Hmm... my new Enya SS30 has a suspect piston to liner fit, It doesn't hold compression very well at all, you can even turn it over with just your thumb and index finger, not by grasping the prop drive hub but the propeller nut ?
Was it like this from new? I recently bought an SS30S from Ebay that hadn't yet been broken in, had about four bench runs on it according to the previous owner. The compression is excellent.