Small-Wheel Wonder: 1977-1982 Vespa P150X

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Vespa P150X
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Honda Elite 150
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Bajaj Chetak

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.

The PX also inherited the 10-inch diameter wheels of the sportier Vespa models, first introduced on the VS1 GS 150 of 1955 and adopted across “premium” 150 models from the VLA 150 GL of 1962. The larger wheels improved handling by increasing their gyroscopic effect. Unfortunately, the PX also inherited the VS1’s 6-inch SLS drum brakes, rather than the 7-inch drums from the VSB 160 GS.

The PX was also the first Vespa with electric start and a 12-volt electrical system. Electronic ignition arrived with the P150X-E of 1981. At the same time, locks for the side panels were moved beneath the seat to deter thieves. And the front suspension was modified to reduce the inherent trailing link “dive” under braking. In many ways, the P150X was the ultimate “real” Vespa, the culmination of 30 years of active development. The VLX line remained in production until 1999 after more than 345,000 were built!

If you’ve never ridden a classic Vespa, it’s truly a unique experience. The PX’s electric start is just a nicety; any Vespa in good condition will start on the first lazy kick. Rolling off the center stand, you feel the weight of the engine on the right side. But as soon as you pull in the clutch, twist the left grip back to select first gear, open the throttle, feed in the clutch and you’re rolling, the asymmetry evaporates. Handling is vague and twitchy, especially with the odd weight distribution, small wheels and open frame. Suspension is lively, and the brakes are sluggish. A Vespa may not be considered a “real” motorcycle by many motorcycle enthusiasts, but when you consider you’re riding a design icon and an expression of Italian moto-art as definitive as a Ducati 916, all other considerations disappear. And besides, they’re fun. Avanti! MC

Contenders: Scooter rivals to Vespa’s P150X

1985-1987 Honda Elite 150
10hp @ 7,500rpm (est.)/65mph
152.7cc liquid-cooled SOHC 4-stroke single
Centrifugal clutch, Honda V-Matic belt-drive CVT
Price then/now: $1,798 (1986)/$1,500-$3,000

Honda entered the 150cc scooter market for just four years, but produced three different versions. In 1984 the first Elite, the 125cc CH125, arrived as the “Deluxe” with a pop-up headlight and digital dash, followed by the similar but larger 150cc CH150 in 1985. A “standard” version featured an analog dash and integrated headlight. For 1987, the Deluxe was dropped and the standard model fitted with new, sleeker bodywork.

All were powered by a unique single overhead cam, liquid-cooled 4-stroke engine with an automatic transmission. Suspension used a trailing link at the front, while the transmission acted as a swinging arm at the rear, attached by dual spring/shock units. Wheels were 10-inch cast aluminum.

Considering the short production run, an impressive number of Elite 150s are still on the road, most owners reporting excellent durability and reliability — though an oil change every 1,000 miles is recommended. If you decide to buy one, check the centerstand (it’s weak and can fail), and look for cracks in the intake manifold (resulting in lean running). A dead starter may just be due to a failed rear brake interlock switch, a common fault. Otherwise, the Honda CH150 is twist and go!

1980-2009 Bajaj Chetak
7.7hp @ 5,000rpm/60mph
145.5cc rotary valve 2-stroke single
4-speed, direct final drive
Price then/now: $3,999 (2005)/$1,500-$2,500

Bajaj is the sixth-largest motorcycle manufacturer in the world, and at one time produced more than 100,000 Chetaks a month! Essentially a license-built 1965 Vespa VLB 150 Sprint, the Chetak remained in production long after its Italian counterpart, gaining a 4-stroke engine in 2002.

The first Chetak copied Vespa’s earlier generation 145cc fan-cooled, rotary-valve engine, with breaker points ignition, 6-volt electrics and a kickstarter only. While it was fitted with the larger 10-inch wheels, the drum brakes were just a weedy 5-inch diameter. A large glove box was fitted behind the leg shield, and turn signals were added around 1990, incorporated into a squared-off front housing.

The Chetak became both a treasured possession and a family workhorse in India, and as a result very few low-mileage examples survive there. Few were sold here in the U.S., and parts are hard to find. If you buy one, check mechanical operation carefully, and look for signs that your scooter may have been reconstructed from two halves welded together, apparently a common practice in India! Vespa also licensed another Indian company, LML, to produce the P150X, from 1986-on, and it’s still available in the U.S. (except California) as the 150 Stella, imported by Chicago’s Genuine Scooters.

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