A while back I gathered up the parts to re-create a Popular Science magazine project from '36, called "Power Bike". They show how to convert a bicycle to gas power (in the article, they used a 1hp briggs engine). I wanted a little more power so I bought one of those robbin 6hp overhead valve engines from harbor freight. I've still not got started on the project.
Now that I've seen the motor bike club, I'm thinking about taking the pre-war Hawthorn bicycle I have to the meet this summer & selling it & the other parts to help offset a little of what I'll probably be spending on a Simplex.
I'm probably 5 hours from Portland, & July is a slow month for ww2 reenacting, so I'll be there for sure.
Mike Sal