You need to talk to a Velocette owner! Fortunately I was one for many years. They use a simple copper ring as a head gasket, which sits on the top of the cylinder liner, in a recess in the head, clamped down with four long studs. To reuse the gasket, heat to cherry red, then quench in cold water, which softens them. They are actually laminated and can be reused many times, until they start to delaminate - just so you know!