As Harley-Davidson Inc motorcycles roll into their 100th anniversary this week, owners and collectors are celebrating an American icon that has come to represent coolness and badness worldwide — at a growing price tag. This image costs buyers of a new Harley-Davidson $8,000-$25,000 and as much as $150,000 for rare, early models in Japan. “Many motorbikes look like Harleys, but a Harley sounds so different,” said Lin Todd, a former helicopter pilot who, like other Harley fans, revels in the ‘heavy-throated, muscular sound’ that other makers try unsuccessfully to imitate. Even among newer models, “Harleys hold their value better than any other brand,” added Mark Andrew, who works for a trucking company. He estimated that his fifth Harley, for which he paid $15,000 in 1998 and accessorised, could sell for up to $22,000. The company — founded in 1903 by William S. Harley and Arthur Davidson, and joined later by Davidson’s brothers Walter and William — finally embraced that image in recent decades as ‘bad’ became marketably ‘cool’ and rock n’ roll became mainstream.