Could that be the front saddle off a Mini-Twinn tandem?
I really had to "shop around" to find an image with the crash rail attached--most examples don't have it. Only produced in 1968, I think you've got a bit of a jewel there. Might offer a neat alternative for a muscle bike build.
Oh. I flew the guy away. He was asking 50$ on it. And 20 miles away from me.
Thank you for you reply. I was curios about the seat.
Every day I have something new to learn about bikes.