KTM 125 SX
Price: $5998
Claimed Weight (no gas): 200 lb
Seat Height: 38.8 in.
Fuel Capacity: 2.1 gal.
KTM's smallest full-size motocrosser gets all of the great suspension advances that have catapulted its four-stroke brothers up in comparison rankings, and the upgrade seems to have done the same thing for our test riders on the 125 SX (and 150 SX as well). And that is only complemented by an engine that is putting out the kind of power it took to take down four-strokes for the 125cc Outdoor National title in 2003. The KTM 125 has a very smooth-building power spread that has an exceptional amount of torque and a slower-revving build that is very novice friendly. That lower part of the power is not where you'd race the bike or where an experienced pilot would ride it, but it is there and something novices will appreciate. But once you get the bike up into the revving portion of the powerband it really comes alive-but smoothly, and it pulls long and hard all the way through a great top-end. There is plenty of overrev, and it can scream or pull the next shift with ease. Jetting was perfect and crisp, and the hydraulic clutch action was as good as it gets.
The KTM 125 has a very light feel, the lightest of the bikes in this group. It also has great steering and turning, letting the rider go anywhere on the track. The suspension seemed set perfectly for riders in the 150-160 pound range but wasn't so stiff that our lighter riders got bucked around too much. And like its bigger brothers, the bottoming was controlled, even with our tanky 180-190 pound riders. The SX is thin and the rider compartment is widely adjustable with a multiposition top triple clamp.
KTM 150 SX
Price: $6198
Claimed Weight (no gas): 200 lb
Seat Height: 38.8 in.
Fuel Capacity: 2.1 gal.
The bigger brother to the 125, the 150 SX is a lot more different than the added 25cc might suggest. There isn't much more torque on the bottom, in fact it feels like there is a little less. But when this bike comes alive in the midrange it really comes alive. It definitely feels like it is trying to bridge the gap between 125cc and 250cc two-strokes to 250cc four-strokes when it pulls like this (it feels stronger than even the KTM 200cc!), and it likes to lift the front wheel when you're hooked up and hauling. It is so aggressive that riders often needed to control the power with the clutch, not just boost it with that lever. The bike continues to pull hard up into the top, and it feels faster, as expected, than the 125. This is an expert-level type of power, and it is trying to keep pace with 250cc four-strokes. It might just be able to do that if the rider is quick enough with the shifting, but it will be a lot of work. For less experienced riders, look into flywheel weights to tame the little beast!
With the added power the bike's suspension is asked to work harder, still this KTM delivers. Since the front wheel always seemed lighter, more attention was focused on the rear, and some of the lighter riders felt the 150 getting a little unstable on the choppy high-speed straights. The bike only feels slightly heavier in the flick and fling department, but it isn't actually heavier on the scale. The added power gives the bike a heftier feel when you are on the throttle. The brakes, like on both of these KTMs, are incredibly strong and have good control once you get used to the strength. The stock tires are intended for softer terrain, and work great if you have loam though they can be slippery on hardpack after just a little wear.