DITECH two-stroke engine

The SR50 DITECH uses the Synerject gasoline direct injection (GDI) system developed jointly by the Orbital Corporation andSiemens AG.

The system uses a cam-driven air compressor to deliver air to the cylinder head at a pressure of 5 bars (500 kPa; 73 psi), thereby avoiding the use of carburation; the cylinder walls are not wet with gasoline, only with lubricating oil. After the port is closed and the air is compressed by the piston, gasoline is injected by an atomizer like a spray nozzle mixed with and propelled by the highly compressed air, into the main combustion chamber where, after the injection port closes, and the piston is still rising, it is ignited in the compressed main charge of air

. The use of direct injection and stratified charge allows the DITECH engine to meet Euro 2 standards.^[1] A blower adds air to the exhaust to

reduce emissions from unburned fuel there.

Aprilia RS4

What mean Aprilia RS4 

The Aprilia RS4 125 is a 125cc class sportbike manufactured by Italian motorcycle firm Aprilia. The RS4 125 is a four-stroke variant of the extremely popular RS125 two-stroke race replica. It is marketed as a tamer, more practical option to the more aggressive, track-oriented RS125. The bike is based on the four-stroke version of the Derbi GPR125. A race kit is available from the manufacturer that boosts power from the standard 15 bhp to 25 bhp.

The RS4 125 is available with a quick-shift system similar to the RSV4, in which the engine halts the torque from the engine based on engine rpm, the amount of throttle being applied, and the speed of the bike. This system allows smooth, fast upshifts without the use of the clutch. The chassis is very high-spec, with an aluminium perimeter frame and aluminium swingarm. The brakes are also high-spec, with a 30 cm steel disc in front with a four-piston radial caliper and a 22 cm steel disc with a single caliper at the rear.