Stud Length: 115mm. CVT Roller Sets. Aprilia RS 50 -1998 Cylinder and Piston OEM. Aprilia RS 50 99-02 Cylinder and Piston OEM. Aprilia RS 50 03-05 Cylinder and Piston OEM. This product is suitable for the Aprilia RS 50 99-02 (AM6) [ZD4PG / ZD4SE0 / ZD4TS0 / ZD4TSB / ZD4TSJ].