Is it possible to remove the number one piston without pulling the engine? This is a USA model if it makes any difference. I had blue smoke filling the engine compartment, rough idle and lowpower. The back 3 cylinders were all 155lbs but the front one was 90. It came up 5 lbs with a spoon of oil added. Re-torquing the head didn't change anything. Head removal didn't show any problems with the gasket. The cylinder isn't scored. Inspecting the valves faces while still installed in the head show they aren't carboned or dirty or distorted or worn looking. Any ideas? Thank you for your time.