Piston Ring Kit Fit For Honda XR400 TRX400EX Big Bore 85mm Cylinder Gasket Set 1997 2004 1999 2007 XR400 XR400R 1997-2004 TRX400 TRX400EX 1999-2007;complete 85mm big bore upgrade replacement assembly Designed for 85mm cylinder bore;all parts align with mounting points for direct installation without extra matched piston rings stabilize engine compression;reduce oil consumption overall power output density gaskets block oil leakage;maintain stable internal engine working environment under All components follow unified 85mm bore standards;consistent size for fit inside cylinder assembly