The only thing more fun to ride than a KTM 250SX is a KTM
125SX. It’s a feather in the air and a rocket on the ground.
MXA’S 2018 KTM
250SX SETUP SPECS
This is how we set up our 2018 KTM 250SX for racing. We offer it as a guide to help you find your own
WP FORK SETTINGS
Out with the old and in with the new. WP AER air
forks are here to stay. As a general rule, first find an air
pressure that you like. Then, start adjusting the clickers.
We recommend adjusting the air pressure in 2-pound
increments. While the stock air pressure is 147 psi, we
had riders who liked it as low 143 psi and as high as 154
psi. With only one air-pressure adjustment, changes can
be made in half the time it takes to adjust a Showa or
Kayaba air fork. Plus, KTM gives you a digital air pump
when you buy the bike. It makes it easier to find your
happy place. These are the settings we ran on the 2018
KTM 250SX (stock settings in parentheses):
Air pressure: 144 psi (147psi)
Compression: 23 clicks out ( 12 clicks out)
Rebound: 19 clicks out ( 12 clicks out)
Fork height: 2nd line
Notes: On big hits at pressures below 144 psi, the
forks will bottom out (unless you add oil to the fork).
Anything above 144 psi and our testers had no issues
with bottoming resistance.
WP SHOCK SETTINGS
The KTM shock has a good setting. We spent most
of our time dialing in the forks, although sag played a
big part in balancing out the bike. We were all over the
map, going as low as 115mm and as high as 100mm.
Most test riders split the difference at 107mm, although
the sweet spot is between 102mm and 108mm, depending on the rider and track. For hardcore racing, we
recommend this shock setup for the 2018 KTM 250SX
(stock specs are in parentheses):
Spring rate: 42 N/m
Hi-compression: 1-1/4 turns out ( 2 turns)
Lo-compression: 8 clicks out ( 15 out)
Rebound: 14 clicks out ( 15 out)
Race sag: 107mm (110mm)
Notes: For riders below 185 pounds, start turning out
the low-speed compression to get the rear end to settle.
MIKUNI TX 38 JETTING SPEC
Here’s what we ran in our 38mm PWK (stock settings
Main jet: 440
Pilot: 45 ( 42. 5)
Air screw: 1/4 turn out (1-1/2 turns out) ❏
road, the tie-down hook can crimp the metal tube that
comes out of the front master cylinder.
( 7) Fork-air bleeder. Even if you own a #20 Torx
wrench, never use it on the air side of the WP forks. It will
strip out. Just use a 10mm T-handle. On the left side, you
have to use the #20 Torx.
( 8) ODI grips. We like the ODI lock-on grips, but, the
clutch side is locked on with a #15 Torx. If you want to
change the grips, you have to have a #15 Torx wrench.
( 9) Gas cap. It sticks.
( 10) Sprocket bolts. Watch the sprocket bolts closely.
They come loose all the time (Loctite or not).
( 11) Spokes. Our KTM spokes never take a set. We
check them constantly, even if the bike is just hit by a
gust of wind.
Q: WHAT DID WE LIKE?
A: The like list:
(1) Brakes. The best in the class.
( 2) Hydraulic clutch. KTM’s self-adjusting, hydraulic,
Belleville washer clutch is way ahead of the Japanese
( 3) Airbox. We don’t think changing an air filter could
get any simpler. Plus, with a few strips of tape, you can
turn it into a tuning tool.
( 4) Forks. We love the WP AER air forks.
( 5) Tires. The 250SX comes with our favorite tires, the
Dunlop Geomax MX3Ss.
( 6) Power valve. The power valve is a great way
to refine the power delivery. But, order a $95.00 Kreft
PowerDial so you can make incremental changes in seconds—without the need for a Robertson or Scrulox wrench.
( 7) Weight. The 2018 KTM 250SX hits the scales at 212
pounds without fuel (which is how the AMA weighs bikes).
Q: WHAT DO WE REALLY THINK?
A: We have long awaited this bike. The new-generation chassis with the reworked 250SX engine and the WP
AER fork make for a combination that puts the old-dog
YZ250 out to pasture. KTM is making two-strokes fun
again. The 2018 KTM 250SX is something you look forward
to riding each and every time. This bike is not just good;