I have 3 of them. One of them in my Ultimate inhaled a small washer or something metal and scored the cylinder and piston. I ordered a DLe55 ccylinder and piston and ring from tower. All I had to do was drill out the cylinder mounting holes one drill size larger to mount the cylinder. There was a slight difference in bolt spacing. Less than a mil from front to back. It runs great and runs smoother at idle than the stock RCG. The porting on the dle55 is much nicer than the rcg50 cylinder. Nice crosshatch and the ports are more open than the rcg. I have about 8 flights on it with Penzoil 32 to 1 to seat the new ring.