Small-Wheel Wonder: 1977-1982 Vespa P150X

A Vespa P150X may not be considered a "real" motorcycle by many motorcycle enthusiasts, but they sure are fun.

  • Vespa P150X
    Image courtesy Piaggio
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Vespa P150X
Years produced:
1977-1982 (with variants to 1999)
8.8hp @ 5,700rpm
Top speed:
149.6cc (57.8mm x 57mm) fan cooled, rotary valve 2-stroke single
4-speed, direct final drive
Price then/now:
$1,250 (est.)/$1,500-$3,000

Care to guess how many Vespas were built at Piaggio’s Pontedera plant outside Pisa, Italy, over the 50 years between 1946 and 1996? More than 15 million! During that time, the Vespa was refined and improved with more power, better equipment and increased performance, but the fundamentals of Corradino D’Ascanio’s iconic design remained essentially the same.

Prior to World War II, Piaggio was known for airplane engines, and during the war manufactured strategic bombers. D’Ascanio had been a successful aeronautical engineer, and the Vespa bears witness to that. Even the 98cc 2-stroke engine used in the earliest Vespas originated as a starter unit for the 1,350hp Piaggio P.XII engines in the company’s P.108 heavy bomber. The trailing-link front suspension is also said to have been modeled on the P.108’s tail wheel!

In D’Ascanio’s Vespa, a stamped-steel monocoque chassis suspends both wheels from single-sided swingarms, the rear incorporating the engine/transmission unit so it moves with the rear wheel as unsprung weight. Coil springs and dampers control movement at both ends. The single-cylinder 2-stroke engine is force-air-cooled by a fan fixed to the crankshaft, which also drives the wet multiplate clutch and 3-speed (later 4-speed) gearbox, with the output shaft carrying the rear wheel. That basic specification covers all 2-stroke Vespas from 1946 to 2007 including the long-running P150X (Piaggio’s official model designation was VLX 150 PX) and its variants.

The P150X of 1977 evolved from the 1969-1979 145cc VLB 150 Sprint Veloce, but with a slight bore increase of 0.8mm for 57.8mm and 149.6cc. Power increased by 0.3hp to 8.8 at 5,700rpm. The engine breathed through a 20mm Dell’Orto carburetor and an innovative rotary valve system first introduced in 1958 on the VBA 150. The left-side crankshaft counterweight controlled the intake, which thus fed right into the crankcase, lubricating the connecting rod bearings directly. This allowed use of a 2-percent oil/fuel mix — better than the smoky 5 percent required by the previous piston-port engines.

True to its “large frame” Vespa lineage, the PX bodywork carried a glove box behind the front fairing and spare wheel stowage under the left side blister (from the VSB 160 GS MkII of 1963). It also used the 8-liter fuel tank from the P200X which, with its better fuel consumption, gave the P150X a range of around 170 miles.

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