Hello, you could buy it directly from Japan auction, many times i saw top end kit rebuild
many website could help you to buy and send if your japanese language skill its not very good, there are plenty i like to use http://buyee.jp for example.

Or you can also ask some shops to find it and send it , Dmr japan for example is very nice guy who helped me for some parts, and you get bills from his shop, witch is usefull to prove you changed part if you need sale your bike in futur.

Take care.