Engine cylinder head copper gasket, for use on BSA models B40 & B44. O.E.M 41-0066 / 41-0638 / 41-0018.B40 & B44 Engine Head Copper Gasket, 41-0066 / 41-0018 / 41-0638. AA26KSKU: 41-0066 / 41-0638 / 41-0018£13.99PriceQuantity*Add to Cart