With a quantity of eight pieces, the Collet is the most used part in the Valve(s) diagram.
The most reasonably priced component used on the Kx450-e9f Kx450f 2009 Usa Valve(s) is the Seat-spring.
This schematic depicts all components used in the Kx450-e9f Kx450f 2009 Usa Valve(s) partslist.