Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/126801
For most riders, the '85 KTM 250 MX is raceready right out of the crate, but for the Intermediate and Pro-level riders, the KTM needs some suspension work - mostly in the rear. Since the KTM comes stock with White Power suspension components, we let the folks at White Bros do the fine tuning - they specialize in White Power suspension products. The White Power 4050 inverted fork needed lillIe allention. The oil level was raised using 5w oil. It was set 160mm with the forks compressed. In development is a new damping piston that will increase com pressiondamping making the fork more progressive and should eliminate any harsh spots throughout the wheel travel. The piston should be available in a few weeks. The shock was completely torn down and rebuilt. The oil was changed to White Bros suspension fluid, which is between 5w and 4w. For better high-speed compression damping, a new piston was used with smaller holes, while flex valving was softened. This .is designed to make the shock more progressive with less bolloming. To eliminate too much springback from bottoming, more mid- to high-speed rebound damping was added by reshaping the valve pack; in other words, res tacking the damping washers. The KTM comes stock with the preload selling at 20 to 23mm. White Bros reduced this to 14 to 17mm, depending on the rider's weight. Once on the track, the KTM's suspension was noticeably beuer, but most improved was in the rear. Over large to mid-size bumps at speed, the KTM is much more stable. No longer does it bOllom harshly in the rear, while swapping is non-existent. Up front, the fork absorbed the large bumps, making the ride smoother, while bOlloming is rarely noticed. Over smaller bumps. both front and rear suspensions are a tad on lhe _ stiff side. When exiling a turn under full power when lhere are a 101 of mall bumps, the ride get a lillie rough. One problem encoumered wilh the stock suspension happened when braking at speed over small braking bumps. The front shook, making the the rider hold on tight to the handlebars. The White Bros-tuned fork helped out, but didn't eliminate the problem. (Left) The White Power inverted fork didn't need too much attention. (Right) The damping piston was replaced in the shock, while valYing, preload and oil were also changed. The investment is worthwhile. The White Bros-modified KTM improved handling over large bumps 100%; exactly where the KTM needed the most help. This combined with its awesome horsepower - will make the KTM a serious contender for the Intermediate/Pro-level rider. We definitely recommend the White Bros~ touch for the KTM. It costs approximately $85 to rebuild the shock; if a different spring is needed, they retail for $69.95. Basic fork rebuilt is approximately $45. For more information, contact White Bros at 11750 Seaboard Circle, Stanton, CA 90680. Phone 714/895-1991. 29