Cam differences

Information relating to the Matchless G12 or AJS Model 31 650cc twin
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LynP
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Posts: 335
Joined: Mon Jan 01, 1990 12:00 am
Location: GWENT UK

Cam differences

Post by LynP »

Hi, I am changing the exhaust cam on my 1961 G12. The old cam which I know to be correct for my engine needs replacing and I have a good used one. I have checked the profiles of the lobes on both cams which seem the same, but the flat end of the shaft that drives the oil distribution unit does not go all the way across on the one I want to use, it has a gap in the centre. On the old cam that drive goes all the way across. I would like to know if I can use this cam and also if there are other difference in the various years of cams I should be aware of including Woodruff key position etc. (I am aware that a modified cam was fitted from 1959 on). Thank you, Lyn
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dave16mct
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Posts: 3234
Joined: Mon Jan 01, 1990 12:00 am
Location: LANCASHIRE UK

Re: Cam differences

Post by dave16mct »

I haven't seen a cam that has a flat with a gap in the middle but I can't think why you can't use it. It only has to turn a small alloy oil distributor. Can't be much force needed for that.
Dave.
LynP
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Posts: 335
Joined: Mon Jan 01, 1990 12:00 am
Location: GWENT UK

Re: Cam differences

Post by LynP »

Thank you Dave. I had the same thoughts about the force involved and like you I have not seen one with a gap before, I even wondered if it was a genuine AMC one. Maybe someone else has seen others like it. Best regards, Lyn
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