Magneto: from manual to auto advance

Information relating to the Matchless G9 or AJS Model 20 500cc twin
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Re: Magneto: from manual to auto advance

Postby Expat » Fri Feb 09, 2018 2:33 pm

Interesting general info Bill, thanks for posting.
Keep shiny side up.

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Re: Magneto: from manual to auto advance

Postby sunnybob » Fri Feb 09, 2018 3:01 pm

Wow..it's a lot of power for a 60w generator bike :-(

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Re: Magneto: from manual to auto advance

Postby g5wqian » Sat Feb 17, 2018 6:52 am

on my twin i just retard the ignition when i kick it over for starting and then for riding i leave it fully advanced and it will go anywhere like that .
there may be the rare occasion that i will retard ignition if i am going up a steep hill and i feel the engine is going to start pinking .

i ride the bike once or twice a week for distances of 50 to 150 miles i had black plugs at times but i tried N3 N4 and N5 champion plugs and found that the N5C worked the best .

its all well and good wanting auto advance but if you have a dynamo they can suffer from getting oil into them from the timing case and if you encounter this it happens over a period of time without you knowing , and then you end up one day with a flat battery and no charging .
with a magneto the engine will still be running to get you home but if you have a distributor ignition its going to conk out on you .

used 18d2 distributors for the fiat t500 126 [650cc engine] are available on ebay most of the time and there are plenty of spare parts around for them , you may find reconditioned distributors for sale in poland because the cars are extremely popular there and being that we have many of our polish freinds who work with us these days i am sure someone could obtain a reconditioned 18d2 for you from poland very cheaply , they do raced up versions also because they also race these engines .

most of the polish lads have a cheap or even free system of transportation to get things sent and returned back because they use it themselves , but it is easy enough to use DHL or YODEL throughout europe .

myself i am sticking with the K2F and points , it was reliable for my father in the 1950s and is no different for me now , the price of parts may be higher but one set of points will last many years and the condenser can be replaced with with a modern replacement kit ..

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Re: Magneto: from manual to auto advance

Postby Duncan » Sat Feb 17, 2018 6:43 pm

Ian were you thinking of the Marelli distributor used on Fiat 500's, here is a modified one before being fitted to my G12, its the lower part of the distributor needs to be modified to take the drive gear:
DSCF2004r.jpg

DSCF2008r.jpg

They used to be plentiful but are now getting difficult to find at sensible prices.
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