1988 2006 Yamaha YFS200 Blaster (Hi-Comp) ATV Engine Piston Ring Kit [Bore Size (mm): 66 (Stock)] Bore Size (mm): 66 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: 1988-2006 Yamaha YFS200 Blaster (Hi-Comp)