1974 R75/6 starter button loose

[Biebs]

Anyone have experience with this problem:

My 1974 R75/6 wirh the /5 switch gear on handle bars the starter button is loose - 2 set screws that hold it on are tight. Starter button works fine but if you touch it it wiggles around. I have had the bike for 5 years and just noticing this is there a way to tighten it up??