Boyesen Power Reed Set - Yamaha 640

• Laboratory flow analysis proves Boyesen? dual-stage reeds out-perform standard reeds
• They permit greater flow velocity over the entire range of operating pressures
• Increased performance from start-up to top acceleration

Yamaha -- YZ 250 -- (1980, 1978, 1979, 1982, 1981, 1989); Yamaha -- IT 250 -- (1983, 1981, 1980, 1982, 1979, 1978, 1986, 1984, 1985, 1976, 1977, 1975); Yamaha -- YZ 465 -- (1980, 1981, 2008, 2004, 2015, 2014, 1985, 1984, 1983, 1988, 2003, 1982, 2006, 2013, 2002, 2005, 2007, 2010, 1986, 1989, 2012, 2001, 1999, 1987, 1990, 2009, 2011, 2000); Yamaha -- YZ 490 -- (1982, 1983); Yamaha -- YZ 400 -- (1979); Yamaha -- IT 490 -- (1981, 1982, 1985, 1983, 1984); Yamaha -- IT 465 -- (1983, 1982, 1981, 1980); Yamaha -- IT 400 -- (1979); Yamaha -- IT 425 -- (1980); Yamaha -- WR 250 -- (1989)