2016 KTM 125 SX & 150 SX Two-Stroke First Ride

Adam Booth | June 15, 2015

MotoUSA just got back from Crawfordsville, Indiana where we had the chance to ride all the new 2016 KTM motocross bikes, including the all-new 125 SX and 150 SX two-strokes on the Ironman Raceway Motocross track. The new 125 SX and 150 SX have lost some serious weight and gained power. Thankfully KTM continues to push two-stroke technology, helping solidify the future for these small cubic centimeter screamers. 125s offer outstanding power-to-weight ratio, low cost and simplicity, which is great for young riders, those on a budget or riders who just simply love to ride a screaming two-stroke.

2016 KTM 125 SX

2016 KTM 125 SX Two-Stroke
Ripping around a national caliber track like the Ironman Raceway is the definition fun, especially on a 125 and 150cc two-stroke! The all-new KTM 125cc engine for 2016 is nothing like the 2015 powerplant, it was designed and built using the latest KTM engineering and technology. It now weighs 4.4 less and is lighter and much more compact. The changes to the engine also produce better power throughout the rpm range. Adding to the long list of changes and improvements is the all-new chassis, shared with the rest of the 2016 SX-F line. The new chassis combined with the more compact and powerful engine makes both the 125 SX and 150 SX pure bliss to ride.

2016 KTM 150 SX

For 2016 an all-new and lighter engine (just like the 125 SX but with an added 25ccs) produces more torque and power and lives in a totally new chassis, like the 125 SX. In fact there isn’t much difference between the two bikes, they are separated by 25ccs and a slightly different exhaust pipe. The 150 SX has the agility of the 125 SX but with more power and torque all the way the power curve, making the 150 SX, dare we say, even more fun to ride!

Pin It To Win It

If we didn’t mention it already, the 125 SX and 150 SX are hugely fun to ride and with the right rider can turn some incredibly fast laps. Of course when the dirt is deep and the hills steep a 250F has the advantage, but with the lighter weight and improved handling for 2016 the temptation to ride and enjoy a small bore two-stroke should be stronger than ever. A 125 or 150 is the perfect transition bike for a rider stepping up to big bikes from a 85cc mini bike or a smaller lighter rider.

The 125 SX and 150 SX share the same handling characteristics, shining in the ability to rail a corner, whether it be on the inside rut or screaming around the outside. The lightweight is most evident when it comes to direction change and maneuvering in the air. 150 SX is just as impressive in the handling department as the 125 SX with the added bonus of a little more torque and horsepower, helping it to rip out of corners and get over some jumps the 125 SX comes up just a bit short. The 150 SX is just an all around amazing bike and a blast to ride thanks to stronger bottom and long pulling top end. When a bike is as light as the 125 SX and 150 SX small shortcomings in the suspension are easily overlooked and don’t affect performance as much as on a heavier bike. The WP suspension worked well in Indiana on the Ironman MX track but it never really got very rough. We will be doing a full test on both bikes on all our rough familiar southern California tracks very soon, but as we’ve found out through testing the Factory Edition bikes with this new chassis and suspension, it is much improved over the 2015 models. Until then, mix some gas and have some fun riding.

 

4 Photos

KTM 125 SX/150 SX Highlights And Changes
• New 125 SX/150 SX engine is more compact, weighs four pounds less and has more power
• New cylinder with revised ports and newly designed power valve unit with a sophisticated mechanism for the lateral exhaust ports improves performance over the entire rpm range
• A new piston is optimized for maximum reliability with a reworked shape to fit perfectly with the new cylinder layout
• Lighter crankshaft is optimally balanced for minimum vibrations
• All-new die-cast engine cases raise the crankshaft and clutch shaft, centralizing mass and improving handling
• New 6-Speed transmission provides the same gear ratios as before but is lighter and narrower
• New exhaust pipe has been tuned for the 150 SX specifically to get maximum power output from the new engine
•New “No Dirt” shift lever prevents dirt from fouling the lever joint to ensure proper shifting in any condition
• New lighter Chromoly steel frame provides higher torsional rigidity with less longitudinal stiffness resulting in improved handling and energy absorption
• New smaller, lighter subframe design made with new aluminum profiles
• New lighter swingarm features a revised internal structure to match the new frame characteristics
• New lighter “No Dirt” footpeg design that provides a larger surface area and features a “scraper” to reduce dirt build-up in the hinge
• New CNC machined upper triple clamp featuring a rubber damping system for the new Neken handlebar and ODI lock-on grips
• The advanced WP 4CS (Four Chamber System) fork has been specifically designed for motocross and features revised damping settings optimized for the new chassis

KTM 125 SX Two-Stroke
Engine Type: Single Cylinder, 2-Stroke
Displacement: 124.8 cc
Bore / Stroke: 54.0 x 54.5 mm
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 Cooling
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
Suspension Travel Front/Rear: 11.81 in /11.81 in
Front/Rear Brakes: Disc Brake 260 mm/220 mm
Front/Rear Rims: 1.60x 21”, 2.15 x 19” Excel
Front/Rear Tires: 80/100-21”, 100/90-19” Dunlop MX32
Wheelbase: 58.5 in
Ground Clearance: 14.8 in
Seat Height: / 37.8 in
Tank Capacity, 1.9 ga
Weight (without fuel), Approx: 196.7 lbs

KTM 150 SX Two-Stroke
Engine Type: Single Cylinder, 2-Stroke
Displacement: 143.99 cc
Bore/Stroke: 58 x 54.8 mm
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 Cooling
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
Suspension Travel Front/Rear: 11.81 in /11.81 in
Front/Rear Brakes: Disc Brake 260 mm/220 mm
Front/Rear Rims: 1.60x 21”, 2.15 x 19” Excel
Front/Rear Tires: 80/100-21”, 100/90-19” Dunlop MX32
Chain: 5/8 x 1/4 in
Silencer: Aluminum
Steering Head Angle: 26.1º
Triple Clamp Offset: 22 mm
Wheelbase: 58.5 in
Ground Clearance: 14.8 in
Seat Height: 37.8 in
Tank Capacity: 1.9 gal
Weight (without fuel): Approx: 196.7 lbs

 

avatar

Adam Booth

Off-road Editor | Articles | Enjoying single track in the mountains, hitting the motocross track or battling an EnduroCross track, if it's on two wheels Boothy will have a smile on his face. Adam has served a mega ton of years in the off-road industry as a photographer, writer and popper of wheelies.

Facebook comments