Carburetor features a throttle position sensor (TPS) and an accelerator pump that help maintain linear throttle response throughout the rpm range.
Electric starter drives the clutch side of the crankshaft to provide superior lubrication to starter gears, and produce a narrow engine with a short, strong crankshaft.
Lightweight, compact, internal auto decompressor system provides superb cold-starting and hot-starting operation.
37 mm Keihin FCR-type carburetor features four rollers on the flat slide, resulting in very light throttle effort, smooth operation, crisp throttle response and excellent rideability.
18-inch rear wheel features the same lightweight rear hub and HRC works-type lightweight aluminum spoke nipples as used on the CRF250R.
Rear shock damper piston diameter is 50 mm for consistent performance under demanding riding conditions.
Twin-sump lubrication system separates the oil supply for the crankshaft, piston and valve train from the clutch and transmission. This ensures a cool supply of oil to the clutch, eliminates clutch and transmission material contamination of the engine oil, reduces the amount of circulating oil, and permits the use of a smaller oil pump.
Lightweight 47 mm inverted Showa twin-chamber cartridge fork with aluminum dampers is derived from the CRF250R and features settings unique to the CRF250X. The fork offers 315 mm (12.4 inches) of travel, and 16-position rebound and 16-position compression damping adjustability. The inner surface of the front fork outer-tubes receives the same honing treatment as works bikes for low-friction operation.
HRC works-type rear brake system integrates the rear master cylinder and fluid reservoir, eliminating the need for a remote master cylinder reservoir and hose assembly.
Pro-Link single-shock rear suspension system features a fully adjustable Showa rear damper and 313 mm (12.3 inches) of wheel travel, separate low-speed (13 positions) and high-speed (3.5 turns) compression damping adjusters, and 17-position rebound damping adjustment.
Compact dual-piston front brake caliper, anodized aluminum brake pistons and lightweight front brake disc minimize unsprung weight for improved turning and handling.
Final Drive : #520 T-ring-sealed chain; 14T/53T
240 mm wave-style front and rear brake discs reduce unsprung weight.
Wide-ratio five-speed transmission
Powerful 4-stroke 249 cc liquid-cooled four-valve Unicam engine is designed to produce power across a wide rpm band for easy-to-control operation. Unicam valve train provides the light weight of a compact single-cam design and the optimum combustion chamber shape for maximum power at all engine rpm.
Unicam valve train features a carburized single camshaft that directly actuates two 31 mm titanium intake valves. The camshaft exhaust lobe actuates two 26 mm steel exhaust valves via a forked, low-friction, roller rocker-arm. Lightweight titanium intake valves permit use of smaller valve springs, reducing overall engine height. Vertically split crankcases feature a built-in oil pump, reducing weight compared to a conventional design.
Forged 12.9:1-compression slipper piston is lighter than a conventional design, revving quickly while maintaining excellent cylinder sealing and high-rpm power.
Double-carburized connecting rod utilizes a big-end needle bearing for maximum high-rpm performance and durability. Nikasil cylinder lining is lightweight and provides cooler and quieter operation for extended engine life.
Semi-double-cradle twin-spar aluminum frame features a single large-diameter tapered downtube. Two rugged box-section rails attach to the base of the downtube and support the engine. A forged aluminum steering head provides a compact and extremely durable mount for the frame spars and engine downtube. In addition, tall swingarm pivot plates and narrow frame spars create a narrow overall frame cross-section for superb rider comfort and manoeuvrability. Swingarm features a dual-axis, double-taper design with a large cast-aluminum cross-member.
Front wheel features large-diameter front axle and wide wheel-bearing span for excellent rigidity. Rear-axle diameter of 25 mm and large-diameter bearings provide optimum rigidity to withstand torturous off-road conditions.