Aprilia RX/SX 50

The 2006 Aprilia RX/SX 50 is a street/off-road motorcycle widely produced by Aprilia. It is powered by a six-speed, carburetor-fuelled, nikasil-lined and cast iron single-cylinder two-stroke engine manufactured by Derbi/Piaggio.

Aprilia RX/SX 50

2008 Aprilia SX50
Manufacturer	Aprilia
Parent company	Piaggio
Production	2006-present
Class	Motocross, Supermoto
Engine	49.76 cc, 11.5:1 CR, liquid-cooled, carburetor-fuelled two-stroke
Power	+/- 6.5 hp (4.8 kW) Restricted, 12 hp (8.9 kW) Derestricted
Transmission	6-speed manual
Suspension	Ø40 mm hydraulic fork with leading axle; wheel travel 195 mm Rear: hydraulic monoshock; Non-adjustable; wheel travel 180 mm
Brakes	Front: 300 mm stainless steel disc; floating quad-piston caliper Rear: 180 mm stainless steel disc; twin-piston caliper
Fuel capacity	7 litres
Related	Aprilia RX50, Aprilia MX50, Aprilia SX125

Styling and concept

The 2006 Aprilia RX/SX 50s are the renovated successors of the Aprilia RX 50 first produced in 1992; the panels and layout are based closely on the bigger displacement Aprilia RXV/SXVs.

Engine

The engine in the Aprilia SX 50 is sourced from Derbi/Piaggio (D50B0/D50B1). This engine is used in the Derbi Senda DRD/X-Race/X-Treme supermotos and crossers, as well as the 2006 onwards Derbi GPR 50 and Aprilia RS 50 road bikes, although the road bikes feature an electric starter instead of a kickstarter on the supermotos. Engine parts from the crossers and supermotos can be directly swapped with one another; there are some small differences between the road bike and supermoto engine and frame which may require modification to transfer some external engine parts (exhaust, airbox etc.)

Specifications

SX50

50 cc single cylinder, six-petal reed valve case induction and two-stroke injection (automix) carburetor fueled.

Engine displacement – 49.76 cc

Bore/stroke – 39,88×40 mm

Compression ratio – 11.5:1

Clutch – Wet, multiple plate

Starting – Kickstart

Exhaust = Catalytic converter

Rotor Ignition/Generator = 85w/120w

Cooling system – Liquid-cooled

Fuel tank size = 7 litres

Fuel system – Carburetor Dell'Orto PVHA 17.5 mm

Main jet = 95

Needle Jet = A13, notch #2

Idle jet = 30

Transmission

1st = 1st 11/34

2nd = 2nd 15/30

3rd = 3rd 18/27

4th = 4th 20/24

5th = 5th 22/23

6th = 6th 23/22

Primary drive = 21/78

Sprockets

Front = 11 Teeth

Rear = 53 Teeth

Overall Final Drive ratio = 11/53

Spark plug = DENSO W27ESR-U/IW27 NGK BR9ES/BR9EG/BR9EIX

Gap = .6-7 mm

Wheelbase = 55.354 in (1,406 mm)

Length = 79.68 in (2,024 mm)

Width = 80.511 in (2,045 mm)

Height = 32.677 in (830 mm)

Tires = Front: 100/80 - 17 inch; Rear: 130/70 - 17-inch

RX50

50 cc single cylinder, six petal reed valve case induction and two-stroke injection (automix) carburetor fueled

Engine displacement = 49.76 cc

Bore/stroke = 39,88×40 mm

Compression ratio = 11.5:1

Clutch = Wet, multiple plate

Starting = Kickstart

Exhaust = Catalytic converter

Rotor Ignition/Generator = 85w/120w

Cooling System = Liquid-cooled

Fuel Tank Size = 7 litres

Fuel System = Carburetor Dell'Orto PVHA 17.5 mm

Main Jet = 95

Needle Jet = A13, notch #2

Idle Jet = 30

Transmission

1st = 1st 11/34

2nd = 2nd 15/30

3rd = 3rd 18/27

4th = 4th 20/24

5th = 5th 22/23

6th = 6th 23/22

Primary Drive = 21/78

Sprockets

Front = 14 Teeth

Rear = 53 Teeth

Overall Final Drive ratio = 14/53

Spark Plug = DENSO W27ESR-U/IW27 NGK BR9ES/BR9EG/BR9EIX

Gap = .6-7 mm

Wheelbase = 55.354 in (1,406 mm)

Length = 79.68 in (2,024 mm)

Width = 80.511 in (2,045 mm)

Height = 32.677 in (830 mm)

Tires = Front: 90/90 - 21 inch; Rear: 110/80 - 18-inch

Restriction

Restriction varies depending on the country and sky, person, or company the bike is purchased from. The engine is usually restricted in the following ways:

Carburetor

'Strangle' baffle/plate in Air filter manifold

74 Main jet

Exhaust

Exhaust fume/pressure outlet pipes

Catalytic converter

Sprockets

Front; reduced to 11/53 or 12/53

Ignition system (only on models 2018 and after)

Limited to 8000 RPM

References

• "SX 50 Technical sheet". Aprilia. Archived from the original on 3 May 2014. Retrieved 18 September 2018.
• Biker, Maxx (17 July 2009). "2009 Aprilia RX50/SX 50". Top Speed. Retrieved 18 September 2018.