The Yamaha 4H7818400100 Brush Holder Assembly is an original equipment manufacturer (OEM) part designed for the starter motor of a wide range of Yamaha motorcycles and ATVs. This critical electrical component ensures proper contact for the starter motor brushes, facilitating reliable engine starting. It is a direct replacement for the superseded part number 4H7818400000, ensuring perfect fit and function for compatible models, including popular series like XS, XJ, XV, and YFM.