The Yamaha RD400F (1978-79) is a two-stroke motorcycle with a parallel twin-cylinder engine that has a capacity of 398cc. It features air cooling with a compression ratio of 6.2:1 and uses Autolube lubrication with reed-valve torque induction. Its ignition is a CDI and starting is via kick. It can produce a maximum power of 44 hp / 32.3 kW @ 7500 rpm and max torque of 41.1 Nm / 4.2 kgf-m @ 7000 rpm. The clutch is wet multiplate with six-speed transmission and chain final drive. The front suspension is a telescopic fork, while the rear suspension has a swing arm with dual shocks. The front and rear brakes have single 267mm discs, with front and rear tires of 3.00S-18 and 3.50S-18, respectively. The dimensions of the bike are length 1995 mm / 78.5 in, width 760 mm / 3.0 in, and height 1060 mm / 41.7 in. It has a wheelbase of 1320 mm / 51.9 in, seat height of 800 mm / 31.4 in, ground clearance of 150 mm / 5.9 in, dry weight of 165.5 kg / 364.8 lbs, and a fuel capacity of 16.5 Litres / 4.3 US gal. Its average consumption is 43 mpg, with a standing 1/4 mile of 14.1 sec / 90.1 mph 145 km/h and a top speed of 106.8 mph 172 km/h.
Technical specifications:
Make Model: Yamaha RD 400
| Year | 1978 – 79 |
|---|---|
| Engine | Two stroke, parallel twin cylinder, reed-valve torque induction |
| Capacity | 398 cc / 24.2 cu-in |
| Bore x Stroke | 64 62 mm |
| Cooling System | Air cooled |
| Compression Ratio | 6.2:1 |
| Lubrication | Autolube |
| Induction | 2x 28mm Mikuni carburetors |
| Ignition | CDI |
| Starting | Kick |
| Max Power | 44 hp / 32.3 kW @ 7500 rpm |
| Max Torque | 41.1 Nm / 4.2 kgf-m @ 7000 rpm |
| Clutch | Wet multiplate |
| Transmission | 6 Speed |
| Final Drive | Chain |
| Front Suspension | Telescopic forks |
| Rear Suspension | Swing arm, dual shocks |
| Front Brakes | Single 267mm disc |
| Rear Brakes | Single 267mm disc |
| Front Tyre | 3.00S-18 |
| Rear Tyre | 3.50S-18 |
| Dimensions | Length 1995 mm / 78.5 in Width 760 mm / 3.0 in Height 1060 mm / 41.7 in |
| Wheelbase | 1320 mm / 51.9 in |
| Seat Height | 800 mm / 31.4 in |
| Ground Clearance | 150 mm / 5.9 in |
| Dry Weight | 165.5 kg / 364.8 lbs |
| Wet Weight | 171 kg / 376 lbs |
| Fuel Capacity | 16.5 Litres / 4.3 US gal |
| Consumption Average | 43 mpg |
| Standing 1/4 Mile | 14.1 sec / 90.1 mph 145 km/h |
| Top Speed | 106.8 mph 172 km/h |
