The Minarelli AM6 engine is widely known as a 50cc two-stroke workhorse,

But in its highly modified form, it has proven capable of extraordinary feats far beyond its humble origins. The engine pictured was used in the Buddfab streamliner, which set the 50cc land speed record in 2008, demonstrating just how extreme a small-displacement engine can become when engineering limits are pushed with precision and purpose.
In standard form, the AM6 is valued for its simplicity, compact size, and robustness. Found in many production motorcycles such as Yamaha, Rieju, Beta, Sherco, and Peugeot 50cc models, it became popular because it could handle sustained high rpm and accept extensive tuning. This made it a natural foundation for racing and record-attempt builds, where reinforced internals, advanced porting, custom ignition, and optimized cooling transformed it from a commuter engine into a high-speed specialist.
That potential comes with compromises. Extreme modifications dramatically reduce engine lifespan, require constant inspection, and eliminate everyday usability. The AM6’s original design was never intended for prolonged full-throttle operation at record speeds, meaning reliability becomes secondary to outright performance. In stock form it is dependable, but at record-spec levels, it demands expert maintenance and frequent rebuilds.
Fun fact: Despite holding a world speed record, the core architecture of the AM6 engine remains close enough to its street version that many internal dimensions are still recognizable—proof of how much hidden potential existed inside a simple 50cc design.