YZ400F
Category: Motocross
Manufacturer: Yamaha
Hits: 794
| Year | 1979 |
| Engine Class | 400 |
| VIN Prefix | 2X5 |
| Known VIN Range (Vehicle ID Numbers) | 000101 - |
| Tank Color(s) | Competition Yellow |
| Country of Sale | USA |
| Bore (MM) | 82 |
| Stroke (MM) | 75 |
| Displacement (CC) | 397 |
| Compression Ratio (to 1) | 7.4 |
| BHP @ RPM | 39.9 @ 7,000 |
| Torque (kgm) @ RPM | 4.02 @ 7,000 |
| Autolube Injection? | No |
| Engine Cooling | Air |
| Carburetor Model | VM38SS |
| Ignition Type | CDI (Electronic) |
| Ignition Timing MM (BTDC) | 3.1 |
| Primary Drive Gearing | 2.61 |
| Final Drive Gearing (Sprockets) | 50/14 |
| Box Gearing First | 2.38 |
| Box Gearing Second | 1.75 |
| Box Gearing Third | 1.32 |
| Box Gearing Fourth | 1.05 |
| Box Gearing Fifth | 0.83 |
| Fuel Capacity (L) | 7.6 |
| Gearbox Oil Capacity | 0.85 |
| Fork Oil Capacity (CC/Fork Leg) | 364 |
| Front Tire (stock) | 3.00 x 21 |
| Rear Tire (stock) | 5.10 X 18 |
| Front Brake Type | Drum |
| Rear Brake Type | Drum |
| Rear Suspension | Mono Shock |
| Front Suspension Travel (mm) | 270 |
| Rear Suspension Travel (mm) | 265 |
| Rake (degrees) | 29.5 |
| Trail (mm) | 128 |
| Overall Width (mm) | 935 |
| Ground Clearance (mm) | 320 |
| Wheelbase (mm) | 1,450 |
| Dry Weight (kg) | 102 |