Genuine Yamaha replacement keys can come as blanks with a number stamped on them. The number relates to the key profile, of which there were probably less than twenty in total.

The attached chart should show which lock number used which profile key.

I'm afraid that I don't have an equivalent chart that gives the Yamaha part number for each blank key profile. However, I am attaching a blank that I acquired myself a while back, in its original packaging. If you go to the CMSNL website and start typing the part number shown in my photo, you will get to a list of all of the keys and part numbers.

The keys are available from CMSNL, on fleabay and might even still be available from Yamaha. Obviously you will need to get the key cut, using the number on the barrel of your lock to determine the profile (a decent master locksmith should have all reference material needed).

  
 

I've done business with cyclekeysonline on ebay.

Keys cut to your code and delivered under $15.  I just searched by "Yamaha 2632" and it pulls him right up.  Not on a Yamaha blank though, I'm sure some would prefer the original stuff.

I think somewhere I have the list of key part numbers...  not sure if they are still valid but I will look for them