Where do I go, where do I go, where do I go now?

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
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spookefoote1956
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Re: Where do I go, where do I go, where do I go now?

Post by spookefoote1956 »

Taid could you kindly explain ignition insulation please.
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bitza
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Re: Where do I go, where do I go, where do I go now?

Post by bitza »

I think he means that the plug gives a nice fat spark when lying on cylinder head and you kick the engine over, but when fitted it is the ceramic insulation is breaking down and the spark goes to earth . Just my thoughts on this .
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spookefoote1956
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Re: Where do I go, where do I go, where do I go now?

Post by spookefoote1956 »

Thanks bitza
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Taid
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Re: Where do I go, where do I go, where do I go now?

Post by Taid »

spookefoote1956 wrote: Sat Oct 01, 2022 3:05 pm Taid could you kindly explain ignition insulation please.
All through the high tension system the insulation could go dodgy and let the power leak away when the voltage reaches a high enough level .. when the plug is sitting, as bitsa says, on the cylinder head the plug may fire easily, but when under compression it requires more volts, which the insulation (Somewhere,, not necessarily the plug) can't handle ..

Sorry, I find it difficult to explain .. maybe the plug tester wasnt the best example ..
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bitza
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Re: Where do I go, where do I go, where do I go now?

Post by bitza »

If the damn thing wo'nt fire up as normal, if all settings are correct , it's worth trying an old wheeze, remove the plug and pour a drop of fuel say a tea spoon down plug hole fit the plug if all settings are ok it should fire up for a few seconds , just a rough and ready test .
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Re: Where do I go, where do I go, where do I go now?

Post by Greybeard »

I hesitate to get involved, but when youre trying to start it, is it wetting the plug, suggesting no spark? Or is the plug bone dry suggesting a fuelling problem?

If its down to a lack of spark then I'd do the easiest first and work through - new, non-resistor plug (making sure its not a fake), new plug cap (non-resistor), plug lead (simple copper cored), slip ring clean, good carbon brush in the pick up (if you can draw with it it's too soft) if you can check the safety screw gap in the mag isnt set too small which might encourage the spark to jump internally instead of at an under compression plug. A long shot but still worth a check as it costs nowt.

All this assumes of course that the valve/ignition timing etc is correct which i think youve already done. They are such a simple engine and will generally run until theyre on their last legs so it cant be much thats stopping it.

Steve
bitza
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Re: Where do I go, where do I go, where do I go now?

Post by bitza »

Useful information ,check the simple stuff first.
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Re: Where do I go, where do I go, where do I go now?

Post by spookefoote1956 »

Don't laugh.... yet. Sprocket or belt cog attached to outer clutch basket. Starter motor mounted above. Job done!
starter.jpeg
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Hail Joe Lucas ............ Prince of Darkness!
All my bikes are original........ to me!
"Creativity is your intelligence having fun" Albert Einstein
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spookefoote1956
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Re: Where do I go, where do I go, where do I go now?

Post by spookefoote1956 »

Greybeard wrote: Sun Oct 02, 2022 5:38 pm I hesitate to get involved, but when youre trying to start it, is it wetting the plug, suggesting no spark? Or is the plug bone dry suggesting a fuelling problem?

If its down to a lack of spark then I'd do the easiest first and work through - new, non-resistor plug (making sure its not a fake), new plug cap (non-resistor), plug lead (simple copper cored), slip ring clean, good carbon brush in the pick up (if you can draw with it it's too soft) if you can check the safety screw gap in the mag isnt set too small which might encourage the spark to jump internally instead of at an under compression plug. A long shot but still worth a check as it costs nowt.

All this assumes of course that the valve/ignition timing etc is correct which i think youve already done. They are such a simple engine and will generally run until theyre on their last legs so it cant be much thats stopping it.

Steve
Morning Steve. The plug is wet and the mag is a reconditioned one from our beloved spares dept. I've order a new NGK non resistor cap. I will check the carbon brush today.
Hail Joe Lucas ............ Prince of Darkness!
All my bikes are original........ to me!
"Creativity is your intelligence having fun" Albert Einstein
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Re: Where do I go, where do I go, where do I go now?

Post by Greybeard »

I daren't imagine what you've got planned with the sprocket outside the clutch :shock: Please think again. The NHS is already snowed under ;)

Steve
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