[vincent]

Yes, take it apart.My french flathead came with only 600 hours on the counter after being completely overhauled in Clermont-Ferrant where all french flattys were repaired for the french militair. I took it apart and found the sludge traps inside the big ends half full of crap, all valves needed a bit of grinding to regain proper seats as well. Cleaned the water jackets out and made sure the internals are spotless before reassembly.The reward is now a cool running and complete oiltight engine were I know everything inside is in good order. It did cost me just a gasket set and I had to make new bungs for the crank - nothing else was needed except a bit of paint to make it look nice.