RFX start button / kill switch YFZ450R 09-26 The RFX Race Series start button and kill switch for Yamaha YFZ450R (2009-2026) is an OEM-style replacement designed to replace the original switch assembly. It comes with the same connectors, mounting points and cable length as the original part for easy installation. Designed as a reliable replacement component, it restores proper engine start and stop functions while maintaining original compatibility with the quad’s electrical system.