The drilled stud that holds the tank on my RS125 was making me crazy. So, today I grabbed a piece of free-cutting steel and made a replacement. It is not perfect but much better than the part it replaces. This one is drilled trough the middle to lighten it, the next one will be made from 7075.
After thinking about it for a while, I think titanuim would be a better materual for this part.