Restore your Compatible with ATV power and performance with this complete top-end rebuild kit. Fitment Compatible with honda XR400R (1996-2004) TRX400EX Sportrax (1999-2008) and TRX400X (2009, 2012-2014) models, this comprehensive package includes everything needed for a cylinder overhaul. The kit features an 85mm bore cylinder (90.8mm outer diameter) delivering 397cc displacement, along with a matching piston kit, piston ring set, and three essential gaskets. This replacement component is engineered to meet OEM specifications, replacing multiple part numbers including 12100-HN1-A70 and 13011-KCY-670 among others. Perfect for rebuilding worn engines or upgrading performance, this kit provides all necessary components in one package. Each component is manufactured to precise tolerances to ensure proper fit and reliable operation. Installation should be performed by qualified mechanics following proper torque specifications and assembly procedures to guarantee optimal performance.