1978 Suzuki RM400C Specifications and Specs
Specifications and workshop reference information for the 1978 Suzuki RM400C, including engine, chassis, service data and setup details.
Note: Specs are compiled from factory data, manuals and owner feedback. Bikes vary — if yours is different, jump into the forum and share it.
General Specifications
| Engine Type | Single-cylinder, two-stroke, air-cooled, reed valve |
| Displacement | 402 cc |
| Bore × Stroke | 80.0 × 80.0 mm |
| Compression Ratio | 6.7:1 |
| Maximum Power | 43 hp @ 6,500 rpm |
| Maximum Torque | 47 Nm @ 6,000 rpm |
| Carburetor | Mikuni VM36SS | Replacement Options |
| Lubrication | Premix |
| Fuel Mix Ratio | 25:1 | Premix Calculator |
| Ignition | Suzuki PEI (CDI) |
| Spark Plug | NGK B8EV |
| Spark Plug Gap | 0.6 – 0.7 mm |
| Air Filter | Foam |
Transmission
| Transmission Type | 5-speed constant mesh |
| Clutch | Wet multi-plate |
| Final Reduction | 13T / 50T |
Dimensions
| Overall Length | 2,140 mm |
| Overall Width | 885 mm |
| Overall Height | 1,225 mm |
| Wheelbase | 1,450 mm |
| Ground Clearance | 290 mm |
| Fuel Tank Capacity | 8.5 L |
| Bearing Sizes |
Bearing Finder |
Chassis
| Frame Type | High-tensile steel semi double cradle |
| Front Suspension | Air/oil telescopic forks | Fork Oil Levels |
| Rear Suspension | Suzuki Tru-Trac twin gas/oil shocks |
| Front Suspension Travel | 249 mm |
| Rear Suspension Travel | 251 mm |
Brakes & Wheels
Service Data
| Chain Type | 520 |
| Chain Links | 110 |
| Front Sprocket | 13T |
| Rear Sprocket | 50T |
400cc Other Specs
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