2021 Aprilia RS 660 vs 2020 KTM 790 Duke

Full specifications comparison • 2 motorcycles

Comparing 2 motorcycles
2021 Aprilia RS 660 2021 Aprilia RS 660

Sport

Engine
Four stroke, forward facing parallel twin, DOHC with silent chain drive on the right side, four valves per cylinder
Power
100 hp / 73.5 kW @ 10,500 rpm
Top Speed
N/A
Weight
183 kg / 403.4 lbs
2020 KTM 790 Duke 2020 KTM 790 Duke

Sport

Engine
Four stroke, parallel twin cylinder, DOHC, 4 valve per cylinder
Power
78 kW / 105 hp @ 9000 rpm
Top Speed
N/A
Weight
169 kg / 372.5 lbs
Full Specifications
General
Year20212020
Make ModelAprilia RS 660KTM 790 Duke
Dimensions
Seat Height815 mm / 32.0 in825 mm / 32.4 in
Wheelbase1370 mm / 53.9 in1475 ± 15 mm / 58 in
Ground Clearance-186 mm / 7.3 in
Height-1059 mm / 41.7 in
Length-2062 mm / 81.2 in
Width-904 mm / 35.6 in
Weights & Capacities
Dry Weight169 kg / 372.5 lbs169 kg / 372.5 lbs
Fuel Capacity15 Litres / 3.9 US gal14 Litres / 3.7 US gal
Wet Weight183 kg / 403.4 lbs-
Performance
Max Power100 hp / 73.5 kW @ 10,500 rpm78 kW / 105 hp @ 9000 rpm
Max Torque67.0 Nm / 6.83 kgm @ 8,500 rpm87 Nm / 63.4 lb-ft @ 8,000 rpm
Engine
Displacement659 cc / 40.2 cu-in799 cc / 48.7 cu-in
Engine DetailFour stroke, forward facing parallel twin, DOHC with silent chain drive on the right side, four valves per cylinderFour stroke, parallel twin cylinder, DOHC, 4 valve per cylinder
Bore x Stroke81 x 63.93 mm88 mm x 65.7 mm
Compression Ratio13.5: 112.7:1
Cooling SystemLiquid cooled with radiator and water-oil heat exchangerLiquid cooled
EmissionsEuro 5 CO2 emissions - 116 g /km-
ExhaustAkrapovič - for race use onlyStainless steel primary and secondary silencer
Fuel InductionAirbox with front air intake. 2 ∅48 mm throttle bodies, Ride-By-Wire managementDell'Orto fuel-Injection
Ignition-Bosch EMS with RBW
LubricationWet sumpForced oil lubrication with 2 oil pumps
StarterElectricElectric
Drivetrain
ClutchWet, multi-plate, slipperPASC antihopping clutch, mechanically operated
Final DriveChain, with drive ratio: 17/43Chain 520 X-Ring
Primary Drive-39:75
Secondary Drive Ratio-16:41
Transmission / Drive6 Speed, AQS Aprilia Quick Shift6 Speed
Chassis
Frame TypeDouble beam aluminium frame with detachable rear seatChromium-Molybdenum-Steel frame using the engine as stressed element, powder coated
Suspension - FrontKayaba upside down fork ∅ 41 mm with counter spring, aluminium feet for fixing radial calipers. Adjustable for rebound, compression and spring preload.43mm WP upside-down
Suspension - RearAluminium swingarm with asymmetrical trusses. Monoshock with adjustable counter spring: rebound and spring preload.WP shock absorber with preload adjuster
Rake24.1°24°
Steering Head Angle-66°
Trail104.6 mm98 mm / 3.8 in
Wheel Travel - Front120 mm / 4.7 in140 mm / 5.5 in
Wheel Travel - Rear130 mm / 5.1 in150 mm / 5.9 in
Electronics
Electronics Package6-axis inertial platform, APRC suite which includes ATC (traction control, AWC (wheelie control), AEB (engine brake), AEM (engine map), ACC (cruise control) 5 Riding modes - (Road and Track, 3 fixed and 2 customizable)-
Wheels & Brakes
Brakes - Front2x 320mm Brembo radial calipers with 4 32mm opposing pistons. Radial pump and metal braided brake hose2x 300mm discs
Brakes - RearSingle 220mm disc; Brembo calliper with 2 isolated ∅ 34mm pistons. Pump with integrated tank and metal braided hosSingle 240mm disc
ABSABS Cornering multimapBosch 9MP two-channel ABS (incl. Supermoto mode, diesengageable)
Tyres - Front120/70 ZR 17 Tubeless radials120/70-17
Tyres - Rear180/55 ZR 17 (alternatively 180/60 ZR17) Tubeless radials180/55-17
Wheels-Cast aluminium
Wheels - FrontIn aluminium alloy 3.5 x173.50 x 17 in
Wheels - RearIn aluminium alloy 5.5 x175.50 x 17 in

Verdict

Winner on specs

2020 KTM 790 Duke

The 2020 KTM 790 Duke edges out the 2021 Aprilia RS 660 thanks to its lighter kerb weight, fuel injection, higher rear wheel travel, higher front wheel travel and larger displacement. Specifications are one part of the picture - dealer support, parts availability, and intended use all matter too.

Key Differences

2021 Aprilia RS 660 - Advantages

  • More power: Produces 100 hp vs 78 kW - a meaningful performance advantage.

2020 KTM 790 Duke - Advantages

  • Lighter: 169 kg vs 183 kg - easier to handle and less fatiguing on long trips.
  • Fuel injection: Precise fuelling, better cold-start reliability, and lower maintenance requirements.
  • Larger displacement: 799 cc vs 659 cc - more cubic capacity means broader torque delivery and greater low-end pull.
  • More rear wheel travel: 150 mm vs 130 mm - absorbs bigger hits and rough terrain better.
  • More front wheel travel: 140 mm vs 120 mm - greater compliance over rough surfaces.

2021 Aprilia RS 660 vs 2020 KTM 790 Duke - FAQs

What are the engine differences between the 2021 Aprilia RS 660 and 2020 KTM 790 Duke?
The 2021 Aprilia RS 660 uses Four stroke, forward facing parallel twin, DOHC with silent chain drive on the right side, four valves per cylinder, while the 2020 KTM 790 Duke is powered by Four stroke, parallel twin cylinder, DOHC, 4 valve per cylinder.
Which is lighter, the 2021 Aprilia RS 660 or the 2020 KTM 790 Duke?
The 2020 KTM 790 Duke is lighter at 169 kg compared to 183 kg for the 2021 Aprilia RS 660 - a difference of 14 kg. This is a meaningful difference that affects handling and rider fatigue.
Which has more power, the 2021 Aprilia RS 660 or the 2020 KTM 790 Duke?
The 2021 Aprilia RS 660 produces more peak power at 100 hp, compared to 78 kW for the 2020 KTM 790 Duke.
Which should I buy, the 2021 Aprilia RS 660 or the 2020 KTM 790 Duke?
Both are strong choices. The 2021 Aprilia RS 660 has the edge in more peak power, while the 2020 KTM 790 Duke stands out for lighter kerb weight and fuel injection. Visit dealers, arrange test rides, and factor in local parts and service costs - these often matter as much as the spec sheet.