An internal combustion engine comprising: a crankcase having a first crankcase portion fastened to a second crankcase portion, the first crankcase portion being joined to the second crankcase portion along a first plane, the first crankcase portion having a first wall defining a first crankshaft support aperture, the second crankcase portion having a second wall defining a second crankshaft support aperture; a crankshaft having a first end portion, a second end portion and a central portion, the crankshaft being rotatably supported inside the crankcase, the crankshaft being rotatable about a crankshaft axis, the crankshaft axis being normal to the first plane, the first end portion being received in the first crankshaft support aperture, the second end portion being received in the second crankshaft support aperture; a cylinder block fastened to the crankcase, the cylinder block defining two cylinders, each of the two cylinders having a cylinder axis; two pistons operatively connected to the crankshaft, the two pistons being disposed in the two cylinders; a cylinder head fastened to the cylinder block, the cylinder block being disposed between the cylinder head and the crankcase; a crankshaft support defining a third crankshaft support aperture, the third crankshaft support aperture being coaxial with the first crankshaft support aperture, the second crankshaft aperture and the crankshaft axis, the central portion of the crankshaft being received in the third crankshaft support aperture; and at least one fastener fastening the crankshaft support to the cylinder block, the at least one fastener being perpendicular to the crankshaft axis and being disposed in a second plane, the second plane being one of coplanar with and parallel to the first plane. a crankcase having a first crankcase portion fastened to a second crankcase portion, the first crankcase portion being joined to the second crankcase portion along a first plane, the first crankcase portion having a first wall defining a first crankshaft support aperture, the second crankcase portion having a second wall defining a second crankshaft support aperture; a crankshaft having a first end portion, a second end portion and a central portion, the crankshaft being rotatably supported inside the crankcase, the crankshaft being rotatable about a crankshaft axis, the crankshaft axis being normal to the first plane, the first end portion being received in the first crankshaft support aperture, the second end portion being received in the second crankshaft support aperture; a cylinder block fastened to the crankcase, the cylinder block defining two cylinders, each of the two cylinders having a cylinder axis; two pistons operatively connected to the crankshaft, the two pistons being disposed in the two cylinders; a cylinder head fastened to the cylinder block, the cylinder block being disposed between the cylinder head and the crankcase; a crankshaft support defining a third crankshaft support aperture, the third crankshaft support aperture being coaxial with the first crankshaft support aperture, the second crankshaft aperture and the crankshaft axis, the central portion of the crankshaft being received in the third crankshaft support aperture; and at least one fastener fastening the crankshaft support to the cylinder block, the at least one fastener being perpendicular to the crankshaft axis and being disposed in a second plane, the second plane being one of coplanar with and parallel to the first plane.