Just did an oil change on an X Cub with 74 hours on the tach. Looking around I noticed that the crankcase vent goes into the center of the 4 into 1 exhaust pipe like the Carbon Cubs so I looked up the tail pipe and it had about a 1/4" of opening left. I should have gotten a picture but didn't. Cleaned it out and sent them on their way. Looked on the website at publications on the X Cub but didn't see any service documents referring to this procedure but I think that it a good idea to clean it at every oil change like on the Carbon Cubs. Just a heads up so someone doesn't have an issue. Helped a guy recently that had an intermittent rough running engine and high oil usage on a Carbon Cub that had the crank case vent plugged up. After cleaning everything was good.