NGK BR9EIXequivalent & cross reference

The NGK BR9EIX spark plug is directly equivalent to DENSO W27ESR-U and DENSO IW27, confirmed by shared applications in both manufacturers' official catalogues.

Equivalents

Part	Shared applications	Agreement
DENSO W27ESR-U	14	50%
DENSO IW27	23	82%

Verified fitments for the NGK BR9EIX

Aprilia RS 50 (1999–2005)
KTM EXC 125 (1995–2003)
KTM EXC 200 (2004–2008)
Yamaha DT 125 R (1988–2003)
Yamaha TDR 250 (1988–1992)

Equivalence confirmed by 3 independent sources, last verified 22 July 2026. Always confirm fitment against your owner's manual.