Exhaust valve assembly for a two-stroke internal combustion engine

A method of operating an exhaust valve of a two-stroke internal combustion engine, the engine comprising a cylinder and a piston movably disposed within the cylinder, the piston being movable along a cylinder axis of the cylinder in a reciprocating motion including an upstroke and a downstroke, the cylinder defining at least one exhaust port for discharging exhaust fluid from the cylinder, the exhaust valve being configured to cyclically obstruct the exhaust port, the method comprising:

• rotating the exhaust valve in a first direction for clearing the exhaust port before the piston uncovers the exhaust port during the downstroke of the piston, the first direction being opposite a direction of rotation of a crankshaft of the engine;
• and
• rotating the exhaust valve in the first direction for at least partially closing the exhaust port before the piston fully covers the exhaust port during the upstroke of the piston,
• said rotating of the exhaust valve relative to the rotation of the crankshaft at least partially counterbalancing the crankshaft.