"Whoa Black Betty - Bam-A-Lam" goes the song by Ram Jam - don't worry if you couldn't place the band, they were a one hit wonder. Now I've got some stuff here from a guy named John who is anything BUT a one -hit wonder, in fact, John's got a whole buncha killer scoot's he's taken the time to share with us at ChoppersRule. This first one, Black Betty, is a blown knucklehead! Let's let the builder tell the story:

I call this bike Black Betty{the blown bobber}. Frame is a Paugho  hardtail for rear belt. It runs both primary and secondary belts from
Phil Ross at Super Max products.{ he's an old chopper dude from the
sixties. He builds his products in his home shop just like it was done  before chopper stuff fell prey to corporate greed!} The motor is similar to the one in Jack Straw. Its internal dimensions are the same  3 5/8 x 4 3/8 .