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By jacobtue
#95764
Hi all... I have a question about sealing head and cylinder using Mr H's composite gasket. For some years I have been running my bike with an iron barrel using the compsite gasket and a smear of copper paste on both sides. It works super. Now Im changing to an alu cylinder (bigger bore). I want to continue using a composite gasket. But should I also continue using copper paste or change to aluminum paste. I have been warned against galvanic corosion when using copper. But is corosion really an issue considering oil/grease in the alu paste? best regards Jacob
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By Adrian
#95809
Swapping to an aluminium cylinder barrel makes it easier to get rid of the gasket altogether, you can use a (guided) hole saw to cut grooves in the joint face around the tops of the pushrod tunnels to use O-rings to keep the oil in. Bullet Whisperer has modified several engines this way.

A.
By jacobtue
#95833
Cranky, copperpaste, aluminumpaste ... it's like toothpaste, but greasy stuff for your motorcycle. Adrian, it's tempting to get rid of the gasket, but pro's and con's considred, my experience with the composite gasket from Mr H is good, and I don't have issues with an overheated cylinderhead, so I stick with the gasket solution. A good smear of copperpaste has given me a perfect seal, and the gasket can be re-used many times before replacement. The question is if the copper will cause a galvanic corossion or not. Because of the grease/oil mixed with the very fine copper particles, I believe it's harmless to the aluminum cylinder and head, but one can never know for sure unless it has been investigated thoroughly. Naturally my enquiry in to the subject begins here in this forum of technical knowledge.

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