FRIDAY’S USED MOTOCROSS BIKE GUIDE: HOW TO SETUP YOUR 2009 KTM 250SXF:

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

    Main: 175
    Pilot: 40
    Needle: OBEKP
    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 The stock Bridgestone M59/M70 tire combination is good, but the tires are rather outdated.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.

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