A 50cc moped engine in a BMX frame?! The MBK Crazy Bike was produced in very limited numbers in the mid ‘80s apparently to celebrate some sort of victory by the Motobecane BMX team. Where some ‘peds are only good at going round Thunderdromes, the Crazy Bike was designed to catch sweet air.
Nobody seems to know how many Crazy Bikes were produced in total, with numbers between 200 and 900 being thrown around. It’s also unclear if this least-sane of bike was every officially imported into the United States, although a few examples currently reside here and BMX Plus! famously put one on their cover in June, 1987.
According to CrazyBike.org, two versions were approved, a version specifically designed for BMX tracks that wasn’t homologated for road use and one that was, thanks to little fenders, mirrors and a dinky luggage rack.
The Crazy Bike couldn’t be a simpler machine, aside from the two-stroke engine and pedal/motor motivation, it was literally just a BMX bike. Check out the plastic fuel tank stuck in the frame and the rim-clamping bicycle brake calipers, not the kind of thing you’d want to rely on to slow you down from its presumed 35-40mph top speed.
Motobecane was founded in 1923 and was, somewhat confusingly, taken over by MBK Industrie with the aid of yamaha in 1984. I 1989 Yamaha increased its stake in the French company to 99% and manufactures scooters under the name to this day.
The nearest modern equivalent to the Crazy Bike would probably be the Sachs MadAss, although that bike lacks pedals in favor of sole engine power.