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MotoLibrary Score
46/100Balanced
Power/Weight
0.41 hp/kg
Top Speed
148 km/h
Torque
5 Nm
Engine
402 ccm
Technical Overview
1978 Suzuki RM 400 C Technical Analysis & Specification Breakdown
Positioned in Suzuki's cross - motocross motorcycle lineup, the 1978 Suzuki RM 400 C utilizes a 402 cc (24.5 cu in) air-cooled single cylinder, two-stroke layout. In factory specification, peak output is rated at 43 HP (31.4 kW) at 6,500 rpm while maximum torque reaches 4.8 Nm (3.6 lb-ft) at 6,000 rpm, transferring power to the rear wheel through a 5-speed gearbox and chain final drive. With a specific output of 107 HP per liter and a 500 rpm working window between peak torque (6,000 rpm) and peak power (6,500 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 RM 400 C measures 105 kg (231 lbs) dry, translating to a power-to-weight ratio of 0.41 HP/kg (2.44 kg per horsepower). Rider ergonomics and chassis geometry center around a 1,450 mm (57.1 in) wheelbase engineered for balanced agility and highway composure. The 8.5-liter (2.2 US gal) fuel tank supports practical everyday commuting and weekend road stints, while factory top speed is listed at 148 km/h (92 mph).
Specific Output
107 HP/L
Power-to-Weight
0.41 HP/kg (2.44 kg/HP)
Power Band Window
6,000–6,500 rpm
Engine
Displacement402.0 ccm (24.53 cubic inches)
Engine TypeSingle cylinder, two-stroke
Engine DetailsSingle cylinder, two-stroke
Power43.0 HP (31.4 kW)) @ 6500 RPM
Torque4.8 Nm (0.5 kgf-m or 3.6 ft.lbs) @ 6000 RPM
Compression6.7:1
Bore x Stroke80.0 x 80.0 mm (3.1 x 3.1 inches)
Fuel SystemCarburettor. Mikuni VM36SS
IgnitionSuzuki PEI
CoolingAir
Max RPM6700
Transmission
Gearbox5-speed
Final DriveChain (final drive)
ClutchWet Multiplate Type
Performance
Top Speed148.0 km/h (92.0 mph)
ExhaustExpansion Chamber with silencer
Chassis
Frame TypeHigh Tension Steel Pipe Single Downtube Semi Double Cradle
Front SuspensionTelescopic coil spring air oil infinately adjustable damping
Front Travel249 mm (9.8 inches)
Rear SuspensionSuzuki Tru-Trac Twin shocks gas/oil damping aluminium swinging arm
Rear Travel244 mm (9.6 inches)
Wheelbase1450 mm (57.1 inches)
Ground Clearance290 mm (11.4 inches)
Wheels & Brakes
Front BrakesExpanding brake (drum brake)
Rear BrakesExpanding brake (drum brake). full floating rear brake design
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.
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.
