When you first posted this I confused it with the actual antique “CycleCars” of the 1920’s and assumed this was a rich man’s sport.
After watching the video you posted I see this is clearly not to case! That inspired me to do some more research into the “Cyclekart” phenomenon and have to say it’s pretty intriguing!
For a basic overview I’ll found this with internal links to follow>
http://en.wikipedia.org/wiki/Cyclekart
I actually have already independently slowly started working on a vehicle pretty close to these. Although mine is to be a bit larger using 26” Worksman wheels (already purchased), and will have a much different engine- So unfortunately it would never qualify for any actual Cyclekart club events.
Never the less I could see myself doing this someday!
Vintage swag is a plus!
Thanks for the post and please do take lots of pics!
-Kirk