Skip to content
JAPANESE
MOTORCYCLE ARCHIVE
EN/JA
Yamaha SR400 at the 2009 Tokyo Motor Show

YAMAHA

SR400

Yamaha SR400

Manufacturer
YAMAHA
Model
SR400
Year
1978
Type
Standard
Origin
Japan
Photo: TTTNIS / Public domain

01 — Overview

Since its debut in March 1978, the SR400 held its following with a simple, largely unchanged style and the pulse of its kick-started, air-cooled single. For the Japanese market the line concluded with the Final Edition Limited of 2021. Specifications listed are those of the 2021 Final Edition Limited.

MAKER
YAMAHA
PRODUCTION
1978–2021

02 — Historical Context

HISTORICAL CONTEXT

It appeared in 1978 alongside the SR500, which applied know-how from the XT500 to a road bike; according to Yamaha, the SR400, the displacement variant suited to the Japanese licence system, remained popular for some 40 years.

1970s — Large multi-cylinder machines and potent two-strokes established Japanese big bikes on the world's roads.

03 — Engine

ENGINE

Single

One cylinder: light, simple and characterful. Found everywhere from commuters to off-road machines and classics. Intake, compression, power, exhaust — the cycle behind today's combustion motorcycles.General description of the layout

Engine layoutSingle[1]
CycleFour-stroke[1]
Displacement399 cc[1]
CoolingAir-cooled[1]
ValvetrainSOHC, 2-valve[1]
Max. power18 kW / 6,500 rpm[1]
Max. power24 PS / 6,500 rpm[1]
Max. torque28 N·m / 3,000 rpm[1]
Max. torque2.9 kgf·m / 3,000 rpm[1]

04 — Specifications

TECHNICAL SPECIFICATIONS

Every figure is sourced. Unverified values are not published.

Production1978 – 2021[1]
Engine layoutSingle[1]
CycleFour-stroke[1]
Displacement399 cc[1]
CoolingAir-cooled[1]
ValvetrainSOHC, 2-valve[1]
Max. power18 kW / 6,500 rpm[1]
Max. power24 PS / 6,500 rpm[1]
Max. torque28 N·m / 3,000 rpm[1]
Max. torque2.9 kgf·m / 3,000 rpm[1]

05 — Generations

GENERATION HISTORY

19732026

2021 Final Edition Limited (spec shown)1978–2021

Generations, model years and market variants (Model → Generation → Variant) are added as they are verified.

06 — Cultural Context

CULTURAL CONTEXT

07 — On Film

ON FILM

Quoted from official channels

08 — Gallery

GALLERY

RELATED MOTORCYCLES

09

Yamaha YA-1 on display at Yamaha Communication Plaza

YAMAHA

Yamaha YA-1

1955
Standard

1970 Yamaha XS-1 on display at Yamaha Communication Plaza

YAMAHA

Yamaha XS-1

1970
Standard

1968 Yamaha DT-1 on display at Yamaha Communication Plaza

YAMAHA

Yamaha DT-1

1968
Trail

Front-left view of a 1971 Suzuki GT750 in Candy Bright Red at Suzuki Plaza

SUZUKI

Suzuki GT750

1971
Standard

10 — Sources

SOURCES

  1. [1]2021 SR400 Final Edition Limited - Communication Plaza CollectionYamaha Motor Co., Ltd. · museum · accessed 2026-09-26
  2. [2]Yamaha Motor History - Product History (Motorcycles / Commuter Vehicles)Yamaha Motor Co., Ltd. · manufacturer · accessed 2026-09-26
  3. [3]ヤマハ発動機 製品ヒストリーヤマハ発動機株式会社 · manufacturer · accessed 2026-09-26

11 — Image Credits

PHOTO CREDITS

  • Creator
    TTTNIS
    License
    Public domain · Wikimedia Commons
    TTTNIS, Public domain, via Wikimedia Commons