Pucker up: This 260mm Brembo front brake can stop a Rhino
or 450SXF, so imagine what it can do on a 150cc two-stroke.
( 5) Pipe. We originally thought that KTM had built a
special pipe for the 150SX because KTM’s website photos
showed two different pipes. This was wrong.
( 6) ECU. The ECU is the standard KTM unit, but the
150SX has different mapping.
( 7) Jetting. The 150SX has a bigger main and pilot jet,
as well as a different needle.
Q: HOW FAST IS THE 2016 KTM 150SX?
A: When it comes to power to the ground, the KTM
150SX can run with any 250F powerplant. The issue isn’t
how much power the 150SX has, but the nature of its
high-rpm powerband. Compared to a four-stroke powerband, the 150SX’s feels peaky and narrow. When the dirt
offers decent traction, the 150SX can run with 250 four-strokes, but it takes a talented rider to stay on the 11,500
rpm peak. Helping it stay competitive is its 198-pound
dry weight (without fuel in the tank). That is over 20
pounds lighter than any 250cc four-stroke, even the
ultra-light KTM 250SXF.
To successfully use the 150SX as a race bike, you have
to take the temperament of the engine into consideration.
The engine revs quickly, makes its best power in the top
end and signs off fast (it makes its max power at 11,500,
and 500 rpm later it’s a weak sister). Selecting the proper
shift points is key to keeping this smoker in the meat of
the power. In some ways the potent power curve makes
the 150 harder to ride than a 125. In the past most MXA
test riders choose to race the KTM 125SX over the 150SX
because it had a more organic powerband, cleaner shift
points and better transitions through the midrange. Now,
for 2016, with a few extra ponies added to the 150SX’s
power profile and a gearing change, our testers are
starting to lean the other way.
Q: HOW DOES THE 2016 KTM 150SX RUN ON
A: Hold on to your hats! The 2016 KTM 150SX makes
a whopping 40. 60 horsepower and 18. 63 foot-pounds of
torque on the dyno. That is the exact amount of horsepower that the 2015 Yamaha YZ250F made. Plus, the 2016
KTM 150SX makes almost 2 horsepower more than its
2015 brethren. If you compare the 2015 KTM 150SX to the
2016 KTM 150SX on the dyno, they are a fair match from
6000 rpm all the way to 11,000 rpm. Then—whammo!—the
2016 model takes off like a scalded cat, while the 2015
model begins to fade. The 2015 KTM 150SX peaks at
38. 81 horsepower at 11,000 rpm, while the 2016 model
peaks at 40. 60 at 11,500 rpm. Even more telling, at 12,000
rpm the 2015 bike is making 32. 90 horsepower, while
the new model is still pumping out 38.00 horsepower.
Horsepower is up, peak is moved up 500 rpm, and sign-off, albeit drastic after 12,000 rpm, is later. No matter how
you slice it, this is one powerful two-stroke.
Q: IS THE 2016 KTM 150SX SUSPENSION
BETTER THAN THE 2015 SUSPENSION.
A: Yes, but not just due to the updated WP suspension. Last year’s chassis was old technology, albeit only a
couple years old, but it made the previous WP suspension
feel worse than it actually was. The all-new chassis and
suspension components allow the 2016 KTM 150SX to
handle leaps and bounds better than in previous years.
Both the front and rear suspension are plush from the top
of the stroke to the bottom. Our biggest bugaboo was
that with an aggressive rider on a track with big jumps,
the forks could and would bottom out. For the light,
Record breaker: At 40. 60 horsepower the KTM 150SX has the
oomph to get the 198-pound bike over big gaps.