Original Yamaha Key.

[tommyardin]

If you give the Yamaha Key Tag  number to any of the bigger Locksmiths they should be able to cut one for you.

Same as that.
I gave the 'A' number from my tag to an internet key cutter and a short while later received 2 keys delivered to my in-laws home by post 4 days later that fitted perfectly.
The reason for having them delivered to a different address than mine is that no one will know where my Yamaha is especially if they have the ignition key number therefore access to a key.
Call me paranoid, but there are a lot of bike nicked that are chained up and secured without letting someone know where you bike is while they have access to the keys, if you going to do that it is much the same as leaving the keys in the ignition.