Originally Posted by
since6
Looks like a foot operated "Aaaarooogaaah" horn on the drive side foot board.
Before the internet and video games this was what was known as a hobby, almost all guys of your grandfather's generation had them involving building things with tools their skills and minds. It's how the bike industry, auto industry and airplane industry all got stated, people with a passion/curiosity for something working on their hobby after their jobs and the kids were in bed.
Wonderful, and make sure you explain this to your kids, get it running .
I am of a generation that builds things as well. My grandfather was born in 1899. I was born in 1956. I do appreciate the work and ingenuity that went into this, my son is a student of mechanics. He is the guy all his friends go to to fix their cars, bikes, hifis and musical instruments. We will take care of it.