No spark ajs twin model 20

Information relating to the Matchless G9 or AJS Model 20 500cc twin
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No spark ajs twin model 20

Postby Davidtalbot3 » Tue Oct 08, 2019 9:42 am

Hi again my ajs has been stored in a garage for the past 20 years it's in great condition I am not very knowledgeable in the classic bike scene as I am a new owner I have changed plugs battery but am still getting no spark from plugs any help would be great thanks again

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Re: No spark ajs twin model 20

Postby Duncan » Tue Oct 08, 2019 7:56 pm

Hi David, basic first question do you have a magneto or distributor?

If a distributor have you checked you are getting power to the points?

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Re: No spark ajs twin model 20

Postby clive » Wed Oct 09, 2019 8:00 am

If you have a magneto the very first step is to clean the points with very fine sandpaper or a points file. When standing for years the surface of the points corrode (oxadise i think) and will not allow a spark. Reset the points gap for 12 thou and then see if you get a spark at the plug.
clive
if it ain't broke don't fix

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Re: No spark ajs twin model 20

Postby bitza » Wed Oct 09, 2019 11:25 am

Check fuel to carb if you have spark at plugs a rough guide pour a spot of fuel into each cylinder replace plugs it should fire up and run for few seconds.

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Re: No spark ajs twin model 20

Postby Davidtalbot3 » Thu Oct 10, 2019 12:01 pm

Thank you for your replies I will check magneto and see where I go from there thanks again regards david

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Re: No spark ajs twin model 20

Postby bitza » Thu Oct 10, 2019 12:42 pm

If it's a coil system. Check all the connections,the points in the dissy. Especially the. Thin wire to the condenser for a break.condition. Of high. Tension leads and coil

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Re: No spark ajs twin model 20

Postby bitza » Fri Oct 11, 2019 12:40 pm

With the mag unclip one of high tension pick ups and clean the track refit and see if you have a spark if the engine runs ok from cold but then is pig to start when hot suspect the mag might. Need a rebuild.

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