1955 G3ls magneto

Information relating to the Matchless G3 or AJS Model 16 350cc Heavyweight
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Tazmantic
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1955 G3ls magneto

Post by Tazmantic »

Does this cam ring look right? Only ask as the points are open for 3/4 of the cam and only closed for 1/4

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Groily
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Re: 1955 G3ls magneto

Post by Groily »

It is absolutely normal, yes. Correct for the mag, correct for the bike.
Yves.Astein
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Re: 1955 G3ls magneto

Post by Yves.Astein »

Jupp, looks like the one I have installed.

Yves
Yves.Astein
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Re: 1955 G3ls magneto

Post by Yves.Astein »

Its normal, that its open for so long. I was also a bit insecure about that. Just make sure you set the timing on the opening slope and not the closing slope. I wasn’t paying attention to the rotation direction and did it wrong the first time. Just got some backfiring when I tried to start it.

Yves
Groily
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Re: 1955 G3ls magneto

Post by Groily »

Classically, the dwell period - points closed - on a rotating armature mag will be c 100°.
On a twin cyl camring, the dwell remains the same for each cyl, so 80° of 'points open' on the ramps is standard. The ratio of Open:Closed for them is, as a general rule of thumb, 0.8:1.
On a single cylinder camring, like on our NC1s, the same c 100°:260° as on the face cam version applies.
Apart from a few experimental ones created by folk wanting to convert face-cam instruments to twin cylinder operation, there are no twin cyl camplates.

As far as rotation is concerned, camplates are mostly marked L or R. This one's an L. Some, like in the pic here, are notched to take the advance and retard plunger on either side for tight or slack advance, some aren't. Usually, a plate can be renotched and repositioned to reverse rotation if need be, if parts are hard to come by. Which they increasingly are. There are far more Ls than Rs out there . . .

All a bit anoraky, I know.
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clive
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Re: 1955 G3ls magneto

Post by clive »

Rather than anorak call it specialist knowledge sounds better, a number of us need help with the electrical stuff.
clive
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Tazmantic
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Re: 1955 G3ls magneto

Post by Tazmantic »

Thanks much appreciated 👍
Everyday’s a learning curve.
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