Built around Honda's allround motorcycle platform, the 1978 Honda CB 400N utilizes a 400 cc (24.4 cu in) air-cooled twin, four-stroke layout. In factory specification, peak output is rated at 42.9 HP (31.3 kW) at 9,500 rpm while maximum torque reaches 33.2 Nm (24.5 lb-ft) at 8,000 rpm. With a specific output of 107.3 HP per liter and a 1,500 rpm working window between peak torque (8,000 rpm) and peak power (9,500 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 CB 400N measures 167 kg (368 lbs) dry, translating to a power-to-weight ratio of 0.26 HP/kg (3.89 kg per horsepower). Rider ergonomics and chassis geometry center around a 795 mm (31.3 in) seat height — offering a neutral standover height that accommodates most average-inseam riders without sacrificing cornering clearance, combined with a 1,390 mm (54.7 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, while factory top speed is listed at 167 km/h (103 mph).
Specific Output
107.3 HP/L
Power-to-Weight
0.26 HP/kg (3.89 kg/HP)
Power Band Window
8,000–9,500 rpm
Standover Height
795 mm (31.3 in)
Engine
Displacement400.0 ccm (24.41 cubic inches)
Engine TypeTwin, four-stroke
Power42.9 HP (31.3 kW)) @ 9500 RPM
Torque33.2 Nm (3.4 kgf-m or 24.5 ft.lbs) @ 8000 RPM
Compression9.4:1
Bore x Stroke70.5 x 50.6 mm (2.8 x 2.0 inches)
Fuel SystemCarburettor. Keihin 32mm
IgnitionElectronic
CoolingAir
Performance
Top Speed166.5 km/h (103.4 mph)
Chassis
Front SuspensionTelescopic fork
Rear SuspensionSwingarm Twin Shock
Wheelbase1390 mm (54.7 inches)
Wheels & Brakes
Front Tyre3.60-19
Rear Tyre4.10-18
Front BrakesDouble disc
Rear BrakesExpanding brake (drum brake)
Dimensions & Weight
Dry Weight167.0 kg (368.2 pounds)
Power/Weight0.2569 HP/kg
Seat Height795 mm (31.3 inches) If adjustable, lowest setting.
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.
