PROX STEEL INTAKE VALVE/SPRING KIT YZ450F'03-09+WR450F'03-11

Replaces the OEM valves & valve springsSteel, nitrided valves for increased durability and less wear under extreme conditionsStronger valve springs deal with the extra weight of the steel valvesSprings are made from premium chrome vanadium steel for higher performance and durability at high rpmKit contains a set of steel intake or exhaust valves plus a set of specially designed valve springs; can be installed using the OEM retainers, bases and valve seals