This is a Complete set ( 4 ) Kibblewhite STD Size Stainless Valves and Kibblewhites Quality Viton Seals( 4 ). 2 intake and 2 Exhaust on Both Seals and Valves. You do not have to replace the Valve Springs to run the Kibblewhite Valves on the CRF450. If you do need springs though message me and I can get them for you at a extra cost. 

. 02-08 Honda CRF450R Kibblewhite STD Stainless Intake and Exhaust Valves

. 02-08 Honda CRF450R Kibblewhite Quality Viton Seals Intake and Exhaust