The cylinder surface looks perfect. Valves seal I checked first by leaving inverted cylinder full of fuel for a night.
None of the fuel escaped through the valves. Then I assembled the engine and keeping it upright I poured some
synthetic oil to submerse the valves. When rotating the crankshaft I looked for air bubbles escaping thorough oil. None.
After short attempts to start the engine, it did not regain compression, but I noticed black resude in crankcase.
Lower side (on one side only) of piston is rubbing against cylider and it is kind of shiny polished/grinded. Although it
shouldn't probably affect compression I suspect that new conrod is bend slightly. Otherwise what would explain piston wear
on one side?.