Rotary 14626 Piston Ring Compression Assembly Tool Rotary replacement part number: 14626 Replaces: Husqvarna: 502 50 70-01 Useful for assembling pistons and cylinders on chainsaws. 4 Sizes of clamps. This kit will compress piston rings ranging from 30mm to 60mm in diameter Place gasket on cylinder base, then slide the flat plate with the slot in it, from front straddling the rod. Then install your piston bearing pin and clips and rings. Select the correct red band to compress the rings leaving the top 1/8 " of the piston exposed. We suggest you lube the cylinder with a small amount of premix oil ,then slide the cylinder over the piston and install screws