago but failed withe usual starting difficulties when hot about two years ago. I wanted the condenser to be readily accessible thereafter so had Paul Wolf, the NOC’s magneto specialist, perform a comprehensive overhaul.

I can only say that the result was fantastic and I would not go anywhere else now - others may be cheaper but remember “buy cheap - pay twice”.

Unfortunately, with a similar problem, the MO1 magneto on my ‘53 Inter failed. As a result I had Paul Wolf comprehensively overhaul that one too - same fantastic result with easy access to the condenser.

Don’t even think of going anywhere else if you intend to keep your Atlas for some time is my analysis.

Regards,

Anthony Bolton

You can buy a small electronic gizmo that sits inside the magneto and takes the place of the condenser. They were less than £20.

Paul Wolf contact details are on this site under Technical Contacts.

The EasyCap is made by Brightspark magnetos.  Their website tells you more about magnetos than you will ever need to know. They used to refurbish them but I believe they don't do so any more.  The site gives fitting instructions.

As above , its likely that the Mag has failed.  Its equally likely that the plug caps have corroded and leads can also fail , I would check them for resistance with an ohm meter, before pulling the mag out. You could also clean the earthing brush.

For magnetos. Including At Brightspark site.   if you have a multimeter you can quickly confirm it’s electrical status and make your move from there.  Personally I would remove it, get it refurbished and continue using for the next 60 years.

Jon

I had the same problem with my magneto after several years of standing.

An old friend advised me to take the plugs out, close the gap until there wasn’t any clearance between the electrodes and give it several kicks. ( plugs earthed but not necessarily refitted)

I was very sceptical but tried it and when I reset the electrode gap low and behold a beautiful fat spark.

I bought the bike, a 1957 99 in 1962 one dropped a rod in 1970. I finally got it rebuilt in 2020 after a complete rebuild including the magneto. To be on the safe side I fitted a Brightspark condenser.
 

At the first kick there was nothing, one cylinder fired on the second kick and it was running sweetly on the third kick. It has started on the first kick ever since.
 

Try closing the plug gap first, nothing to lose and could save a lot of time.

I agree with Robert, the next easiest step is to clean the earth bush, situated under the screw on your nameplate photo, and it’s slip ring on the armature followed by new plug leads.

I never understood why the principal worked, perhaps our Al could enlighten me after all these years.

Best of luck.

Dick Hudson

Dear Members,

I should mentioned in my previous post that Paul Wolf included Brightspark condensers in the overhaul of my K2F and MO1 magnetos.

Regards,

Anthony Bolton

Please remember I am an electrical basics person-not a magneto person. But the idea of this 'repair' I never understood why the principal worked, perhaps our Al could enlighten me after all these year. The magneto is basically a coil of wire wizzing round in a magnetic field hence creates electricity in another coil of wire. if the magnetism is low then shorting the plug reduces the demand for it to self generate, if it does self generate then it might decide to work at full load/demand. So yes it is all magic!