
PROX Steel Exhaust Valve (manufacturer part number 28.6420-1): a robust replacement part designed for motocross riders seeking a reliable exhaust valve made of steel. Engineered to withstand the thermal and mechanical stresses encountered in off-road use, it is sold individually and fits into the cylinder heads of compatible engines.
PROX is recognized in the motorcycle parts world for its engine components. This valve provides a simple and robust replacement solution for the maintenance or restoration of a cylinder head. Ideal for maintenance work after a season on the track or for preparing an engine before reassembly, it is aimed at mechanics and enthusiasts who want parts suited for motocross competition.
Common compatibilities (examples): KAWASAKI KX 450 X (2026, 2025), KAWASAKI KX 450 (2026). Check the engine part number and dimensions before installation to ensure compatibility with your machine.