Heir to the 450R
, the 2009 Honda CRF250R
gets significant upgrades to the brakes, engine and tires. A direct beneficiary of the technologies and main components used by its larger sister, this new model will undoubtedly wreak even more havoc on the trails next summer.
Not so long ago, 2-stroke dirt bikes could easily trump their 4-stroke counterparts and their heavy, anemic engines. Now, however, modern 4-stroke powerplants like Honda's Unicam deliver more power, more torque and higher revs than comparable 2-stroke mills. Since 2002, the Japanese manufacturer has played a decisive role in the advancement of 4-stroke engines; the high-performance, single-cylinder Unicam is currently North America's best seller in its class. Compact yet powerful
Smaller than a DOHC engine, the Unicam gets a new cylinder head for 2009, not to mention new valves and a revised exhaust manifold designed to increase torque under 8,000 rpm and, as a result, allow faster accelerations on the fly. Feeding the engine is a 40-mm, FCR-type carburetor. Honda engineers reprogrammed the ECU for higher-revving operation; the redline now starts at 13,500 rpm and helps deliver increased power. Impressive!
The transmission of the Honda CRF250R has been entirely revised to offer a smoother yet sharper gear selection. The clutch drum now features four notches (instead of three), eight plates (instead of six) and softer springs for reduced friction during gear shifts, making shifting easier and more accurate. Likewise, engineers reworked and strengthened the key components of the gearbox (drum, shafts, gears and selector forks) to improve shifting. Lightweight and efficient
The new CRF250R has gone through a major weight loss program in order to enhance overall performance. Modifications include:
- new brake discs for a 65-gram saving;
- new, lighter ventilated disc guards;
- smaller wheel hubs and axle in the back for a 38-gram saving;
- new, lighter aluminum handlebar with 3-mm longer hand grips for improved control.
|Feeding the engine is a 40-mm, FCR-type carburetor.|