We are repairing a head (broken timing belt) that was totally trashed. Most of the carbon deposits were on the top of the cylinder heads with the peri-valve area of the combustion chamber relatively clean in comparison. Since the current head was ruined we removed the head from the original factory Honda engine that we still had ( the current is a replacement engine) and noted that the carbon deposits were almost exclusively in the valve port area with the cylinder top of the piston relatively clean. That seems strange to me! Is there an explanation for that phenomenon or why the difference it is after all the same engine.. Anyone have any insight into what I am describing? wolf