g9 ignition timing

Information relating to the Matchless G9 or AJS Model 20 500cc twin
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sid nz
Posts: 40
Joined: Sun Apr 13, 2008 10:40 am
Location: north island NEW ZEALAND

g9 ignition timing

Post by sid nz »

hi everyone. i am trying to set the timing on my 1960 g9. i have made a plate with degree marks and put the tdc mark on the alt. i want to use a strobe light but need to know how many degrees bdc it sould be firing at.
thanks
sid
sid
Eric
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Posts: 1221
Joined: Fri Jan 01, 1993 12:00 am
Location: WEST MIDLANDS UK

g9 ignition timing

Post by Eric »

The recommended way is to measure the distance before top dead centre using a probe through the offside spark plug hole, in sensible countries that ride on the left.

Whilst the timing disc and the strobe light may appear to be the most precise way its not very practical as you have to remove the aluminium primary chain cover each time you want to do it.

The distance before TDC is 3/8" for the recommended method equivalent to 39 degrees for the method you want to use.

The points gap at the distributor should be set at 0.014" to 0.016" and make sure you use a probe with the end bent over or formed in such a way it cannot fall down into the engine.

The points gap for a magneto should be set as 0.012" to 0.015" and the advance lever should be set to fully advanced position.Edited by - Eric on 16 Dec 2010 12:52:41 AM
sid nz
Posts: 40
Joined: Sun Apr 13, 2008 10:40 am
Location: north island NEW ZEALAND

g9 ignition timing

Post by sid nz »

thank you very much
sid
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