The Aprilia RS4 125 (sold as the RS125 since 2016) is a 125 cc class sportbike manufactured by Italian motorcycle firm Aprilia. The four-stroke RS4 125 replaces the extremely popular RS125 two-stroke race replica in Aprilia’s lineup. 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.
