…except for, perhaps, the new KTM 150 SX.
Basically, the 125 SX got an all-new motor that was designed to be powerful, compact and light. KTM says the motor is 4.4 pounds lighter than the previous mill. It still utilizes a six-speed transmission with the same ratios as before, but the tranny itself is lighter and narrower. The exhaust system has been tuned specifically for the SX 125 and the SX 150, so they are not exactly the same.
The SX 125 and 150 share the same new chromoly steel frame and chassis as the entire SX-F line, which is borrowed from the 2015 250 and 450 SX-F Factory Edition models. The two-strokes also have smaller and lighter subframes and new swingarms, as compared to the previous models. The small-bore SXs also share “No Dirt” footpegs and shiftlevers that are designed not to clog with mud.
The 125 and 150 SX also feature CNC-machined upper triple clamps with rubber mounts for the Neken handlebars, which also feature ODI lock-on grips.
Like their bigger brothers, the little SX are fitted with WP 4CS forks and WP’s latest generation shocks, mounted to new linkage/pull-rod systems.
The bikes also feature super lightweight Galfer Wave rotors, CNC-machine hubs and high-end Excel rims fitted with Dunlop GEOMAX MX32 tires.
In case you’re wondering, the 2016 250 SX two-stroke did not get a new motor this year, nor did it get the new frame that the rest of the SX and SX-Fs got.
QUICK SPIN
When KTM recently introduced its all-new line of four-stroke SX-F and XC-F motocross and off-road bikes to the media at Ironman Raceway in Crawfordsville, Indiana, they also brought along the 125 and 150 SXs for us to try out. Mixing small-bore two-strokes with big-bore four-strokes is sometimes a bit of a challenge and takes some getting used to (especially going from a four-stroke to a two-stroke), but it’s a lot easier when the little zingers put out so much power, which narrows the two-stroke/four-stroke gap a bit, especially with the 150 and its extra torque.
Both the 125 and 150 SXs are extremely fast machines and super fun to ride; after all, who doesn’t like holding the throttle wide open all the way around the track? The 125 SX loves to be screamed and when you do, you’re rewarded with high-revving power that keeps you grinning from ear to ear. Putting all that power to the ground efficiently, however, can be a bit of a challenge on a hard-packed and slick track compared to a 250F, as you are constantly trying to find that fine line between full traction and sudden wheel spin, but with the KTM, it’s made easier since it has such a broad and useful powerband—for a 125. It also has decent bottom end so if it does fall off the pipe a bit, you can quickly clutch-it back up to the sweet spot again.
Having a bit more power and noticeably more torque than the 125 SX, the 150 SX’s motor is easier to manage and control from bottom to mid. It too is very fast on top, so the very best way to ride the 150 (as well as the 125 for that matter) is to just keep it pinned as much as you can.
Both the 125 and 150 SX have similar handling characteristics (which is excellent), and they both feel ridiculously light, which is their greatest attributes, of course. At a claimed 196 pounds (without fuel), you can really flick these bikes around both on the ground and in the air.
We plan on spending a lot more time on these bikes down the road, but our first taste of the new 2016 KTM 125 and 150 SXs left us wanting more.
The 125 and 150 SXs have the same frame and chassis as the rest of the SX-F line.
SPECIFICATIONS
KTM 125/150 SX
Engine Type: Single cylinder, 2-stroke
Displacement: 124.8cc/143.99
Bore x stroke: 54.0 x 54.5mm/58.0 X 54.8mm
Starter: Kickstarter
Transmission: 6-speed
Fuel System: Keihin PWK 38S carburetor
Lubrication: Premix 40:1
Primary Ratio: 23:73
Final Drive: 13:50
Cooling: Liquid
Clutch: Wet multi-disc clutch, Brembo hydraulics
Ignition: Kokusan
Frame: Central double-cradle type steel
Subframe: Aluminum
Front Suspension: WP 4CS
Rear Suspension: WP monoshock with linkage
Front Wheel Travel: 11.81 in.
Rear Wheel Travel: 11.81 in.
Front Brake: 260mm disc
Rear Brake: 220mm disc
Front Rim: 1.60x 21 in. Excel
Rear Rim: 2.15 x 19 in. Excel
Front Tire: 80/100-21 in. Dunlop Geomax MX32
Rear Tire: 100/90-19 in. Dunlop Geomax MX32
Wheelbase: 58.5 in.
Ground Clearance: 14.8 in.
Seat Height: 37.8 in.
Fuel Capacity: 1.9 gal.
Weight (without fuel): 196.7 lbs
