I buy almost all of my used Honda CB parts from the USA but occasionally look at what is on offer in Japan. I have been using a proxy buying service to buy vintage watches for many years on the Japan auction sites but vintage motorcycle parts are very difficult to buy as many are prohibited items (no international shipping). Smaller NOS items are usually OK and often good prices. Just for my own knowledge I contacted my proxy service about the gas tank set for sale. Here is the response.
Thank you very much for your email.
Regarding auction s1212271504, please kindly note that there is a high possibility this item cannot be shipped internationally due to shipping regulations.
Even if the gas tank is empty and contains no gas, an official inspection and certification are required to confirm that an item is completely free of any residue. Regrettably, we are unable to arrange or provide such certification on our end.
For this reason, if you choose to proceed with this purchase through our service, shipment would be limited to a Japanese address only.
Please also note that, in this case, an additional fee of 5% of the total Charge 1 and Charge 2 amount (excluding the plan fee) would apply.