Outside Tokyo, up in Saitama prefecture, the police use Honda Super Cubs, 50cc and 90cc, for local patrols. Unlike in downtown Tokyo, where these tasks are usually done on bicycle or on foot, the more rural Kobans employ the the convenient Cub.
Of course, these aren't the only motorized bikes the police use. Honda high perf 1000cc "crotch rockets", with front and rear hard shell carriers, GPS based navi computers, mobile traffic light controllers, wifi cams, telescoping strobe lights, and high pitched engines that sound more like a product from General Dynamics than by HMC, these bikes give the appearance of a sharp edged, futuristic version of the old police Harley Electraglides. We'll try to get a pic of one of those soon. Hopefully not from over the shoulder!