Yamaha RD 400 Specs (Top Speed | Horsepower | Weight)

The Yamaha RD 400 motorcycle specifications include a 399 cc (24.35 cu in) engine, a 6-speed gearbox, and a listed weight of 175 kg (385.8 lb).

Key specifications

1978-1979Model years
399 ccDisplacement
175 kgWet weight
16.5 LFuel tank
Model years covered
19781979

Year-specific specification changes

No material specification changes from the 1978 baseline were found in the available data.

How the Yamaha RD 400 compares

This compares the motorcycle with all Yamaha models in this specifications database. The blue marker is this model and the grey line is the Yamaha database average.

Displacement399 cc
Low 49 ccAverage 550 ccHigh 1,852 cc

About 27% lower than the Yamaha database average. Around the 48th percentile across Yamaha models.

Wet weight175 kg
Low 72.1 kgAverage 186.3 kgHigh 348.7 kg

About 6% lighter than the Yamaha database average. Around the 47th percentile across Yamaha models.

Fuel capacity16.5 L
Low 4 LAverage 13 LHigh 24 L

About 27% larger than the Yamaha database average. Around the 67th percentile across Yamaha models.

This model Yamaha database average

Yamaha database percentile rankings

Percentiles show where this motorcycle sits across the Yamaha specifications database. They are descriptive database rankings, not performance ratings.

Displacement48th

399 cc — larger displacement than about 48% of Yamaha models.

Wet weight47th

175 kg — heavier than about 47% of Yamaha models, or lighter than about 53%.

Fuel capacity67th

16.5 L — larger than about 67% of Yamaha fuel tanks in this database.

Mechanical overview

Engine layout snapshot

Twin, two-stroke • 399 cc • Air cooled
Chassis snapshot

6-speed • Chain (final drive) • 3.00-18 front / 3.50-18 rear

Additional useful specifications

Front tire size 3.00-18
Rear tire size 3.50-18
Bore/stroke ratio 1.03:1 (Oversquare)

Model information

Category Classic

Engine specifications

Engine type Twin, two-stroke
Displacement 399 cc (24.35 cu in)
Bore × stroke 64.0 x 62 mm (2.5 x 2.4 inches)
Compression ratio 6.0:1
Cooling system Air
Fuel control Membrane

Transmission and drivetrain

Gearbox 6-speed
Final drive Chain (final drive)

Brakes, wheels and tires

Front brakes Single disc
Rear brakes Single disc
Front tire 3.00-18
Rear tire 3.50-18

Dimensions and weight

Wet weight 175 kg (385.8 lb)

Fuel and emissions

Fuel capacity 16.50 L (4.36 US gal)

Performance

Top speed 175.0 km/h (108.7 mph)

Disclaimer: Specifications may vary by market, trim, production date and optional equipment, and scraped or historical data can contain errors. Comparison and percentile values are calculated from Yamaha models in this specifications database. Always double-check important specifications against the motorcycle owner’s/service manual and official Yamaha information before relying on them. Visit the official Yamaha website.