2009 sees the introduction of the all-new KTM 150 SX, apparently a "new" two-stroke dirt bike, but in fact an upgraded and renamed 144 SX. Like its inspiration model, the 150 SX brings the best of the 125 cc and 250 cc worlds in an incomparable product characterized by extreme ease of handling and serious two-stroke power to work with. It stands as the choice of middle, an uncompromising one, for dirt riders who know exactly what they request from a bike.

  • 2009 KTM 150 SX
  • Year:
  • Make:
  • Model:
  • Engine:
    Single cylinder, 2-stroke
  • Transmission:
    6 Gears
  • Horsepower @ RPM:
    40 hp
  • Energy:
    Keihin PWK-S 38 AG
  • Displacement:
    143.6 L
  • Top Speed:
    110 mph
  • Price:



KTM is into offering diversity and we couldn’t get a better example than the 150 SX. This thing is being powered by the liquid-cooled, 143.6 cc, single-cylinder, two-stroke engine, which is perfectly capable of translating its torque and horsepower into a greater rush than that provided by any of the 250 cc, four-stroke dirt bikes out there, including KTM’s 250 SX-F. That is why the Austrian engineers have mounted the engine on the extremely competitive chassis, one that is slightly different than on the previous generation model and even more agile.

The seat is now positioned at 38.78 (rather than at 36.42) inches from the ground and it stands for a seriously sized dirt bike destined to riders fitting the same description. The ground clearance level hasn’t been modified, neither the wheelbase nor the steering angle. Still, it does feature a 2.11 gallons tank instead of the previous 1.98 gallons one.

2009 KTM 150 SX
- image 299139
2009 KTM 150 SX

What really helps us call the 150 SX a competition bike is the suspension equipment composed from the 48 mm WP USD fork providing 11.81 inches of wheel travel and the WP PDS shock absorber that is capable of an even more impressive 13.19 inches of wheel travel. The brakes aren’t at all disappointing as the 150 SX works with petal-style discs (260 mm front and 220 mm rear) mounted on the Excel wheels that are by now a consecrated KTM feature.

Both in apparel and performance, this two-stroke bike lines up perfectly to modern requirements of the market, but we’ve come to find that the fact of it being new has nothing to do with that.


2009 KTM 150 SX
- image 299143
2007 KTM 144 SX

In fact, the bike was brand new back in 2007 when it was first introduced as the KTM 144 SX and the biggest change, really, in 2009 is the name. Originally, it came in to fill the gap between the 125 SX and the 250 SX and its name was determined by the engine’s displacement. Although that didn’t changes in 2009, we’re seeing that number being rounded up.


Filling in the gap between the 125 SX and 250 SX, it would be natural for the 150 SX to look like a combination between the two models, but that’s not the case with dirt bikes. In fact, the three look almost identical, the engine being the biggest difference and that doesn’t stand out from the visual point of view. What makes the KTM 150 SX so great is that, from the very first glance, it stands as an indicator of its capabilities. A veritable mountain goat featuring large diameter wheels (21-inch front and 19-inch rear) with high mounted and aggressive fenders, the bike is built for harsh landings and soaking up bumps.

2009 KTM 150 SX
- image 299140
2009 KTM 150 SX

The Austrians name this an “Off-road Competition” bike and considering that it doesn’t feature a headlight, KTM’s description is very accurate. So you’re supposed to get both an off-road and a motocross machine wrapped up in the aggressive side panels featuring orange decals and the manufacturer’s name. Masking the already small silencer are the side number plates, which are white for a racier look. In between those and the seat you’ll read “150 SX” and go like “yeah, it’s exactly the model I thought it was”.

As before mentioned, the seat is pretty tall (38.78 inches from the ground) and the rider will grab on the Renthal aluminum bars while supporting on the almost middle-mounted pegs. So, due to the also aggressive riding position, the 150 SX inclines more on the motocross side rather than on the off-road one. That’s also what we’ve come to find during last year’s test run, which is reflective to this day as performance figures haven’t been modified and neither the overall weight (200.2 lbs) of the new model.

Test Ride


The 2009 KTM 150 SX comes with a $6,198 MSRP which positions it, indeed, in between the models that lead to its creation, but I’m having a feeling that it isn’t the price that determines people to buy this model.


It’s all about the riding excitement that only two-stroke engines can deliver across their sweet power and torque curves combined with the excellent handling capabilities that the chassis is capable of. Although this is a new model, KTM is experienced in developing two-strokes so built quality and reliability reach the highest levels for the respective type of motor.


2009 KTM 150 SX
- image 299141
2009 KTM 150 SX


Engine and Transmission

Engine type: Single cylinder, 2-stroke
Displacement: 143.6 cc
Bore x stroke: 56 x 58,5 mm (2.20 x 2.30")
Starter: Kickstarter
Transmission: 6 Gears
Carburetor: Keihin PWK-S 38 AG
Control: Exhaust control
Lubrication: Mixture oil lubrication 1:40
Transmission oil: Motorex, SAE 15W50
Primary drive: 23:73
Final drive: 14:50
Cooling: Liquid cooled
Clutch: Wet multi-disc clutch, operated hydraulically
Ignition: Kokusan

Chassis and Dimensions

Frame: Cental double-cradle-type 25CrMo4
Subframe: Aluminium
Handlebar: Renthal, Aluminium Ø 28/22 mm (1.10 / 0.87")
Front suspension: WP USD Ø 48 mm (1.89")
Rear suspension: WP PDS shock absorber
Suspension travel front/rear: 300 / 335 mm (11.81 / 13.19")
Brakes, front/rear: Disc brakes 260 / 220 mm (10.24 / 8.66")
Rims, front/rear: 1,60 x 21"; 2,15 x 19" Excel
Tires, front/rear: 80/100-21"; 100/90-19"
Chain: 5/8 x 1/4"
Main silencer: Aluminium
Steering head angle: 63°
Wheel base: 1471 ± 10 mm (57.91" ± 0.39")
Ground clearance (unloaded): 390 mm (15.35")
Seat height: 985 mm (38.78")
Tank capacity: approx. 8 Liter (2.11 gal)
Weight (no fuel): approx. 90,8 kg (200.2 lbs)

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