PEABODY – A 39-year-old Salem man was flown to the hospital with potentially life-threatening injuries after a motorcycle accident in a Route 1 parking lot in Peabody Tuesday afternoon, State Police said. The man was riding a motorcycle in the parking lot of the Cabaret Lounge on Route 1 South in Peabody when he hit a retaining wall, according to State Police Trooper Thomas Murphy. Murphy said the man was not wearing a helmet at the time of the crash, which occurred at 4:30 p.m. Tuesday. The man was taken by helicopter from Kennedy Field in Peabody to Tufts Medical Center in Boston. Murphy identified the man as a 39-year-old Salem resident and said the injuries were “very serious ? potentially life-threatening.”Murphy said the accident reconstruction team was at the scene and the cause of the accident and whether alcohol may have been a factor in the accident was under investigation.