STD piston kit for Standard 71.00MM Fit Yamaha Models: BRUIN YFM250 2005-2006 Replacement Oem Part Number:  4BD-11631-00-Y0, 5XG-E1603-00-00,29U-11633-00-00,93450-17044-00   INCLUDES: STANDARD PISTON, PISTON RING KIT, PISTON PIN, CIRCLIPS