An exhaust valve assembly for a two-stroke internal combustion engine , the engine having a cylinder block defining a cylinder and a piston movably disposed within the cylinder, the cylinder defining an exhaust port for discharging exhaust fluids from the cylinder, the exhaust valve assembly comprising: a shaft configured to be rotatably supported by the cylinder block of the engine, the shaft extending along a central axis ; a valve connected to the shaft and configured to cyclically obstruct the exhaust port of the cylinder, the valve having an inner surface and an outer surface , the valve being configured such that: the inner surface of the valve has a cross-sectional profile taken along a plane normal to the central axis; and the outer surface of the valve defines an axial curvature of the valve, the axial curvature being configured to have a radius (AR) that is greater than a radius (CR) of the cylinder, the axial curvature of the valve defining an arcuate axis , and the cross-sectional profile of the inner surface of the valve has a generally triangular shape defined by two sides of the inner surface converging at an apex ; the exhaust valve assembly being characterized in that : the arcuate axis is configured to be further from the outer surface of the valve than a cylinder axis defined by the cylinder in a plane normal to the cylinder axis and containing the central axis when the outer surface of the valve faces the cylinder. a shaft configured to be rotatably supported by the cylinder block of the engine, the shaft extending along a central axis ; a valve connected to the shaft and configured to cyclically obstruct the exhaust port of the cylinder, the valve having an inner surface and an outer surface , the valve being configured such that: the inner surface of the valve has a cross-sectional profile taken along a plane normal to the central axis; and the outer surface of the valve defines an axial curvature of the valve, the axial curvature being configured to have a radius (AR) that is greater than a radius (CR) of the cylinder, the axial curvature of the valve defining an arcuate axis , and the cross-sectional profile of the inner surface of the valve has a generally triangular shape defined by two sides of the inner surface converging at an apex ; the exhaust valve assembly being characterized in that : the arcuate axis is configured to be further from the outer surface of the valve than a cylinder axis defined by the cylinder in a plane normal to the cylinder axis and containing the central axis when the outer surface of the valve faces the cylinder. the inner surface of the valve has a cross-sectional profile taken along a plane normal to the central axis; and the outer surface of the valve defines an axial curvature of the valve, the axial curvature being configured to have a radius (AR) that is greater than a radius (CR) of the cylinder, the axial curvature of the valve defining an arcuate axis , and the cross-sectional profile of the inner surface of the valve has a generally triangular shape defined by two sides of the inner surface converging at an apex ; the exhaust valve assembly being characterized in that : the arcuate axis is configured to be further from the outer surface of the valve than a cylinder axis defined by the cylinder in a plane normal to the cylinder axis and containing the central axis when the outer surface of the valve faces the cylinder. <EOS>