VOL. 52 ISSUE 13 MARCH 31, 2015 P91
For all intents and purposes, the 2015 250
SX-F Factory Edition is an all-new motorcycle. It
has almost nothing in common with the standard
version; only a handful of parts are interchange-
able, if that many. KTM engineers addressed
three main issues in designing the FE: reduc-
ing weight, improving mass centralization and
improving overall performance.
Weight reduction was the major priority,
though. They pretty much scrutinized every
part on the bike and found ways to make them
lighter, and the end result is the lightest 250F
production bike on the market right now at a
claimed 221 pounds (without fuel), and KTM
swears that this number is accurate. (We have
no reason not to believe them after riding it
for the first time—this bike feels light.) KTM's
claimed dry weight for the standard 250 SX-F
is 225.3 pounds; our 2015 250 SX-F test
bike weighed 241 pounds on our scale with its
1.98-gallon fuel tank topped off. (We have not
yet had the chance to weigh the FE.)
A big chunk of the FE's weight reduction
comes from its four-valve, SOHC, fuel-injected
motor, which is now 2.4 pounds lighter than the
old motor, and it's significantly smaller and more
compact in size. Some of the motor changes
include raising the crankshaft 6mm, reducing
the length of the connecting rod 6mm, lighten-
ing the camshafts 150 grams, moving the clutch
11.1mm rearward and 26.9mm up, and giving the
finger followers a new DLC coating that is said
to be 30 percent harder. The cylinder is also
130 grams lighter and the big-end bearing has
been redesigned to withstand the SX-F's higher
14,000-rpm rev limit.
The five-speed transmission has been
tweaked, as well. It is overall 8mm narrower and
features a new surface treatment on the first and
fifth gears along with a special low-friction coating
on the shift forks to provide smoother and more
precise shifting. The steel one-piece basket also
has one less plate (now seven), and the master
cylinder has been modified for a lighter pull.
