'
Good fun also cool how many of us here had these crazy bikes as kids.
My best pal and I split on one in '72, used roller Mini like BM's above w/ no brakes but good tires for $10.
We scored a 60's McCulloch 2-Stroke Chainsaw engine for free and got it bolted in but had to pay $20 for a centrifugal clutch which seemed like a thousand then.
The 2-Stroker was way too much power but "luckily" chain and rear sprocket a slightly different pitch than clutch drive gear so chain would come off about 30 mph although gearing felt like it would've done twice that or more.
Yikes it was 50 years ago!
~ Pete