1966 Honda RC166: The First Alien

Cycle News Staff | September 18, 2016

Article courtesy of Honda Financial Services. Learn how to finance your next Honda powersports product HERE.

If aliens from another galaxy had landed a flying saucer in the 1965 Monza Grand Prix paddock, it’s debatable whether their ride would have generated more attention than the six-cylinder 250cc racing machine Honda rolled out of the garage. When it was fired up, the RC165 unleashed an otherworldly scream the likes of which had never been heard anywhere. It was, literally, an ear-rattling announcement that a new world order had arrived in GP racing.

The RC165 was a technological sucker punch executed to perfection; the other guys never saw it coming. With the 1965 season almost at an end, the Honda crew flew with the bike in pieces to the penultimate Monza round so that it could be kept secret. The Monza test was a success.

For the 1966 GP season, Honda unveiled an updated 250cc six-cylinder, the RC166. The bike raised the bar so high, the outcome seemed inevitable before a single lap had turned.

For good reason: The RC166 was the precursor to Honda’s radical six-cylinder CBX street bike. Look closely at the RC166, and you’ll see staggering attention to detail. Six cylinders were crafted into a package no wider than a four-pot engine of the time, with each bore diameter about the width of two fingers. Dual overhead cams actuated 24 tiny valves, and the short-stroke, oversquare engine revved to a dizzying 18,000 rpm where it made 60 screaming horsepower and hit speeds upward of 149 mph. With its cylinder bank tipped forward and cast as an integral part of the top crankcase, the engine was decades ahead of any other machine, and it pioneered technology we would see from Honda for many years to come.

The RC166 destroyed the 250 class in 1966, amassing 10 victories in an incredible display of dominance, and captured the GP world championship again in 1967. With the departure of Honda from the Grand Prix scene in 1968, the chapter closed on one of the most amazing GP racing machines ever created.