Cal. Veh. Code § 25451

Any motorcycle equipped with one lighted acetylene headlamp complies with the provisions of this code concerning lighted headlamps on motorcycles when the acetylene headlamp is fitted with a clear plane glass front and a bright six-inch spherical mirror and a standard acetylene one-half or five-eighths foot burner, projecting sufficient light ahead to reveal any vehicle, person, or substantial object upon the roadway within a distance of 115 feet.