I don't know why you want the office in Okinawa if you don't know where the bikes were registered. Okinawa is just one of the prefectures in Japan, and definately not a central office.
But the phone number is +81-98-877-5140 if you want it.
I doubt that anyone would have data for particular bikes that were deregistered and exported 10 years ago.
I think your best bet would be to contact Honda through Honda UK.
To get a shakensho (registration document) reissued, you need to know whose name they were registered in.
While I can't be 100% sure, I don't thin the Bros 650 was sold in Japan 10 years ago. Due to licensing restrictions 750cc was usually the next class after 400 at that time. So, the may have been imported from somewhere other than Japan.
This Honda website in Japanese gives the specs. The bike weight is the part marked kg in the specs.
This site gives the gross vehicle weight, however it is not an official Honda site.
Last edited by Chris in Tokyo; 6 Aug 2007 at 09:52.