Way back in the 60’s Honda managed with this little 50cc :
Power output is 16 bhp at 21,500 rpm. This means 320 bhp per liter and a Pme of nearly 16 kg/cm2 ! As regards bhp per litre, this is a figure that has never been surpassed by any naturally aspirated four stroke engine, and even today's formula 1 cars with their special fuel brews cannot hold a candle to it.
Power output is 16 bhp at 21,500 rpm. This means 320 bhp per liter and a Pme of nearly 16 kg/cm2 ! As regards bhp per litre, this is a figure that has never been surpassed by any naturally aspirated four stroke engine, and even today's formula 1 cars with their special fuel brews cannot hold a candle to it.