Heli-coil it with the head in place. ERC
. fill the bore with shaving cream . Never thought of using a shop vac. Maybe try both.
. Barbersol? Gillette With lanolin? Foam....edge....foam.....edge..
What do you need Mazza I have a few gaskets lying around, happy to give you one. Also you can get parts pretty quickly from Graham at http://www.royalenfieldaustralia.com/spare_parts.phpRegards Charles