Single Piston Kit. FITS: ALL SEA-DOO 650 / 657 MOTOR 1994 AND UP. SIZE: STD. BORE / 78MM. Piston Kits Include: 1 Piston, 1 Ring Set, 1 Wrist Pin, 1pr Circlips.. Made to exact OEM specifications. **Prior to placing your order please measure your cylinders to determine the appropriate size required. Most pistons come in .25mm increments from stock or standard bore up to 1mm oversize. Refer to your shop service manual for guidance on the procedure or have the cylinders evaluated by a qualified machine shop. **.