2021 Aprilia SX 125 and RX 125 First Look (13 Fast Facts)

March 9, 2021

Kids and beginners in Europe get all the fun—witness the 2021 Aprilia SX 125 and RX 125. The SX is a wheelie-ready supermoto motorcycle, with the RX 125 looks ready for serious off-road fun. Euro 5 is the big news this year, and these Aprilia 125s have a new engine as a result. Let’s take a closer look at this pair of eighth-liter tiddlers.

1. The two motorcycles are pretty much the same, except for the wheels and tires. The SX gets a pair of 17-inch hoops, while the RX goes with the off-road traditional 18-/21-inch set. Although both bikes use CST tires, the SX gets the pure-street Magsport rubber, while the SX gets dirt-ready knobbies.

2. Aprilia redesigned the 124cc top-end in several ways. However, the bottom end has been left alone.

3. The intake path is redesigned. There is a new air filter, new cylinder head, and the throttle body sits higher for a more direct shot into the new combustion chamber. A Marelli MIUG4 ECU keeps track of the fueling and 32mm throttle body.

4. New valve springs and bucket tappets are more precise, as is the new camshaft.

5. An iridium spark plug gets the fires burning.

6. The new exhaust system has a new catalyst, and the muffler is steel.

7. Aprilia tuned the 2021 SX 125 and RX 125 motors for more low-rpm torque. While Euro licensing rules limit the engine to 14.75 horsepower, nothing stops the production of more acceleration-oriented torque. Sure, 8000 rpm sounds like a high rev-count for the maximum torque, but these are road-going 125s, so engine speed is critical to performance.

8. Estimated fuel consumption is low at 90 mpg. If the Aprilia 125s get ridden like supermoto and off-road machines, that number will probably go down.

9. The SX has a 300mm front disc for maximum performance on pavement, while the RX has a dirt-friendly 260mm front disc. Both are actuated on by a floating dual-piston caliper.

10. Bosch ABS is standard on both models. In addition to preventing skidding, the Bosch system also mitigates rear wheel lift. Yes, we know—that doesn’t sound like much fun on a supermoto or dual-sport motorcycle.

11. Considering they will appeal to novices, the two Aprilia 125s have tall seat heights. The SX’s seat is 34.6 inches above the pavement, and the RX’s saddle is another inch higher. The curb weight of under 300 pounds for both models helps make the Aprilia 125s more manageable.

12. The orange-background LCD dash is updated. Aprilia says the electronic dash has something called a “travel diary.” We’re not sure what that is, however. It also keeps track of your top speed, and there are two tripmeters.

13. Although we don’t have prices or arrival dates in European dealers, we do know what colors will be available. The dual-sport RX 125 is available in a new Rally Tribute colorway, along with Silver Speedway. If you want the SX 125, you will have to be content with Red Raceway.

2021 Aprilia SX 125 (and RX 125) Specs

ENGINE

Type: Single cylinder
Displacement: 124cc
Bore x stroke: 58 x 47mm
Maximum power: 14.75 horsepower @ 10,000 rpm
Maximum torque: 8.3 ft-lbs @ 8000 rpm
Compression ratio: 12:1
Fueling: Magneti Marelli MIUG4 EFI w/ 32mm throttle body
Valvetrain: DOHC; 4-valve
Starting: Electric
Transmission: 6-speed
Final drive: Chain

CHASSIS

Frame: Twin-tube steel
Front suspension; travel: Non-adjustable 41mm inverted fork; 9.4 inches
Rear suspension; travel: Linkage assisted spring-preload adjustable shock; 8.3 inches
Wheel: Wire-spoke
Front wheel: 17 x 2.50 (RX: 21 x 1.85)
Rear wheel: 17 x 3.5 (RX: 18 x 2.15)
Tires: CST Magsport (RX: CST)
Front tire: 110/70 x 17 (RX: 90/90 x 21)
Rear tire: 150/60 x 17 (RX: 120/80 x 18)
Front brake: 300mm wave disc w/ floating dual-piston caliper (RX: 260mm disc)
Rear brake: 220mm wave disc w/ floating caliper
ABS: Bosch