Aprilia has unveiled a completely revised RS4 at the EICMA Show in
Italy. It will be offered in two versions: Aprilia RS4 50 and Aprilia
RS4 125. The first version, the RS4 50, is powered by a single cylinder,
liquid cooled 50 cc 2-stroke engine while the second version, the RS4
125, is powered by a single cylinder liquid cooled 125 cc 4-stroke with
electronic injection, 4 valves, and double overhead camshafts (DOHC).