2021 Kawasaki Ninja 400 SE Technical Analysis & Specification Breakdown
At the heart of the 2021 Kawasaki Ninja 400 SE sport motorcycle, Kawasaki 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 SE measures 167 kg (368 lbs) wet (curb), translating to a power-to-weight ratio of 0.27 HP/kg (3.73 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 14-liter (3.7 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 2020 to 2021, 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 (3.73 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)
Fuel SystemInjection. DFI® with dual 32mm throttle bodies
Fuel ControlDouble Overhead Cams/Twin Cam (DOHC)
IgnitionTCBI
CoolingLiquid
Transmission
Gearbox6-speed
Final DriveChain (final drive)
ClutchAssist and Slipper Clutch
DrivelineSealed chain
Chassis
Frame TypeTrellius, high- tensile steel
Rake24.7°
Trail91 mm (3.6 inches)
Front SuspensionTelescopic fork
Rear SuspensionHorizontal back-link with adjustable spring preload/5.1 in
Wheelbase1370 mm (53.9 inches)
Ground Clearance140 mm (5.5 inches)
Wheels & Brakes
Front Tyre110/70-17
Rear Tyre150/60-17
Front BrakesSingle disc. Single petal-type disc with 2-piston calipers and optional ABS
Front Brake Ø310 mm (12.2 inches)
Rear BrakesSingle disc. Single petal-type disc with single-piston caliper and optional ABS
Rear Brake Ø220 mm (8.7 inches)
Dimensions & Weight
Weight incl.167.0 kg (368.2 pounds)
Seat Height785 mm (30.9 inches) If adjustable, lowest setting.
Overall Height1125 mm (44.3 inches)
Overall Length1990 mm (78.3 inches)
Overall Width710 mm (28.0 inches)
Fuel Capacity14.00 litres (3.70 US gallons)
Other
StarterElectric
Color OptionsPearl Nightshade Teal/Metallic Spark Black, Passion Red, Metallic Graphite Gray/Metallic Magnetic Dark Gray
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.
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.
