Aprilia RS125 2006-2012 Service Manual

Aprilia introduced the RS125 in 1992 as a Grand Prix-derived sports replica. The 2006 model brought a redesign with an upside-down fork, a radial front brake and a new cast aluminum frame. This range is the final generation before the RS4 125 replaced it in 2012 and switched to a fuel-injected four-stroke.

Power comes from a 124.8cc liquid-cooled single-cylinder Rotax two-stroke, with a Nikasil-coated aluminum cylinder, reed-valve intake and separate oil injection. Bore and stroke are 54 x 54.5mm with a 12.5:1 compression ratio. Fuel comes from a Dell'Orto carburetor (PHBH 28 BD early on, VHST 28 on later bikes), with CDI ignition and electric start. The gearbox is a 6-speed with a multi-plate clutch in an oil bath, gear primary drive and chain final drive.

Claimed output is about 28 hp at 10,500-11,000 rpm and 19-20 Nm of torque on the 2006-2007 bikes. The 2008-2009 bikes are listed at 33 hp, and the full-power tune is around 34 hp at 11,000 rpm. Many bikes were restricted to 15 bhp for learner licences and could be unrestricted with a full-power kit. The 2012 model was homologated to Euro 3, while a 21 kW German-market version stayed on the PHBH 28 carburetor and Euro 2.

The chassis is a sloping twin-spar frame in thin-wall box-section cast aluminum with cross-rib reinforcement, with a 40mm upside-down fork and a hydraulic monoshock with adjustable spring preload. Brakes are a floating 320mm front disc with a radial 4-piston caliper and a 220mm rear disc with a 2-piston caliper. Confirmed figures list a 53-inch (1,346mm) wheelbase, a 31.7-inch (805mm) seat height, a 3.7-gallon (14-litre) tank, and 110/70 ZR17 front and 150/60 ZR17 rear tires. Special editions in the range include the 2006 Poggiali Replica and the 2006-2007 RS 125 Nero.

This factory service manual covers the procedures, torque specs, and diagrams needed to keep a 2006-2012 RS125 running the way it was built to.