Picture of Marin Hinkle Wiseco Yamaha XT TT SR500 76 81 121 CR 3445XC Piston kit. The Wiseco team has remained at the forefront of powersports performance through every era and evolution, including the development of high performance 4 strokes. Today, Wiseco's forged 4 stroke pistons are designed for each specific engine application and built to the tightest tolerances for the ultimate combination of performance and strength. Proven at every level of riding, Wiseco 4 stroke pistons are ready to deliver the power and reliability you're looking for. This Part Fits: Year Make Model Submodel 1978 1981 Yamaha SR500 Base 1976 1981 Yamaha TT500 Base 1976 1981 Yamaha XT500 Base