Ignition Timing

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
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spookefoote1956
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Ignition Timing

Post by spookefoote1956 »

Am I correct for the model 18 1956 to set it to 1/2" BTDC fully advanced?
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Re: Ignition Timing

Post by SPRIDDLER »

spookefoote1956 wrote:Am I correct for the model 18 1956 to set it to 1/2" BTDC fully advanced?
Yes. Page 6 of Owners Manual!

http://archives.jampot.dk/book/Owners_m ... Manual.pdf
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spookefoote1956
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Re: Ignition Timing

Post by spookefoote1956 »

I've got an N1 mag on mine. Should still be the same points gap etc?
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spookefoote1956
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Re: Ignition Timing

Post by spookefoote1956 »

Just checked the timing again and that seems to be fine. I'm getting a good spark off the plug and fuel is going through. Won't start though, not even a fart. Any thoughts oh wise ones.
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Duncan
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Re: Ignition Timing

Post by Duncan »

Silly question, have you timed it on the correct stroke?
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spookefoote1956
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Re: Ignition Timing

Post by spookefoote1956 »

I think so. I put my finger in the spark plug hole and kicked over until it started to push my finger out. Surely that's under compression?
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Re: Ignition Timing

Post by SPRIDDLER »

Not enough info. I believe it hasn't run for 30 years until you have just recently reassembled it.
Is the plug getting wet?
Is it a good plug? (Although it sparks outside th'engine it may not when under compression).
Try tipping a teaspoon of petrol in the plug 'ole and then see if you get any firing.

Failing that.....
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Re: Ignition Timing

Post by StephenG80 »

Have you roughly got the pilot screw set right? ie about 1 3/4 turns out from fully wound it. Mine wouldn't start and that sorted it. With that mag you'll be on manual A/R, so presuming it is a pull out on the lever to retard ie cable going into top LH corner when looking at the points side- for starting you want it at about 2/3 retarded (at least that starts mine happily). Good luck :-)
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spookefoote1956
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Re: Ignition Timing

Post by spookefoote1956 »

Thanks chaps, Will try that tonight

By Pilot Screw do you mean the Throttle Adjusting Screw or the Pilot Air Adjusting Screw?
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Re: Ignition Timing

Post by Pharisee »

I can kick my M18 all day (from cold) and it won't start unless the carb is flooded and the throttle is held about 1/4 open. That has auto advance on the magneto which was set 1/2" BTDC on full advance. The air slide (choke) lever can be set anywhere from open to closed and it makes very little difference to the starting but fully open when running, obviously.
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