Misfire solved

Hi , 2005 Mini Cooper convertible with a misfire , I bought as a non runner with broken chain , fitted new chain and sprockets, guides . Started with a misfire did full service inc leads and coil pack , fuel pump , filter , regulator stil PO301 , compression tester was 210 2-3-4 and only 150 on 1 , decided take head off gasket seems ok as do valves , filled combustion chamber with petrol and straight out of exhaust valve on cylinder 1 , new valve fitted with gasket etc all good now