When you've graduated from the introductory dirt bikes in KTM's->ke1954 line-up, the next step is riding a junior bike that has championship tradition. Kind of like the KTM 125 SX.->ke3069

Those wanting to race in the Junior World Championship need look no further than this beauty to stay competitive. The free-revving and lively two-stroke engine has gained even more performance for the current season. If you thought that the 125 SX's 125cc 1-cylinder 2-stroke engine was impressive, its newly developed exhaust expansion chamber has not only improved in quality, but it now comes with an optimized soundbox that ensures an extra shot of engine power that's explosive and dependable, all at the same time.

The 125 SX also comes with a completely revamped frame made from high-quality chrome-molybdenum steel that's extremely light and torsion-resistant. The bike is also characterized by a particularly balanced geometry that combines playful handling with razor-sharp precision. The two-strokes in the MX range from KTM are also now equipped with an elaborate linkage rear suspension system.

Linking the shock absorber via a lever system provides high progressiveness and wide adjustment ranges. Apart from the new linkage rear suspension, there is the new cast aluminum swingarm, which is designed for minimum weight while supplying optimum lateral stiffness and defined longitudinal flexibility. This makes a major contribution to the 125 SX's excellent tracking stability, playful handling, and extreme traction, making for a bike that's got plenty of substance to back up its long-standing tradition as a motocross bike that has a history of championship-winning performances.

Find out more about the KTM 125 SX after the jump.

2012 KTM 125 SX

Specifications
  • Make: Array
  • Model: 2012 KTM 125 SX
  • Engine/Motor: Single cylinder, 2-stroke
  • Transmission: 6 gear, claw shifted
  • [do not use] Vehicle Model: Array

Engine

The 125 SX's flow-optimized intake flange between airbox and carburetor now ensures even better charging with fresh gas. This results in even freer revving and even more power in all rev ranges for the liquid-cooled, two-stroke machine.

New Exhaust Expansion Chamber

The 125 SX's new exhaust expansion chamber has not only improved in quality; in conjunction with the two-stroke machine's exhaust control system, its optimized soundbox ensures an extra shot of engine power - explosive, but dependable.

New Frame and Suspension

The 125 SX's completely revamped frame made from high-quality chrome-molybdenum steel is not only extremely light and torsion-resistant. It is also characterized by a particularly balanced geometry that combines playful handling with razor-sharp precision.

The two-strokes in the MX range from KTM are now also equipped with the elaborate linkage rear suspension system. Linking the shock absorber via a lever system provides high progressiveness and wide adjustment ranges. The 125 SX therefore has a season ticket for the podium, even on the most brutal motocross courses.

Apart from the new linkage rear suspension, there is the new cast aluminum swingarm, which is designed for minimum weight while supplying optimum lateral stiffness and defined longitudinal flexibility. This makes a major contribution to the 125 SX's excellent tracking stability, playful handling and extreme traction.

Bodywork

The 125 SX's bodywork with the very slim seat and spoiler lines, plus excellent contact points, perfects the bike's ergonomics, making handling even simpler and more precise.

New Exhaust Expansion Chamber

The 125 SX's new exhaust expansion chamber has not only improved in quality; in conjunction with the two-stroke machine's exhaust control system, its optimized soundbox ensures an extra shot of engine power - explosive, but dependable.

New Exhaust Expansion Chamber

The further improved upside-down telescopic fork incorporating closed-cartridge technology now ensures even greater punch with a somewhat tauter setting. At the same time, the WP fork with 48 mm (1.89 in) outer tube diameter bolsters the playful handling of the 125 SX.

New Telescopic Fork Setting

Design

1-cylinder 2-stroke engine, water-cooled, with reed intake and exhaust control

Displacement

124.8 cm³ (7.616 cu in)

Bore

54 mm (2.13 in)

Stroke

54.5 mm (2.146 in)

Starting aid

Kickstarter

Transmission

6 gear, claw shifted

Primary gear

23:73

Final drive

13:50

Clutch

Wet multi-disc clutch / hydraulically operated

Ignition system

Contactless, controlled, fully electronic ignition system with digital ignition timing adjustment, type Kokusan

Frame

Central tube frame made of chrome molybdenum steel tubing

Forks

WP Suspension Up Side Down 4860 MXMA CC

Shock absorber

WP Suspension 5018 BAVP DCC

Suspension travel Front

300 mm (11.81 in)

Suspension travel Rear

330 mm (12.99 in)

Brake system

Disc brakes, brake calipers on floating bearings

Brake discs - diameter Front

260 mm (10.24 in)

Brake discs - diameter Rear

220 mm (8.66 in)

Chain

5/8 x 1/4"

Steering head angle

63.5°

Wheel base

1,480±10 mm (58.27±0.39 in)

Ground clearance (unloaded)

395 mm (15.55 in)

Seat height (unloaded)

992 mm (39.06 in)

Total fuel tank capacity approx.

7.5 l (1.98 US gal)

Unleaded premium fuel, mixed with 2-stroke engine oil (1:40)

Weight without fuel approx.

91.6 kg (201.9 lb.)


Specifications

Motorcycle-USA----"Precise handling and extreme traction is being supplied by the optimum lateral stiffness and defined longitudinal flexibility from minimum weight due to the new linkage on the rear suspension. The KTM 125 SX has extremely well handling and traction."