2025 KTM SX Lineup First Look: 300, 250, 150, 125 [11 Fast Facts]

April 13, 2024

2025-KTM-250-sx-first-look-motorcross-motorcycle-1 — 250.

The 2025 KTM SX lineup of two-stroke motocross bikes gets its most significant updates since 2023. There are four 2025 SX models—300, 250, 150, and 125—and all get the same updates. Yes, you read right—the 150 is back. With that in mind, let’s check out what’s new for ’25 in the KTM SX four-bike lineup.

2025 KTM SX Lineup First Look: 150 — 150.

A new frame is deployed on the 2023 KTM SX lineup, and it’s almost 11 ounces lighter. The four motocrossers get a frame with a new wall thickness for the chromoly steel tubing. Additionally, the front triangle and shock mount have been revised. A KTM insider tells us that the changes are intended to provide “improved comfort and control.”

2025 KTM SX Lineup First Look: 300 — 300.

There are new mounts for the two-stroke motors. The mounts fine-tune the flex of the chassis. KTM tells us this update is “for improved cornering.”

2025 KTM SX Lineup First Look: 250 and 300 cases — 250 and 350 cases.

A new fuel tank roll is intended to meet several goals. We’re told by KTM that the new fitment provides more durability by reducing frame scrubbing by the tank. The tank shrouds are also new, directing more air to the radiator.
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The rear suspension gets reworked. In addition to the new shock mount, there is also a new linkage assembly for the WP Xact shock. With those changes come new shock settings, including a damping increase. Our sources say that “comfort” is the primary goal.

2025 KTM SX Lineup First Look: 125 — 125.

With new rear suspension parts and a changed frame, the WP Xact fork gets revised. There are new settings to enhance the frame changes.

There’s even more going on with the swingarm—a new chain slider. Our source at KTM reveals that it “improves durability and dirt dissipation.”

A new air inlet sleeve and snorkel design is now one-piece. The material is beefed up to reduce deformation that can reduce power output.
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KTM engineers worked on the rear brake pedal. The new design is claimed to be more durable.

There are plenty of returning parts from respected providers. Keihin handles the EFI with a 39mm throttle body. Brembo takes care of the brakes and the hydraulics for the shock. Excel rims are laced to CNCed hubs. Dunlop Geomax MX34 tires are standard.

When it comes to appearance, there is an orange takeover. One look at the photos tells you that. What you might not notice is that the graphics are molded into the plastic for durability.
We don’t have prices yet. However, you can see the 2025 KTM SX lineup at your local dealer next month.

2025 KTM 300 SX, 250 SX, 150 SX, and 125 SX Specs

ENGINE

Type: Single-cylinder 2-stroke
Displacement: 293cc (250: 249cc; 150: 144cc; 125: 125cc)
Bore x stroke: 72 x 72mm (250: 66.4 x 72mm; 150: 58 x 54.4mm; 125: 54 x 54.5mm)
Starter: Electric
Fueling: Keihin EFI w/ 39mm throttle body
Lubrication: Premix @ 60:1 (125: 40:1)
Transmission: 5-speed (125: 6-speed)
Clutch: Wet multi-disc DDS clutch w/ Brembo hydraulics

CHASSIS

Frame: Central double-cradle chromoly steel w/ aluminum/polyamide subframe
Handlebar: Tapered aluminum Neken
Front suspension; travel: Fully adjustable WP Xact AER 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 MX34
Front tire: 80/100 x 21
Rear tire: 110/90 x 19 (150 and 125: 100/90 x 19)
Front brake: 260mm disc
Rear brake: 220mm disc