Importing a motorcycle which is made for Japanese market is virtually impossible. The motorcycle must conform to the Environmental Protection Agency’s (EPA) regulations. EPA’s requirement is that you need to obtain a certificate or a letter stating that the motorcycle conforms to the U.S. standards. According to motorcycle manufacturers in Japan they are not able to issue certificates except in the rare cases where the vehicles are made for international market including the USA as most of the motorcycles are made for the Japanese market.
It is normally necessary to clear your motorcycle shipment as general cargo instead of unaccompanied personal effects even if you are moving from Japan.
Every country has its own restrictions and regulations concerning the import of motor vehicles. It is important that you are fully aware of restrictions and regulations of the country where you ship your motorcycle to.