Journal: Moto Guzzi’s Otto Cilindri Packed a Big Block Into a Coffee Can

Moto Guzzi’s Otto Cilindri Packed a Big Block Into a Coffee Can

By Alan Franklin
July 16, 2013

I hold both V8s and complex engineering in miniature in pretty high regards. On the surface, while these two things may not seem to be all that compatible (with V8s stereotypically being large, lazy things with equally large and lazy build tolerances and have the kind of motor whose displacement is measured in cubic inches or liters and not cubic centimeters), this clearly isn’t always the case. Ferrari, for example, has been building some of the greatest V8s to ever burn fuel for generations now, and they’ve all been relatively small, techy motors with high rev limits and specific power outputs—even these, however, seem massive and slow-witted when compared to my all-time favorite V8, the Moto Guzzi GP bike of the mid-1950s, an epic mix of the two seemingly wildly disparate design characteristics.

Following on the heels of fellow Italian Plinio Galbusera, who built a prototype two stroke V8 as early as 1938, Guzzi engineers set about building a new four-stroker of identical 500 cc displacement—an infinitely more difficult proposition given the advanced spec chosen for competiveness in high-level racing. Built of magnesium and featuring two overhead cams per bank and eight individual 20 mm carburetors, the resultant engine whirred out 78 HP at 12,000 revs and contributed a shade under 100 pounds to the overall bike’s total of 330. I’ll spare you a few adjectives and simply describe it’s sound as sublime.

First raced in 1955, it proved ferociously fast but temperamental, too. Despite an easy 10-horsepower advantage and a 178 MPH top speed that would remain unbeaten for two decades, the mighty Otto Cilindri won few races. In addition to its fragility, the bike suffered bad handling and roadholding, its primitive chassis technology somewhat behind the thoroughly futuristic drivetrain contained within it.

Though substantially redesigned for improved reliability in 1957, it was a case of too little, too late. The bike still handled and braked poorly, and near the end of its career, team riders refused to race it for fear of their lives (this from men not afflicted with a normal, healthy sense of mortality). Later that year Guzzi completely withdrew from GP racing, robbing history of one of the most promising and exciting two-wheelers of the era, if not ever. With continued refinement it’s exciting to dream about what could have been—though deeply flawed, the Otto clearly showed truckloads of undeveloped potential.

Looking back on this incredible chapter of motorcycle history, I’m just glad someone actually had the guts to build such an audacious machine—the kind of thing that surfaces from time-to-time as a long-forgotten, far-fetched blueprint from the drafting desk of an engineer suffering fever dreams, but that rarely ever made it to physical reality. Of course it’d be wonderful if Guzzi had figured out how to make the reluctant beast turn and stop, but at least we have YouTube videos of it running in anger. Now if you’ll excuse me, I have to go connect my laptop to my stereo.


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Stephan Protzen
Stephan Protzen
10 years ago

More information on this jewel can be found in “Classic Italian racing motorcycles”, Mick Walker and “Classic motorcycle race engines”, Kevin Cameron. The later is a must read for anyone with an interest in the development of the racing engine.

Eddie Relvas
Eddie Relvas
10 years ago

I first found out about this motorbike decades ago, and I was fascinated by it, but couldn’t find much more info on it. Thanks for a very interesting piece of history (and the video… the sound is indeed quite something!).

Definitely not the prettiest bike in the world, but surely one of the most fascinating.

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