Head Gasket Thickness

Information relating to the Matchless G2 or AJS Model 14 250cc Lightweight
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Martin.S
Posts: 443
Joined: Sun Mar 18, 2018 12:02 pm
Location: Bristol UK

Head Gasket Thickness

Post by Martin.S »

Would any of you have a used head gasket they could measure its thickness for me - I'm trying to work out my compression ratio but I don't at the moment have an old or new gasket.
Thanks
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clanger9
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Joined: Sat Jun 20, 2015 9:38 am
Location: Chester, UK

Re: Head Gasket Thickness

Post by clanger9 »

My solid copper gasket is 1.2mm. I have a (new) composite gasket that's 1.7mm. I think composite gaskets squash slightly when fitted.
The compression ration on these bikes is mostly determined by the piston. There are three types that I know of: the standard piston is available new and gives 7.8:1 (or 8:1 with the 350 head, as used on the earlier CSRs). The later CSRs have a 9.5:1 piston (043647). The scrambler CS has a slightly-bonkers 10.5:1 piston (043748). The latter two aren't available new as far as I know.
1989 Moto Morini Dart 350
1993 Ducati 750SS
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Martin.S
Posts: 443
Joined: Sun Mar 18, 2018 12:02 pm
Location: Bristol UK

Re: Head Gasket Thickness

Post by Martin.S »

Once again Paul - Thank you - maybe in future I should just PM you as my personal oricle ;)
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