Lambretta Model Junior 50

J50 Specifications

Years: 1964 - 1966 (J50)
Amount produced: 69,988
Engine: 1 cylinder, air cooled 2-stroke
Induction: piston ported
Bore: 38 mm
Stroke: 44 mm
Cubic capacity: 49.8 cc
Compression ratio: 7.5:1
BHP at rpm: 1.47 @ 4500
Transmission: 3 speed constant mesh
Lubrication: 2%
Carburetor: Dellorto SHB 18/12
Ignition: contact breaker & points
Ignition timing: 21 degrees BTDC
Breaker gap: 0.35-0.45 mm
Voltage: 6 volt
Wheel size: 9"
Tire size: 2.75 x 9
Max speed: 25 mph
Total dry weight: 171 lbs

J50 Deluxe Specifications

Years: 1968 - 1970 (J50 Deluxe)
Amount produced: 28,852
Engine: 1 cylinder, air cooled 2-stroke
Induction: piston ported
Bore: 38 mm
Stroke: 44 mm
Cubic capacity: 49.8 cc
Compression ratio: 7.5:1
BHP at rpm: 1.48 @ 4500
Transmission: 3 speed constant mesh
Lubrication: 2%
Carburetor: Dellorto SHA 18/12
Ignition: contact breaker & points
Ignition timing: 21 degrees BTDC
Breaker gap: 0.35-0.45 mm
Voltage: 6 volt
Wheel size: 10"
Tire size: 3 x 10
Max speed: 25 mph
Total dry weight: 176 lbs

J50 Special Specifications

Years: 1970 - 1971 (J50 Special)
Amount produced: 13,599
Engine: 1 cylinder, air cooled 2-stroke
Induction: piston ported
Bore: 38 mm
Stroke: 44 mm
Cubic capacity: 49.8 cc
Compression ratio: 7.5:1
BHP at rpm: 1.48 @ 4500
Transmission: 3 speed constant mesh
Lubrication: 2%
Carburetor: Dellorto SHA 18/12
Ignition: contact breaker & points
Ignition timing: 21 degrees BTDC
Breaker gap: 0.35-0.45 mm
Voltage: 6 volt
Wheel size: 10"
Tire size: 3 x 10
Max speed: 25 mph
Total dry weight: 176 lbs

LAMBRETTA MODEL JUNIOR 50 HISTORY

Three years after its presentation at the Milan motor show in 1961, the 50cc prototype was completely redesigned and finally hit the market at the end of 1964, exactly one year after its competition, the Vespa 50. The new Lambretta 50 was christened the "Junior" in honor of its young clientele. Apart from a few modest changes to the bodywork, the mechanical system and the suspension of the 50 Junior was sensibly improved compared to the 1961 protype.

The specific changes to the motor were the switching of the rotating valves for a more traditional system and a completely overhauled gearbox with the introduction of a third speed. The front suspension was reinforced and became essentially the same as the Lambretta Cento, while an efficient hydraulic shock was added to the rear suspension. Even though the wheels were ten inches in diameter on the prototype, they were shrunk to only nine inches on the finally version.

As already seen on its big sister, the Cento, the frame of the J 50 soon revealed that it was far too fragile in the middle part, which caused customers to worry about the safety of the scooter.

To resolve this delicate problem, Innocenti totally redesigned the body and especially the structure. The rear section of the scooter was modified, and the front legshield was reduced. With these improvements, the Lambretta J 50 became the "Second Series" and was officially presented to the public on November 26th of 1966 at the Centro Studi in the Lambrate area of Milan. In spite of these noteworthy improvements, the selling price remained unchanged at 109,000 Italian lira, but the new version was offered in two different colors: "aquamarine blue" and white.

The two different versions of the Junior 50 were remarkably successful but were never able to compete with the market supremacy of Piaggio in the area of small engine scooters.

To increase the appeal of the J 50, a new version dubbed the De Luxe was released in 1968 that had a more refined streamlining. Polished aluminum pieces in the form of arrows were mounted on the side panels (similar to those on the LI Special) and the rear section had a "De Luxe" emblem. Besides that, the connectors for the side panels were substituted with a spring-loaded hook that connected to the internal border around the main frame. Other modifications were to the strips on the floorboards, the size of the wheels (from 2.75 x 9 to 3.00 x 10), and the shape of the seat.

With this new version, Innocenti returned to the old tradition of painting the hubs and rims of the scooter in aluminum, while a shining "field green" was added to the gamut of colors offered. The last version of the Junior 50 appeared in the spring of 1970 alongside, but not replacing, the preceding model. With the nickname of "Special", this Lambretta would be the last 50cc model built by the Innocenti factory before the assembly line was transferred to the Indian government. The new model had many new esthetic modifications. The covering for the floorboards was now a black rubber mat; the seat was now two tone and more slender; the arrow metal pieces on the side panels were modified; and a more practical handle was added, which helped to maneuver the scooter from when it was stopped.

Innocenti completely changed the list of colors available, which were definitely aimed at a younger clientele: red. Turquoise, and "ochre yellow".

Unfortunately, the Special was never quite able to find its market niche, and less than 14,000 units were ever produced before production was halted in April 1971.

You can find the parts catalog by clicking the link below.

INNOCENTI SPARE PARTS CATALOGS for Junior models.