Max A-weighted sound levels based on measurement at 50 feet from closest point to motorcycle (61-9-418): 1)manufactured before 1970--92dBA; 2)manufactured after 1969 but prior to 1973--88dBA; 3)manufactured after 1972 but prior to 1975--86dBA; 4)manufactured after 1974 but prior to 1978--80dBA; 5)manufactured after 1977 but prior to 1988--75dBA; 6)manufactured after 1987--70dBA.