[Makedon]

My GZ 250 didn’t want to start. I rebuild the carb , change the oil, new spark plug. I check the compression with my tumb ( finger) and it gave pressure on the spark plug hole. I ended baying a engine compression gage/ tester , and check the compression. It was showing 70psi. Very low compression. I opened the valves and did valve adjustment( they had zero clearance), I followed the service manual instructions, went ahead check the compression, and again it shows 70psi. And now I’m stuck. Is there anything else that I should do or check, or Should I start thinking about replacing the head gasket, or maybe even worse the piston ring. The bike is 2009 with 7700 miles on it.
Thanks for all ideas and suggestions.