1947 model 18 tick over

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
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Charles.
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1947 model 18 tick over

Post by Charles. »

It starts fine, runs quite well [does pink a bit] but won't tick over slowly, even with the throttle stop screw fully out. I've fiddled with the air screw and don't know how many turns out it's meant to be now. Any clues to a starting point? It's a pain as the only way I can get it to run slow enough to knock it into gear, is to retard the ignition.
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Biscuit
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1947 model 18 tick over

Post by Biscuit »

Have you got wear between the body and the slide? I have the same problem, a coating of thick oil on the slide, I used steam superheater oil, cures it for about 30 seconds, not much use but it does prove the point.



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TommoT
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1947 model 18 tick over

Post by TommoT »

Well, for a start the throttle stop screw should not be fully out, i.e. completely unscrewed. The throttle stop screw is supposed to keep the throttle from closing completely. You should try to find a compromise between throttle stop screw position and air screw that allows the engine to idle slowly but surely. On an Amal Monoblock some manuals suggest starting with the air screw 1-½ out, then adjust throttle stop till idle just falters, then close the air screw till it falters again, then finalize adjustment with throttle stop till steady idle is obtained. This procedure is well described in many manuals and on many websites. For a very comprehensive and instructive website try: www.hitchcocksmotorcycles.com/Amal.

Good luck!

Tom M.
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Dave
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1947 model 18 tick over

Post by Dave »

Bob,
Tom's reply is correct although you probably haven't got a Monobloc carb fitted. The same procedure works for the 276 carb as well. Can you achieve a slow running engine with just the twist-grip? If not try the same again and retard the ignition. It could be that your ignition timing is too far advanced.
Cheers,
Dave.
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