The Aprilia RS4 125 (sold as the RS125 since 2016)[1] 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.[5]

Aprilia RS4 125
ManufacturerAprilia
Also calledAprilia RS125 (2016–present)[1]
Parent companyPiaggio
Productionsince 2011
PredecessorAprilia RS125
Classsport bike
Engine124.2 cc (8 cu in) Single-Cylinder DOHC[2] four valve four-stroke
Electronic injection
Bore / stroke58.0 by 47.0 millimetres (2.28 in × 1.85 in)
Compression ratio12.5 ± 0.5:1
Transmission6 speed, multi-disk oil bath clutch
Frame typePerimeter frame, Die-cast Aluminium spars w/ crossed reinforcement ribs
Asymmetric aluminium swingarm
SuspensionFront: 40 mm inverted forks
Rear: Progressive monoshock
BrakesFront: Single 300 mm diameter stainless steel disc, radial 4-piston caliper w/ Bosch Single Channel ABS[3]
Rear: 218 mm diameter stainless steel disc, single 30 mm piston caliper
TiresFront: 100/80 - 17",
Rear: 130/70 - 17"
Wheelbase1353 mm
DimensionsL: 1968 mm
W: 760 mm
H: 1135 mm
Seat height820 mm (32 in)
Weight129 kg[4] (dry)
144 kg (wet)
Fuel capacity14.5 L (3.2 imp gal; 3.8 US gal)
Reserve: 3.5 L (0.77 imp gal; 0.92 US gal)
Fuel consumption2.71 L/100km
RelatedAprilia RS125, Aprilia RS4 50

Specifications

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The powerplant is an electronically fuel-injected 4 stroke 4 valve DOHC single cylinder, with a balance shaft.[6] A race kit is available from the manufacturer that boosts power from the standard 15 bhp to 25 bhp.[5]

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.[5] This is optional on the standard bike, but included with the GP Replica model.

The chassis is an aluminium perimeter frame with an aluminium swingarm. The brakes consist of 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. Complementing this for 2017 is Bosch 9.1ML single channel ABS, at the front.[3]

For 2021, the RS125 has undergone significant changes: some restyling at the front, fully digital instruments, a wider 140-section rear tyre, Full-LED headlights, Euro 5 emission compliance and dual-channel ABS.[7][8] The engine has also been modified: there is a new head, redesigned combustion chamber, new intake and exhaust ducts, redesigned camshafts and an iridium spark plug. The air intake and filter have been altered and the throttle body has been repositioned. There is a new exhaust system and catalyst, resulting in higher efficiency.[9]

Notes and references

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  1. ^ a b "Intermot 2016: Aprilia launches Tuono 125 and RS125". Overdrive.
  2. ^ "RS4 125 - Aprilia". Aprilia. Archived from the original on 20 June 2016. Retrieved 18 September 2018.
  3. ^ a b "Aprilia RS125 Technical Specification" (PDF). Aprilia. Retrieved 18 September 2018.
  4. ^ "RS 125 GP Replica - Technical Specifications" (PDF). wlassets.aprilia.com. Retrieved 30 Oct 2020.
  5. ^ a b c Ash, Kevin (20 June 2011). "Aprilia RS4 125 review" – via www.telegraph.co.uk.
  6. ^ "APRILIA RS125 (2017-on) Review".
  7. ^ "2021 Aprilia RS 125 And Tuono 125 Unveiled In Italy". www.motoroids.com. 28 April 2021.
  8. ^ "2021 Aprilia RS125 And Tuono 125 Unveiled In Italy". BikeDekho.
  9. ^ "New Aprilia RS125 and Tuono 125 unveiled". www.motorcyclenews.com.