About the Yamaha XS400
Separate the early XS400 and Special applications from the later Seca before ordering.
The XS400 name spans more than one Yamaha twin. The 1982 Seca introduced a different DOHC engine and monoshock chassis. An XS400 badge and an approximate year therefore cannot identify the engine gasket, carburetor or brake parts fitted to every version.
Use this family page to choose a model, then move to the repair. The early overhaul gasket set lists XS400 1977–1981 and XS400S 1980–1982. The separate Athena set lists XS400R 1982–1984 and later XS400 applications. Those are different engine-service products, with their own fitment lines.
Choose the correct model and applicationYamaha XS400 model and repair differences
Early XS400
Carburetor and engine service
The carburetor-kit example covers XS400 1977–1979. The early overhaul gasket set extends to 1981; that later gasket coverage does not extend the carb kit.
XS400S
Special applications
The S collection has its own brake and clutch applications. Keep XS400S in the selection rather than assuming an unsuffixed XS400 listing covers the same parts.
XS400R
Seca engine and chassis
Use the R collection for the later Seca examples, including its separate engine gasket set and front master-cylinder kit. A shared dust seal does not establish complete fork interchange.
Frame, engine and fitted componentsYamaha XS400 identification checklist
- Record both frame and engine identity; a replacement engine can require a different gasket family.
- Check the complete model designation and market against the correct Yamaha manual. Do not treat an S or R suffix as optional.
- Identify the carburetor body and fuel-valve arrangement before selecting a kit or float needle.
- Record front and rear brake type separately, then compare the actual caliper or drum and fork-seal dimensions.
Contact PartsNMore with your model, year and clear component photos.