G80/85CS cylinder heads

Information relating to the Matchless G85 500cc Heavyweight, AJS 7R, Matchless G45 and Matchless G50
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G80/85CS cylinder heads

Postby mdt-son » Mon Nov 26, 2018 2:35 pm

Hi

For the 1960 season, combustion chambers were reworked for G80, G80CS and 500/650 twins. For 1964, the G80CS cylinder head was reworked again (026702 -> 031623).
I have seen pictures of the later one - there are some changes to the casting in the spark plug area - but what are the finer points? The late number indicates this was a modification made for the G85CS works machines at first.
Was the firing slot finally abandoned and a 10mm plug fitted?

Cheers,
Knut

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Re: G80/85CS cylinder heads

Postby bjorn » Tue Nov 27, 2018 10:38 pm

'65 CS cyl head.JPG
'58 and '65 CS cyl heads .JPG
Hi Knut,
Here are pictures of a 58CS and 64CS heads. I have two other heads similar to the 64CS, one off a 1968 G80CS and one off a G85. They all use 14mm plugs.

regards
Bjørn
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Re: G80/85CS cylinder heads

Postby Marty » Sun Dec 02, 2018 10:22 am

'64 and later had 1 3/8 inlet port standard and inlet valve has 5/16 stem also

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Re: G80/85CS cylinder heads

Postby ajscomboman » Sun Dec 02, 2018 10:38 am

Marty, you made any progress with the CS issues you were having?

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Re: G80/85CS cylinder heads

Postby Marty » Wed Dec 12, 2018 10:06 am

Different Marty. You are after the Australian, not the Kiwi. As an aside, I attended the Oz Jampot at Boonah, Qld. Met Marty and his problem children. I think he is very close to having both sorted, or as close as one can.

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Re: G80/85CS cylinder heads

Postby ajscomboman » Wed Dec 12, 2018 11:05 am

Marty wrote:Different Marty. You are after the Australian, not the Kiwi. As an aside, I attended the Oz Jampot at Boonah, Qld. Met Marty and his problem children. I think he is very close to having both sorted, or as close as one can.


Of course it is, sorry I should have realised by the way you're still beating that bloody animal!!!! :rofl: :rofl:

Still it's nice to hear that progress has been made. :)

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