| MODEL | YAMAHA IT 400 1979 |
| Year | 1979 |
| Engine Type | Two stroke, single cylinder, reed valve |
| Displacement / Capacity | 396 cc / 24.1 cu in |
| Bore X Stroke | 82 x 75 mm |
| Compression Ratio | 7.4:1 |
| Cooling System | — |
| Max Power | 27 kW / 36.7 hp @ 6500 rpm |
| Max Torque | 40 Nm / 29.6 lb-ft @ 6500 rpm |
| Ignition | CDI |
| Induction | Mikuni VM38SS carburettor |
| Start System | — |
| TRANSMISSION SPECS | |
| Lubrication | — |
| Gear Box | 5 Speed |
| Clutch | Wet, multi-plate |
| Final Drive | Chain |
| CHASSIS SPECS | |
| Frame | — |
| Front Suspension | Telescopic adjustable forks, 230 mm / 9 in travel |
| Rear Suspension | Monoshock, adjustable spring preload and rebound damping, 205 mm / 8 in travel |
| Front Brakes | Drum |
| Rear Brakes | Drum |
| DIMENSION SPECS | |
| Overall Length | — |
| Overall Width | — |
| Overall Height | — |
| Seat Height | 889 mm / 35 in |
| Wheelbase | 1420 mm / 55.9 in |
| Ground Clearance | 260 mm / 10.25 in |
| Dry Weight | 115 kg / 253.5 lbs |
| Wet Weight | 121.5 kg / 268 lbs |
| WHEEL SPECS | |
| Front Tyre | 3.00 x 21 |
| Rear Tyre | 4.50 x 18 |
| FUEL SYSTEM | |
| Fuel Capacity | 12 Litres / 3.2 US gal |
| Fuel Consumption | — |
| Top Speed | — |
For 1979 the IT 400 was reworked with a shorter-bore, longer-stroke engine that made more torque lower in the rev range, plus more suspension travel and a lower seat. Brakes were still drums front and rear.
