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Moto Rumi – The Two Shooter Scooter

When you’re a freelance writer, rule one is—the editor is always right. And if he’s wrong, he (or she) is still the editor, with the power to run or “spike” your story. As Editor Campbell described in CB332 (July), until his road to Damascus epiphany in Victoria, scooters were always verboten in these pages. I’m not planning to open the floodgates on small-wheel cycles in the light of this editorial volte-face, but I may sneak one or two in every so often…enter the Moto Rumi.

Moto Rumi

Donnino Rumi was born in 1906 in the northern Italian town of Bergamo. The Rumi family owned and operated a brass foundry in the early 20th century, which grew into a diversified manufacturing company employing more than 100 people by 1939. During WWII, the Rumi works were appropriated by the occupying forces and turned to munitions production. Donnino went into hiding rather than bend to his German overseers, but was captured in 1943 and interned for the duration of the War.

After the liberation, Donnino Rumi found himself in sole charge of the family business, which had grown to around 600 workers. With a large factory and foundry, the company needed to get back into production: and like many other Italian manufacturers at the time, they turned to making small, economical motorcycles. The engine Rumi chose was designed by Pietro Vassena, who had developed a two-stroke twin-cylinder engine intended to power a microcar. Rumi designed a complete motorcycle around Vassena’s engine, and a prototype was shown at the Milan show in 1949. 

The Moto Rumi Tourismo went into production in 1950 and was continually developed over the 1950s with revisions to suspension and frame design, and increases in power.

Vassena’s engine was an air-cooled two stroke parallel twin of 125cc using deflector pistons to scavenge the combustion chambers rather than the Schnuerle loop-scavenge system then becoming popular. 

Cylinders were cast iron with alloy heads. The three-main-bearing crankshaft ran in horizontally-split engine cases with the three-speed gearbox in unit, driven by gears from an engine-speed clutch. In stock form the engine made around 6.5 hp.

Noting the rapid growth of the scooter industry, Rumi’s next two designs were the Scoiattolo (squirrel), essentially a motorcycle with a pressed-steel monocoque frame and full weather protection; and what many consider to be Donnino’s masterpiece, the Formichino (Little Ant). He used his skills as an accomplished artist and sculptor to create a unique and stylish design.

The Formichino used Vassena’s engine as a stressed frame member, bolted to two aluminum castings (from Rumi’s own foundry). These formed the front frame section containing the headlight, gas tank and steering head; and the rear frame/rear wheel enclosure. Drive to the rear wheel was by a fully enclosed chain, the casing of which was also cast in aluminum and formed the rear suspension’s single-sided swingarm. Aluminum was also used for the front fender and even the muffler!

The powertrain now contained four gears, and, fed by a single 18mm Dell’Orto carburetor, the Formichino produced 6.5hp, giving it a top speed of around 85 kmh. For 1958, a more powerful version (the Tipo Sport) was announced, with revised cylinder heads and a single 22mm carburetor for eight hp and a top speed of around 105 kmh. It featured 10-inch wheels instead of the eight-inch items fitted to the base model Formichino. 

Along the way, the iron cylinders were replaced by chrome-plated alloy barrels, and the TS was also sometimes fitted with a dualseat replacing the separate saddles.

In the mid-1950s, scooter racing was becoming increasingly popular. Rumi had experienced much track success with their 125cc motorcycles, so they entered two modified Formichinos in the 1956 Bol d’Or 24-hour race at Montlhery in France, winning the scooter class. They repeated their success in 1957 and again in 1958, with the winning Formichino averaging over 87 kmh. To commemorate this success, a Bol d’Or replica was sold in 1960, painted gold and fitted with dual carbs, for 8.5 hp.

But, like many Italian bikemakers, Rumi’s sales had  slumped by 1960. The Fiat Cinquecento car cost little more than a motorcycle and offered four seats. Donnino Rumi closed his company in 1962.

1961 Formichino Tipo Sport

Formichinos sold well in France and Britain, and were also manufactured under licence in Argentina and Belgium. The Formichino TS shown here is from 1961 but has an earlier engine modified to TS specification. UK Rumi guru Peter Caisley bored the iron cylinders for extra capacity (the chrome-plated originals are notoriously fragile) and also modified the undercut on the gearbox dogs to improve shifting, a known Rumi weakness. It also has modern electronic ignition, which improves starting.

I bought a Moto Rumi TS in 1966. It was my first motorcycle, and nearly put me off for life. It was almost impossible to start, and only ran on one cylinder until warm. As an ignorant 16-year-old, I decided the problem must be inside the engine, so I pulled off the cylinder heads. As often happened to the alloy cylinders, a broken piston ring had chewed up the bore around the exhaust port. With no skill and even less money for repairs, I had no chance of fixing it. I bolted the heads back on, and listed it in the classifieds.

Of course, now I wish I’d kept it; but that’s true of almost every motorcycle I’ve owned…

by Robert Smith Canadian Biker Issue #334

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