SO just what is the attraction of a Harley Davidson motorcycle? 'It has better pull with the girls than a Ferrari, and it's much cheaper,' said one member of the Hong Kong chapter of the Harley Owner's Club, or HOG. Fortunately, Miss Calgary Chinatown Pageant 1994 Elisa Wong, brought in to add the glamour, was out of earshot at the time, as was the energetic Angel Leung, assistant channel director of FM Select. They had gathered in Whampoa Garden yesterday with nearly a dozen Harleys to raise money for the Community Chest. The Hutchison Whampoa Property and Metro Broadcast promotion capitalised on Hong Kong's greatest passion - being photographed. For a small donation, one could drape oneself over a custom bike and take away a Polaroid picture for posterity. Draping oneself over Miss Wong, in town for the Miss Chinese International Pageant next month, was not allowed.