Does the DENSO W22EPR-U fit the Yamaha XS 400 (1979–1979)?
Yes — the DENSO W22EPR-U is a correct fitment for the Yamaha XS 400 (1979–1979).
Last verified: 22 July 2026 against 2 independent sources (Cross-brand plug correspondence (NGK + Denso catalogues), Denso Motorcycle Spark Plug Catalogue (official PDF)).
Brakes are safety-critical. Always confirm fitment against your owner's manual before purchase and installation.