The City, in defending against a lawsuit brought by the family of a San Francisco musician who died after riding the Cyclone last year, is claiming that Keith Shirasawa should have known that the roller coaster was potentially fatal. While riding the Cyclone on his birthday in July 2007, 53-year-old Keith Shirasawa fractured three neck vertebrae and died four days later after complications from surgery. His lawyers contend that the Parks Department is at fault for not regularly inspecting the landmark ride. But the city claims that “any and all risks, hazards, defects and dangers to the extent alleged are of an open, obvious, apparent and inherent nature known and should have been known to [Shirasawa],” according to court papers obtained by the Daily News.