1978 Yamaha IT400 Specifications and Specs
Specifications and workshop reference information for the 1978 Yamaha IT400, 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 | Air-cooled, 2-stroke, single-cylinder |
| Displacement | 397 cc |
| Bore × Stroke | 85.0 × 70.0 mm |
| Compression Ratio | 6.8:1 |
| Maximum Power | Approx. 34 hp |
| Maximum Torque | |
| Carburetor | Mikuni | Replacement Options |
| Lubrication | Premix |
| Fuel Mix Ratio | 20:1 | Premix Calculator |
| Ignition | Points |
| Spark Plug | NGK B8ES |
| Spark Plug Gap | 0.6–0.7 mm |
Transmission
| Transmission Type | 5-speed manual |
| Clutch | Wet multi-plate |
| Final Reduction | Chain drive |
Dimensions
| Overall Length | 2,150 mm |
| Overall Width | 860 mm |
| Overall Height | 1,160 mm |
| Wheelbase | 1,430 mm |
| Ground Clearance | 300 mm |
| Fuel Tank Capacity | 9.5 L |
| Bearing Sizes |
Bearing Finder |
Chassis
| Frame Type | Steel single cradle |
| Front Suspension | Telescopic forks | Fork Oil Levels |
| Rear Suspension | Dual shock swingarm |
| Front Suspension Travel | |
| Rear Suspension Travel | |
Brakes & Wheels
400cc Other Specs
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