I've had a friend buy a bike in Chicago and bring it back here so I only know the reverse. As far as I know used vehicles over a certain mileage, can't remember what, are duty free.
The bike had to go through a safety check which made sure certain things were standard on the bike. For example, the speedometer had to read in kilometres and his headlight had to be daylight running. I don't think it cost him that much since he drove there to pick it up. Most important thing is to get all of your information first and have the proper paperwork when re-entering your country. They are the ones that will give you the hard time.
