Suggest you contact TokyoCycling
http://www.tokyocycling.com/ to find an LBS where you can get an affordable Keirin frame. If you need help communicating ask for Tanaka-san at Kimi Information Center in Ikebukuro
http://www.kimiwillbe.com/. Tell her that the Irishman who mostly wins at Nakayama Keibajou (racetrack in Chiba) sends his yoroshiku.
Gambatte!