Vespa ET2 50 Make Model | Vespa ET2 50 | Year | 1996-00 | Engine | Two stroke, single cylinder | Capacity | 49.3 cc / 3.0 cub in | Bore x Stroke | 40 x 39.3 mm | Compression Ratio | 11:1 | Mixture | Automatic mixing | Carburetor | Weber / Dell'Orto / Mikuni 2-phase | Cooling | Air cooled, forced | Ignition | Electric | Starting | Kick start | Clutch | Automatic, dry centrifugal | Max Power | 3 kW / 5.1 hp @ 7500 rpm | Max Torque | 4.4 Nm / 0,45 kgf-m / 3.2 ft/lb @ 6500 rpm | Transmission | Centrifugal automatic gearbox | Final Drive | Belt | Frame | Loadbearing pressed sheet steel | Front Suspension | Hydraulic single shock | Rear Suspension | Hydraulic single shock | Front Brakes | 200 mm disc | Rear Brakes | 110 mm drum | Wheels | Pressed die cast aluminium alloy | Front Tyre | 100/80-10" | Rear Tyre | 120/70-10" | Dimensions | Length: 1760 mm / 69.3 in Width: 670 mm / 26.4 in | Wheelbase | 1280 mm / 50.4 in | Seat Height | 805 mm / 31.7 in | Wet Weight | 92 kg / 203 lbs | Fuel Capacity | 9 L / 2.4 US gal | Consumption average | 3.6 L/100 km / 28 km/l / 65 US mpg | Top Speed | 45 km/h / 28 mph | Colours | White, Pearl white, Seafoam green, Blue, Dragon red, Alabaster | Review | Motorcycle.com | With all due respect to the Vespa's 50th birthday and the important new ET4 125cc model, the understated 50cc ET2 is the one that really deserved the spotlight.
Simply put, the 50cc ET2 has the most sophisticated two-stroke engine ever mass-produced. Period. This little wonder is already able to pass the stringent European emission regulations coming in the year 2000 without a catalytic converter! GM, Ford, Toyota, Subaru and many others have been spending mega-bucks trying to develop clean two-stroke engines for their cars while Honda has been pursuing the same goal through the development of their experimental (and expensive) EXP-2. However, the EXP-2's technologically advanced engine and all of the auto engines are yet to reach production. It is an impressive coup indeed for a small factory like Piaggio to produce a clean two-stroke ahead of all others.
So why are all the factories interested in two-strokes? Loads of power, light weight, few moving parts and low bulk. But stand behind any idling old RD Yamaha and the two stroke engine's pitfalls become clear (or rather obscured in the smoke...) Massive amounts of pollution mean a death sentence for two-strokes in many countries. If it only could be made to burn cleaner we would have a powerful, light and inexpensive power unit. The main reason for the pollution created by a normal two-stroke engine is the "short circuiting" that occurs during the transfer process. Fuel-air mixture sucked into the combustion chamber rushes out the transfer ports and helps to drive the previous cycle's burnt gases from the cylinder. Although most of the fresh mixture remains inside, a small percentage sneaks out to the atmosphere through the wide-open exhaust port. Without any physical barrier between the fresh mixture and burnt gases this is unavoidable. That small percentage of unburned fuel multiplied by thousands of RPM gives the EPA and other green operations fits. It also hurts the engine's already poor mileage.
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