Piston Kit Forged Series for 4-StrokeForged 4-stroke piston is designed for each specific engine application and built to the tightest tolerances for the ultimate combination of performance and strengthDedicated forgings allow for optimized strength-to-weight ratioIdeal for multiple purpose ridingKit includes piston, rings and circlips'04-'05 Yamaha YFZ450 the stroke is 62.00 mm and compression ratio is 13.0:1.