Magneto

Yes,  you will need a magneto sprocket too as it uses a taper fitting.  The Early SS bikes used the Distributor and I have used one for 30 years with an Ei booster from Pazon or Boyer . I dont think I would change to a mag unless a fully recon one .

A Magneto could cost many hundreds, you could end up with dissimilar timing due to mag ring wear. Magnetos have smaller plug gaps as lower plug voltage. I sell an 18D2 kit that gets rid of the  dizzy rota, and give you wasted spark ie there cannot be any difference in the timing between both cylinders. This sytem insists on 12V so another up grade to the bike. The 18D2 do wear and some of this needs sorting when fitting electronic. Also the original coil ignition (and electronic) need a good battery/chargeing system. Fitting a magneto allows you to get sloppy with battery charging, hence running out of light when most needed.

Your choice!

As our esteemed Mr Oz says above, wear on the cam ring is to be expected on a mag that will be at least 60 years old by now.

If so, and a new one is needed- and available- expect some serious wallet pain. I remember going to Kays of Ealing (just ask Mr Oz!) and buying one. Seven pounds please, said the guy behind the counter. "OW MUCH?" I almost screamed." You're not paying for what's there, but what's been taken out. The machining for the cam profiles has to be spot on, and for a twin its twice the work".

Well it was 1970....

In favour of the magneto...after 20 years of RITA, I'm delighted to have my K2FC back again.  The bike starts just as easily (even in winter) and looks better to my eyes.  No more worries about battery charging and lots of electrical connectors, and I can now remove the spaghetti from battery to switch to ignition to coils to earth.

But this bike originally had a magneto.  Whether I'd do it if it originally had coil ignition, with wiring and coil brackets etc all fitted by Norton is another matter.  The real benefit of the mag was reliability when robust miniature 12v batteries and alternators that could keep then charged in city traffic were unavailable.  None of that applies if you originally has coil ignition.

Indeed, a very honest aprasal. As an advocater of the RITA and a 'disliker' of the magneto, I am impressed by a 20yr aprasal. Magneto-good chance of timing inaccuracies, small plug gap due to lower spark power. Sloppy battery charging allowing sloppy attention to lighting/stop lights etc. COIL ignition (RITA is in effect traditional coil) timing between the cylinders is the same. higher power at the plug, reliance on the battery/charging so lights are more assured. Your choice.

BUT I get a lot of questions about fitting 'Electronic Ignition' to magneto bikes. There is a mith that E I is the answer to a 'maidens prayer' , when told about the potential cost, reliance on Dynamo/battery charging and available power, fitting of an ignition switch extra wiring, it suddenly seems less of an answer. Until the cost of a magneto rebuild kicks in!  Your choice.

If you are not worried to much about cost I've been impressed with the new BTH mags.

AHA BUT they are not a real magneto........

RGM Norton have many choices of magneto sprockets try this one1269A

A 59 99 came originally with an 18d2 distributer - I know because I have one.

I fitted a new bush inside the body of the distributer and then fitted electronic ignition (boyer) and have never looked back since - that was 7 years ago and the engine starts and run beautifully everytime.

Why alter it from original?