Where I am, anything with a motor under 50cc is not considered a motorized vehicle.
Discussion
50ccm ... hmm ... how much power can you get with that if you use alternative fuels with higher through-put? 🤔
Motorized two stroke scooters used to be very popular. Look up “Go-Ped” scooters. 49cc two-stroke motors with a ton of aftermarket parts including tuned exhaust pipes. Easy to make them go over 50 mph. Electric scooters and e-bikes are popular and how the law is written they technically not motorized vehicles because the motors on them are technically under 50cc. Pretty funny.
nitro and turbo, quite a lot, but that requires a lot of cooling as well... best you could do is maybe 70km/h on the flat... you'd need a tuned exhaust, spoked wheels, minimalistic frame to cut weight and decrease inertia
in bulgaria and several other countries they don't even count a 50cc motorcycle, it has to be registered and insured but no license is required to drive it