Hello, My name is Tomas and I live in Czech Republic in Central Europe. And of course sorry for my bad English. I am contacting all of you for advice when I am finding a solution for my specific problem. I believe that there are skilled mechanics among you with many years of experience can help. I recently bought an Indian Four motorcycle from 1932. The bike is after a complete renovation, including the engine. And just when the engine was running in, a fault appeared that I can't handle. The third cylinder burns the mixture imperfectly, it works at about 30%, the spark plug is after disassembly wet and unburned. The other cylinders work without problems. I was able to rule out a fault on ignition, including another cables and spark plugs (I use NGK AB-6). This indicates me a problem in the mechanical part. The compression on all cylinders is about 4.6 atm (67.601 PSI). Valve clearances are: intake valve=0.15 mm (0.59 in), exhaust valve=0.25 mm (0.98 in). The engine willingly starts and responds quickly to the accelerating of throttle. That the cylinder does not work properly, despite the spark plug spark gives, I detected using a thermal camera (see attached, heat difference between 3rd (70.73°C=159.31 F) and 4th cylinder (127.15°C=260.87 F) . I want to ask you for advice if someone would give me the answer where to look for a problem solving. I've heard that third cylinders have always had a problem, but I can't believe it's been over 1 hour engine run-in. Thank You for all your advices and responses.