KTM Motorcycle tests
1. Fork oil height. KTM did lower the oil height for 2009 over 2008, just not enough. We drained 15cc of oil to reduce the midstroke harshness.
2. Shock. For
riders above 165 pounds, the stock 6.9 kg/mm spring
works well. Lighter riders need a softer 6.6 kg/mm spring (found stock
on the 2008 250SXF).
3. Gearing. Of all
the 250 four-strokes, the KTM 250SXF is helped most by adding a tooth
to the rear sprocket. We swapped the stock 48-tooth sprocket for a
49-tooth sprocket. For Supercross-style tracks we have been known to add two teeth.
4. Accelerator pump.
The 39mm Keihin carburetor has good baseline settings with the mainjet,
pilot, needle and clip, but the accelerator pump is off. It causes a
noticeable hesitation off the bottom, which we resolved by turning the
accelerator pump screw 1/4 of a turn out from contact. We also added an
R&D Powerbowl2 and an R&D Flex-Jet to gain an adjustable fuel
screw and leak jet (unlike the 450SXF, the 250SXF does come stock with
a leak jet). www.r1dean.com
Clip position: Fourth from top
Fuel screw: 1/4 turn (1 turn)
Notes: KTM switched from an OBETP needle in 2008 to a OBEKP for this year, which is substantially richer.
5. Side panels.
KTM’s side panels aren’t large enough to accommodate full-size racing
numbers. Simply sticking numbers on the bike looks awkward, so we used
DeCal Works preprinted numbers (www.decalmx.com). The installation process was easy and
the preprints gave the 250SXF a very professional look.
6. Tires. The
stock Bridgestone M59/M70 tire combination is good, but the tires are
rather outdated. After wearing out the stock rubber, we switched to
Dunlop 756 tires.
7. Miscellaneous. We
like that KTM has embedded their design into the radiator wings, but we
hate the cartoon graphics. Instead, we installed a One Industries’
Technoflex graphics kit (www.oneindustries.com). We cut the tangs off the gas cap with dykes to void its locking capability. We cut the side panels away so that test riders can reach in and grab the subframe to lift the bike on the stand.