Motorcycle specifications HondaCRF 250 R 2014 Reframing efficiency

the 2013 Honda CRF 250 R was a careful evolution of the previous model, the same one that won both US Supercross Lites titles in 2012. For 2014, the engineers in charge of development chose the path of revolution rather than evolution: they optimized the CRF 250 R by adopting the same philosophy and frame as the CRF 450 R. The engine and PGM-FI fuel injection system have also been upgraded to increase power, torque and throttle control, while weight has been kept down wherever possible.

at the heart of the 2014 CRF 250 R's transformations is the latest-generation aluminum frame inaugurated on the 2013 CRF 450 R model. The new frame's lower center of gravity and reduced inertia further enhance the CRF 250 R's dynamic behavior on the track, as well as in "aerial" sequences. Internal modifications to the Showa 48 mm inverted fork are complemented by the adoption of a new compact rear shock absorber, as well as changes to the Pro-Link and aluminum swingarm design.

as exemplary as ever in terms of availability and ease of operation, the 249 cm3 single-cylinder has benefited from a host of develhRC engineers, in particular on the PGM-FI fuel injection system and on the flow of gases to the intake, cylinder head and exhaust.

in the end, the new CRF 250 R comes even closer to perfection: once again, HRC has delivered a perfectly homogeneous and efficient machine. A superb tool for professionals and amateurs alike.

frame and chassis

for this 6th generation of aluminum frames dedicated to MX, HRC's chassis specialists have set high standards: improved traction front and rear, enhanced grip feel, stability and braking at high speeds, lightness when cornering in all conditions. At just 9.35 kg (for a total weight of 105.7 kg), the CRF 250 R frame is the new benchmark in its class.

in fact, it's a complete redesign: the junction point of the steering column and main spars is now much lower on the column tube, closer to the midpoint than to the top. This change lowers the center of gravity and introduces a kind of "calculated flexibility" into the frame, for the benefit of improved front-end grip and cornering speed. A cradle specific to the CRF 250 R supports the engine.

the steering geometry (27'23° angle, 116.7 mm drag and 1489 mm wheelbase) takes advantage of the frame's newcharacteristics of the frame to offer a more direct connection with the front tire, resulting in a better feel for the available grip and therefore higher cornering speeds. With a lower center of gravity, swaying from side to side is easier, boosting rider confidence and reducing fatigue.

the careful arrangement of equipment around the frame contributes to the centralization of mass, a significant reduction in inertia and a feeling of lightness that emanates from the machine. Electrical components - the electronic control unit, capacitor, regulator and wiring harness - are concentrated around the injector body. The new radiators, lighter and specific to the CRF 250 R, are now located lower down.

in terms of suspension, the upper mount for the Showa shock absorber is now 14.5 mm lower on the frame, while the shock absorber itself - which receives a new mounting - is now lower on the frame.the shock absorber itself - with new spring, compression and rebound settings - is also 14.5 mm shorter. The benefit of mass centralization in this area translates into lower inertia in the axis of the machine, enabling harder braking without compromising stability. Thanks to its greater height at the center and front, the new aluminum swingarm offers greater rigidity, less deformation and improved rear tire propulsion on corner exits.

in 2013, the 48mm Showa inverted fork received new, larger-diameter internal pistons (from 35 to 37mm) for improved low-speed damping characteristics. For 2014, the spring rates have been adapted to the frame's new characteristics. Rebound and compression still offer 16 adjustment possibilities.

the Pro-Link rear suspension benefits from new gear ratios that allow it to travel 375 mm. Fully adjustable, the shock offers 17 rebound settings, while compression can be set to 13 positions (low speeds) and 3.5 turns (high speeds).

the CRF 250 R's new bodywork marks an evolution of the "triangular" styling seen on the 2013 CRF 450 R: the machine is literally built around the rider, with particular attention paid to ergonomics and mass centralization. The radiator scoops, side covers, ultra-light saddle and fuel tank (6.3 liters) all feature a continuity of form that gives the rider considerable freedom of movement and fluidity.

at the same time, the trim's attachment points, with which the rider is likely to come into contact, are highly rigid, allowing him or her to "grip" the bike for better feel and control. Last but not least, the rear mudguard features an integrated lifting point that facilitates handling of the machine in the pits.

the 80/100-21 front and 100/90-19 rear tires help reduce unsprung weight. In terms of braking, the ø 240 mm "petal" front disc and 2-piston caliper are protected by a 2-piece cover, while the rear disc and single-piston caliper are also splash-proof.

engine

during the development cycle, HRC's engine designers focused on a number of points designed to increase the power and availability of the CRF 250 R's engine. The 249 cm3, water-cooled, 4-valve Unicam single-cylinder engine has always impressed users not only with the amount of power available at any rpm, but also with its liveliness at the slightest throttle opening. Improving this omnipresence was one of the objectives.

thanks to a volumetric ratio increased from 13.2 to 1 to 13.5 to 1, as well as a redesigned cylinder head and intake and exhaust ducts, combustion efficiency has been enhanced. Bore and stroke remain unchanged (76.8 x 53.8 mm), as do valve diameters (ø 30.5 mm titanium intake, ø 25 mm steel exhaust). The gearbox, on the other hand, has been redesigned to increase strength. All in all, power and torque gains have been concentrated on the most important rpm range, namely low and mid-range.

as on the CRF450R, the new PGM-FI injection mapping and modified injector angle further enhance performance. Finally, copying that of the 450, the airbox is combined with a dual exhaust system specific to the CRF 250 R, again favoring mass centralization.

Photo credits: Honda