2021 Motorcycle Previews 2021 KTM Motocross and Supercross Lineup First Look (8 Fast Facts)

2021 KTM Motocross and Supercross Lineup First Look (8 Fast Facts)

The 2021 KTM motocross and supercross lineup consists of six motorcycles—three each of four-strokes and two-stroke.

The four-stroke models are the 450 SX-F, 350 SX-F, and 250 SX-F, while the two-strokes are the 250 SX, 150 SX, and 125 SX. Most of the changes for 2021 apply to all six models, though there are some exceptions. Let’s take a quick look at the updates to the 2021 KTM motocrossers and supercrossers.

2021 KTM Motocross and Supercross Lineup First Look - 450 SX-F
2021 KTM 450 SX-F

  1. All six 2021 KTM SX-F models get a new WP Xact fork. While the fork remains an air-spring design, it gets new internals. The bypasses have been enlarged “to reduce pressure peaks,” according to KTM. Complementing that is a smaller rebound spacer in the air leg. That means more air volume in the negative chamber and a more linear action with a spring-style feel. Theirs is also a new mid-valve damping system that KTM says improves feedback and feel. Overall, the new WP Xact forks are claimed by KTM to have “refined performance, comfortable, and handling.”
  1. The WP Xact shock also gets a minor update. There’s a new link-piston O-ring, which KTM tells us will “reduce fading and improve consistency over long motos.”

    2021 KTM Motocross and Supercross Lineup First Look- 250 SX-F
    2021 KTM 250 SX-F
  1. There are new SKF bearing seals in the linkage for freer movement. KTM says this results in “better suspension feel and performance throughout the shock stroke.”
  1. With the suspension and linkage updates comes new settings. KTM isn’t revealing what’s new, but the company does say the result is “better traction, improved comfort and confidence-inspiring feel.”
  1. Dunlop Geomax MX33 tires are now shod on the Excel rims.
  1. The SOHC KTM 450 SX-F gets some motor updates not found on the DOHC 250 and 350. There’s a new con rod with a copper-beryllium upper bush for faster revving, along with new rocker arms up top for the titanium valves. The mapping has been changed to punch up the low-end power, and map 2 is now the “extreme performance option,” according to KTM. Also, the 450 gets a new hour-meter casing.

    2021 KTM Motocross and Supercross Lineup First Look - 250 SX
    2021 KTM 250 SX
  1. The two-strokes get two changes you won’t see in the four-strokes. Still working with carburetors, the 250 SX, 150 SX, and 125 SX have a new smoother roller-action throttle assembly. Also, the inner clutch hub sleeves are thicker to beef up reliability.
  1. KTM gives the 2021 125 SX a new piston. It is made of a harder material to increase durability while maintaining performance.

2021 KTM 450 SX-F (350 SX-F and 250 SX-F) Specs

ENGINE

  • Type: Single-cylinder four-stroke
  • Displacement: 450cc  (350 SX-F: 350cc; 250 SX-F: 250cc)
  • Bore x stroke: 95 x 63.4mm (350 SX-F: 88 x 57.5mm; 250 SX-F: 78 x 52.3mm)
  • Compression ratio: 12.75:1 (350 SX-F: 14.2:1; 250 SX-F: 14.4:1)
  • Valvetrain: SOHC, 4 valves (350 SX-F and 250 SX-F: DOHC, 4 valves)
  • Starting: Electric w/ Lithium-ion 12.8-volt 2 Ah battery
  • Lubrication: Pressure Lubrication with 2 Pumps
  • Fueling: Keihin EFI w/ 44mm throttle body
  • Transmission: 5-speed
  • Clutch: Wet multi-disc DDS clutch w/ Brembo hydraulics
  • Final drive: 5/8” x ¼” chain

CHASSIS

  • Frame: Central double-cradle chromoly steel
  • Subframe: Aluminum
  • Handlebar: Neken aluminum
  • Front suspension: Fully adjustable WP Xact inverted 48mm fork; 12.2 inches
  • Rear suspension: Linkage-assisted fully adjustable WP Xact shock; 11.8 inches
  • Wheels: Excel
  • Front wheel: 21 x 1.60
  • Rear wheel: 19 x 2.15
  • Tires: Dunlop Geomax MX33
  • Front tire: 80/100 x 21
  • Rear tire: 120/90 x 19
  • Front brake: 260mm disc w/ Brembo caliper
  • Rear brake: 220mm disc w/ Brembo caliper

DIMENSIONS and CAPACITIES

  • Wheelbase: 58.5 inches (± 0.4 in)
  • Rake: 26.1 degrees
  • Triple clamp offset: 22mm
  • Seat height: 37.4 degrees
  • Ground clearance: 14.6 inches
  • Fuel capacity: 1.85 gallons
  • Curb weight: 234 pounds (350 SX-F: 231 pounds; 250 SX-F: 229 pounds)

2021 KTM 250 SX (150 SX and 125 SX) Specs

ENGINE

  • Type: Single-cylinder two-stroke
  • Displacement: 249cc (150 SX: 144cc; 125 SX: 125cc)
  • Bore x stroke: 66.4 x 72mm (150 SX: 58 x 54.5mm; 125 X: 54 x 54.5mm)
  • Starting: Kick
  • Lubrication: Premix @ 40:1
  • Fueling: 38mm Mikuni TMX carburetor
  • Transmission: 5-speed (150 SX and 125 SX: 6-speed)
  • Clutch: Wet multi-disc DDS clutch w/ Brembo hydraulics
  • Final drive: 5/8” x ¼” chain

CHASSIS

  • Frame: Central double-cradle chromoly steel
  • Subframe: Aluminum
  • Handlebar: Neken aluminum
  • Front suspension: Fully adjustable WP Xact inverted 48mm fork; 12.2 inches
  • Rear suspension: Linkage-assisted fully adjustable WP Xact shock; 11.8 inches
  • Wheels: Excel
  • Front wheel: 21 x 1.60
  • Rear wheel: 19 x 2.15
  • Tires: Dunlop Geomax MX33
  • Front tire: 80/100 x 21
  • Rear tire: 110/90 x 19 (150 SX and 125 SX: 100/90 x 19)
  • Front brake: 260mm disc w/ Brembo caliper
  • Rear brake: 220mm disc w/ Brembo caliper

DIMENSIONS and CAPACITIES

  • Wheelbase: 58.5 inches (± 0.4 in)
  • Rake: 26.1 degrees
  • Triple clamp offset: 22mm
  • Seat height: 37.4 degrees
  • Ground clearance: 14.8 inches
  • Fuel capacity: 2.0 gallons
  • Curb weight: 222 pounds (150 SX and 125 SX: 205 pounds)

2021 KTM Motocross and Supercross Lineup Photo Gallery

 

Don Williams
Don Williamshttp://www.ultimatemotorcycling.com
With 50 years of riding experience, Don Williams is a fan of all kinds of motorcycles. He enjoys sport bikes, cruisers, dirt bikes, touring bikes, adventure bikes, dual sport bikes, and rideable customs. Ask Don what his favorite bike is and he will tell you, "Whatever bike I'm on."

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