1999-2006 Honda TRX 350 Rancher ATV Engine Piston Ring Kit [Bore Size (mm): 78.46 (Stock)] Bore Size (mm): 78.46 Ring Kits Include Piston Rings Only - Piston Not Included Namura Piston Rings Fit Both Namura and OEM Pistons of the Same Bore Size Unless Otherwise Specified Compatibility: 1999-2006 Honda TRX 350 Rancher