Vespa 150 GS (1955-61)

The Vespa 150 GS, produced between 1955 and 1961, had 126,349 units made. It was equipped with a single cylinder, two-stroke engine that had a capacity of 145.5cc and a compression ratio of 7:1. The carburettor used was a Dell’Orto UB 23 S3, and it was air-cooled with a centrifugal fan. Ignition was from a 6 pole flywheel magneto, and starting was via a kick start. The clutch was wet, multiplate with cork inserts, and the max power was 6.0kW/8.2hp at 7500rpm. It was a 4-speed transmission with grip-shift, constant mesh, and direct drive for the final drive.

The frame was made of pressed sheet steel, with a streamlined monocoque structure. The front suspension was a stub axle with swinging hub and variable rate coil spring and double action hydraulic damper. The rear suspension was a swinging bracket for the engine and wheel, with variable rate coil spring and co-axial double action hydraulic damper. The front and rear brakes were both drum, expanding type with cooling ribs. The wheels were interchangeable, and the tyres were 3.5 x 10″.

The dimensions of the Vespa 150 GS were 1700mm x 700mm x 1050mm (length x width x height), with a wheelbase of 1180mm and a ground clearance of 285mm. The turning radius was 1400mm, and the dry weight was 100kg. The fuel capacity was 12L with a reserve of 1.2L, and the average consumption was 3.1L/100km, 32km/l, or 80 US mpg. The top speed was around 100km/h or 62mph. It was available in metallic blue/green.

Technical specifications:

Make Model: Vespa 150 GS

Year: 1955 – 61
Production: 126 349 units
Engine: Two stroke, single cylinder
Capacity: 145.5 cc / 8.8 cub in
Bore x Stroke: 57 x 57 mm
Compression: 7:1
Carburetor: Dell’Orto UB 23 S3
Cooling: Air cooled, centrifugal fan
Fuel Mixture: 1:15
Ignition: 6 pole flywheel magneto
Starting: Kick start
Battery: 6V
Clutch: Wet, multiplate with cork inserts
Max Power: 6.0 kW / 8.2 hp @ 7500 rpm
Transmission: 4 Speed, grip-shift, constant mesh
Final Drive: Direct drive
Frame: Pressed sheet steel, streamlined monocoque structure
Front Suspension: Stub axle with swining hub and variable rate coil spring and double action hydraulic damper
Rear Suspension: Swinging bracket for engine and wheel, with variable rate coil spring and co-axial double action hydraulic damper
Front Brakes: Drum, expanding type with cooling ribs
Rear Brakes: Drum, expanding type with cooling ribs
Wheels: Interchangeable
Front Tyre: 3.5 x 10″
Rear Tyre: 3.5 x 10″
Dimensions: Length: 1700 mm / 67 in Width: 700 mm / 27 in Height: 1050 mm / 41 in
Wheelbase: 1180 mm / 46.4 in
Ground clearance: 285 mm / 11.2 in
Turning Radius: 1400 mm / 55 in
Dry Weight: 100 kg / 220 lbs
Fuel Capacity: 12 L / 3.17 US gal
Reserve: 1.2 L / 0.3 US gal
Consumption average: 3.1 L/100 km / 32 km/l / 80 US mpg
Top Speed: 100 km/h / 62 mph
Colours: Metallic blue/green
Sources: Scooterlounge.com