Manufactured by Namura Kit Includes piston, rings, pin, clips you get exactly what is pictured Cast piston has super-high silicone content for additional strength Piston skirts are Molybdenium Teflon coated to minimize resistance/wear and provide extended life Piston dome is anodized for superior heat resistance and longer lifespan Kit is for .020 over bore size 40.50mm Piston is 40.46mm Compression ratio of 6.0 1 Made in Taiwan Fits 1981 Yamaha PW50 1982 Yamaha PW50 1983 Yamaha PW50 1984 Yamaha PW50 1985 Yamaha PW50 1986 Yamaha PW50 1987 Yamaha PW50 1988 Yamaha PW50 1989 Yamaha PW50 1990 Yamaha PW50 1991 Yamaha PW50 1992 Yamaha PW50 1993 Yamaha PW50 1994 Yamaha PW50 1995 Yamaha PW50 1996 Yamaha PW50 1997 Yamaha PW50 1998 Yamaha PW50 1999 Yamaha PW50 2000 Yamaha PW50 2001 Yamaha PW50 2002 Yamaha PW50 2003 Yamaha PW50 2004 Yamaha PW50 2005 Yamaha PW50 2006 Yamaha PW50 2007 Yamaha PW50 2008 Yamaha PW50 2009 Yamaha PW50 2012 Yamaha PW50 2013 Yamaha PW50 2014 Yamaha PW50 2015 Yamaha PW50 2016 Yamaha PW50