 However, many US models remained unsold for some years due to overproduction and an economic recession and brand new 1982 and 1983 models could still be purchased in 1987 at some dealerships.Like the contemporaries in its class the XS 650 has a 360° crank angle.This provides an even firing interval between the two cylinders, but also generates some vibration caused by the two pistons rising and falling together.