New Kawasaki Ninja 250R Engine

The 249 cc liquid-cooled, DOHC parallel-twin engine was designed for rider-friendly response, the Ninja 250R's engine was tuned to deliver smooth, step-free power. Riders who use the full range of the engine will be pleasantly surprised by the ample high-rpm performance. To enable riders to enjoy this model for a number of years, many of the engine features contribute to durability and reliability.



Carburettor
Settings for the twin Keihin CVK30 carburettors were idealised for good power feel with low fuel consumption

Cylinder Head
Idealised intake and exhaust ports contribute to good off-idle response and smooth power delivery.

Direct valve actuation ensures reliable high-rpm operability. Valves with thin heads and stems reduce reciprocating weight. Valve timing and lift weredesigned for low- and mid-range torque.

Piston / Cylinder
Pistons feature reinforced heads and strengthening in the pin boss areafor increased durability. (Longitudinally) thick piston rings helpminimize oil consumption. Combustion chamber design optimizes thesquish area, maximizing combustion efficiency and thereby reducingemissions.

Exhaust System
The 2-into-1 exhaust system contributes to low- and mid-range torqueand helps achieve the Ninja 250R's smooth, step-free power curve.

Slightly upswept silencer underwent extensive testing to determine chambe rdivision ratios and connecting pipe length and diameter. The result is reduced noise with minimum power loss.

Dual catalyzers, one in the collector pipe, one in the silencer, ensure strict emissions are met. Locating the first catalyzer as close to the exhaust ports aspossible maximizes its efficiency. Using two catalyzers enables powerloss to be minimized. (Carburetted models features pipe catalyzers; fuel injected models use honeycomb catalyzers.)


Cooling
Latest generation Denso radiator offers superior cooling performance while minimising space and weight.

Noise-reducing ring-fan is operated by quiet-running print motor that also contributes to space savings.

Fins on the lower side of the crankcase further contribute to engine cooling.

Mechanical Noise Reduction
Cam chain tensioner like that used on our KX450F motocrosser featuresan automatic adjuster with threads and springs. The systemautomatically eliminates mechanical noise caused by a loose cam chain,reducing power-robbing friction loss.

The air cleaner features acomplex construction with reinforcing ribs that help eliminatereverberation, for reduced intake noise. Extensive testing to determinethe diameter, length and thickness of the intake ducting ensuresefficient filling.