What is a key code?
A key code is a promotional code or a key used on games to see its legal or what not.
When you purchased your Yamaha Motorcycle, you should have received a tag attached to the key with a key code on it. Providing that key code and your vin number to a dealer will allow them to order a replacement key based on those values. If you don't have a key code, you'll have to order key blanks and have them carved identically to your existing key by a local lock smith.