Mtes, better transfer your license to a Japanese one right away cause you are riding illegal, anybody living and working in Japan for more than 6 months needs to do so, if you are caught you will be busted. They changed the laws here a couple of years ago. Its actually not that hard especially if you are from Canada....no more international licenses for non tourists...sorry

As for bike rentals in Japan, its just not done except for in Okinawa which is a tourist place kind of like Hawaii and has many US army dudes stationed there. Car rentals are fine, but have never seen bike rentals except for Okinawa.