Engineered by Kawasaki for the sport motorcycle segment, the 2021 Kawasaki Ninja 400 KRT features a 399 cc (24.4 cu in) liquid-cooled twin, four-stroke configuration. In factory specification, peak output is rated at 44.8 HP (32.7 kW) at 10,000 rpm while maximum torque reaches 38 Nm (28 lb-ft) at 8,000 rpm, transferring power to the rear wheel through a 6-speed gearbox and chain final drive. With a specific output of 112.3 HP per liter and a 2,000 rpm working window between peak torque (8,000 rpm) and peak power (10,000 rpm), the engine character is reflecting a performance-oriented street tune that balances strong mid-range pull with an energetic top-end rush.
On the scales, the Ninja 400 KRT measures 165 kg (364 lbs) dry, translating to a power-to-weight ratio of 0.27 HP/kg (3.68 kg per horsepower). Rider ergonomics and chassis geometry center around a 785 mm (30.9 in) seat height — offering a neutral standover height that accommodates most average-inseam riders without sacrificing cornering clearance, combined with a 1,370 mm (53.9 in) wheelbase engineered for quick, flickable steering geometry. The 3.7-liter (1 US gal) fuel tank supports practical everyday commuting and weekend road stints.
Within MotoLibrary's Kawasaki archive, this model family spans 2 indexed model years from 2021 to 2023, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.
Specific Output
112.3 HP/L
Power-to-Weight
0.27 HP/kg (3.68 kg/HP)
Power Band Window
8,000–10,000 rpm
Standover Height
785 mm (30.9 in)
Engine
Displacement399.0 ccm (24.35 cubic inches)
Engine TypeTwin, four-stroke
Power44.8 HP (32.7 kW)) @ 10000 RPM
Torque38.0 Nm (3.9 kgf-m or 28.0 ft.lbs) @ 8000 RPM
Compression11.5:1
Bore x Stroke70.0 x 51.8 mm (2.8 x 2.0 inches)
Valves/Cylinder4
Fuel SystemInjection. 32 mm x 2
Fuel ControlDouble Overhead Cams/Twin Cam (DOHC)
IgnitionTCBI w/digital advance
LubricationForced lubrication, wet sump
CoolingLiquid
Transmission
Gearbox6-speed
Final DriveChain (final drive)
ClutchAssist and Slipper Clutch
DrivelineSealed chain
Chain Size520
Chassis
Frame TypeTrellis, high-tensile steel
Rake24.7°
Trail91 mm (3.6 inches)
Front Suspension41mm hydraulic telescopic fork
Front Travel119 mm (4.7 inches)
Rear SuspensionHorizontal back-link with adjustable spring preload
Rear Travel130 mm (5.1 inches)
Wheelbase1370 mm (53.9 inches)
Ground Clearance140 mm (5.5 inches)
Wheels & Brakes
Front Tyre110/70-17
Rear Tyre150/70-17
Front Tire Pressure2.0 bar (29 psi)
Rear Tire Pressure2.2 bar (32 psi)
Front BrakesSingle disc. Petal-type disc with 2-piston calipers. Optional ABS.
Front Brake Ø310 mm (12.2 inches)
Rear BrakesSingle disc. Petal-type disc with single-piston caliper. Optional ABS.
Rear Brake Ø220 mm (8.7 inches)
WheelsCast aluminium alloy rims
Dimensions & Weight
Dry Weight165.0 kg (363.8 pounds)
Power/Weight0.2715 HP/kg
Seat Height785 mm (30.9 inches) If adjustable, lowest setting.
Overall Height1120 mm (44.1 inches)
Overall Length1990 mm (78.3 inches)
Overall Width710 mm (28.0 inches)
Fuel Capacity3.70 litres (0.98 US gallons)
Oil Capacity1.80 litres (1.90 US quarts)
Service & Fluids
Engine OilSAE 10W-40 / 10W-50 Synthetic 4T (API SN / JASO MA2)
Use this page to compare this motorcycle by its real specifications, not only by model name. Focus on the details that affect fit, comfort, handling, range and ownership.
Power
Compare engine output with similar motorcycles if acceleration, highway use or two-up riding matters.
Torque
Torque is useful for judging real-world pull, especially for touring, commuting and loaded riding.
Seat Height
Check the seat height against your inseam and riding posture before choosing a motorcycle.
Weight
Compare weight carefully because it affects low-speed handling, parking and confidence.
Fuel Capacity
Fuel capacity helps estimate touring range and how often you may need to stop.
Brakes
Brake setup is worth comparing if you ride in traffic, mountains or with a passenger.
Suspension
Suspension details can matter for comfort, road feel and long-distance riding.
Transmission
Transmission and final drive affect maintenance, smoothness and everyday usability.
