This starter solenoid relay is compatible with YZF-R1 models from 1999, 2000, 2002–2006, and 2009, as well as YZF-R6 models from 1995–2007.It is designed as a replacement electrical component to restore starting functionality and maintain factory-intended function.Constructed from metal, plastic, and aluminum, this part matches OEM specifications for fitment.Referenced OEM part numbers are provided for compatibility verification only: 4YR-81940-00-00, 4YR-81940-02-00, 4SV-81940-12-00, 4SV-81940-00-00, 4DN-81940-12-00, 5JW-81940-00-00, 5JW-81940-02-00, 4BH-81940-02-00, 2C0-81940-00-00, 4DN-81940-11-00, 4XE-81940-12-00, 1D0-81940-02-00, 5EK-81940-00-00, 5EK-81940-02-00, 5TJ-81940-10-00, 5TJ-81940-12-00, 4BH-81940-00-00.