2011 Kawasaki KX250F
Team Green's newest four-stroke motocrosser has received more than 30 updates to keep ahead of its rapidly changing competition. These aren't minor upgrades, either: Major advances such as digital fuel injection, a revised transmission and the radical new Showa Separate Function Fork (SFF) make this one of the trickest quarter-liter flyers to hit showrooms this season.
The sophisticated DFI fuel-management system that replaces last year's carburetor is identical to that of the bigger-displacement KX450F, only reprogrammed to flow even more fuel and air to keep up with the higher-revving 250's demands. In addition, a modified cylinder and piston bump compression slightly, and a redesigned shift mechanism improves high-rpm response-a complaint on the previous bike.
Streetbikes like the Yamaha YZF-R1 already divide compression and rebound damping functions into separate fork legs. Showa's SFF fork takes this concept one step further by dividing shock absorption and damping into separate legs. There is just one spring, housed in the right leg, while the left leg holds just a damping cartridge. Showa says this design makes the fork easier to set-up and service, and still provides first-rate performance.
Our cohorts from Dirt Rider magazine recently made the trek to Maryland's Budd's Creek Raceway for the KX250F press intro and returned full of praise. The DFI delivers perfectly smooth throttle response, especially at low revs, while the new cylinder and piston maintain the aggressive engine character MX racers demand. They also said you'd never guess from the saddle that this wasn't a conventional fork, with the usual bump resistance and a balanced, planted feel. Check back next issue for the full report.
2011 KTM 250 SX-F
KTM's class-of-one 350 SX-F (reviewed elsewhere in this issue) is the biggest news from the Austrian manufacturer this year, but it's not the only story. Though the company's 450 SX-F is essentially unchanged-even keeping its carburetor-the 250 SX-F four-stroke has been substantially upgraded with fuel injection, new cams, revised valve timing and a redesigned exhaust system to improve flow. Two-strokes also remain alive and well, led by the 250 SX with a newly revised chassis along with intake and exhaust mods that improve power.
2011 Husqvarna WR150
Husky's WR125 enduro is a perennial favorite of off-road riders, renowned for its low weight and agile handling. That winning package gets more potent in 2011 thanks to a displacement increase to 144cc, creating the new, torquier WR150. The chromoly-trellis frame remains unchanged, fitted with a 48mm Kayaba fork, fully adjustable Sachs shock and black Excel wheels to keep the bike tracking true. The bodywork is unchanged as well, made using Husky's uniquely durable IPD (in-mold plastic decoration) graphics. Think of it as the same get-through-anything bike as before, now with a little extra oomph to help you out of tough spots.