Jesus Christ. Turn your speakers down, because this is just incredible. I wasn’t paying attention the first time I watched this – you hear a tiny idle and I naively thought it was the motorcycle. Then you see that the noise was just a generator for a wheel to bump start the racer. 5 cylinders, each 25cc, could rev up to 21,500 rpm:
To be frank, this video is taken so close that there isn’t really a great sound, it’s just sheer volume. Unfortunately, there really aren’t many other videos of the RC148 for you to get an idea of what this must have sounded like at full chat. Here’s the best I could find:
If you want to learn more about the RC148, check out wonderful profile on the bike and Luigi Taveri, the man who had to tame the beast, from MotorcycleUSA. A choice quote from the article, from Taveri:
“…below 16,000 rpm there was a good chance it would stop running all together.”