Not having seen exactly how the one on your bike is broken off, it is hard to tell what kind of fix will work. BUT, if there is enough of a stub left to see you can fix it... drill a small hole in the center of it and screw in a stub or even a small screw. Fixed one of mine that way and rode it for years with no further problems.
2013 Indian Vintage Chief FE... #7 of 25
2011 Victory Vision Tour Premium...