DIRT BIKE TEST: KTM 250SX–NOV 6
(This test can be found in the December 2002 issue of Dirt Bike Magazine)
KTM?s commitment to racing is obvious. By hiring McGrath and teaming him with the new 250SX, KTM people are chomping at the bit to spit out headlines. They want credibility, they crave results and they?re backing it up with new hardware. So with that in mind, let?s look at the 250SX.
THE SUM OF THE PARTS
Thanks to a new plastic insert and a slightly lower crank weight, the new SX crankshaft is 100 grams lighter than the ?02, a goal to increase the engine response and power development. Also, a shorter connecting rod with identical-to-?02 bore/stroke means that the cylinder is now shorter and lighter. Same goes for the piston; it?s lighter as well. A new digital black box now features a throttle-slide-dependent mapped ignition system. So depending on engine rpm and throttle position, the optimum ignition curve can be achieved for improved throttle response. The Keihin PWK 38AG/TPS carburetor comes with a sensor for the throttle-slide position.
To fit with the compact new engine and the upright cylinder, the new frame of the 250 SX has been shortened by 15mm, which makes for a shorter wheelbase than the ?02. New steering-head gusset plates, various forged components, and a reinforced swingarm bolt contribute to the frame?s enhanced stiffness. As a result of the shorter frame, a 10mm longer swingarm was mounted on the bike.
BITS AND PIECES
THE STUFF OF SUPERCROSS