Hi, as far as i concern Kudat is a small town and tourism not really kick off despite being tourism venue. I dont think there is a rent a motorbike company in town. But for saying that, you may want to venture into Marina Yacht club and try to minggle with the yachtist community as most of them are English or Oz, they are very accommdating who knows they may lent you their bike for a day.
Anttoher option is u might consider spend 1 or 2 nights at the tip of borneo. Many locallly runs chalets are available