Honda RC166 race bike from the 1960s had a 250cc inline-six engine with 65-hp and the ability to rev to nearly 20,000 rpm! It was a great achievement. Moreover, it was fast enough to have propelled Mike Hailwood to 2 world championships, and it sounds amazing, too.
The RC166 can do some incredible things, as you'll see in this 2012 video recorded in Japan. Please amp up the volume on your computer or mobile device. This is something you cannot afford to miss.