Is it worth experimenting to find if there's something else out there in the world that is a same sized fitment?
These guys sell 21mm gudgeon pins:
http://www.imdpistons.com/ They advertise them
on ebay for Honda CX500 so if you gave them some measurements they may be able to match something up or even make them according to the website!
If they're like rocking horse poop, get a batch made up and sell them all on ebay
