Sounds like you're replumbing fixed the problems. My best guess is that you had a pinhole leak in one of your lines, probably inside the fuel tank. That would explain why the engine would lean out and starve when you shook the plane around (flexing the klunk line introducing air. It would also explain why the plane would be fine on the ground but die in the air. Vibration and motion of the plane throwing the klunk around, introducing air, leaning out the engine in flight, subsequent heating up of the cylinder, and loss of compression. If the engine is running now, keep flying and have fun.

As for the leak around the front bearing, its supposed to leak. During the stroke there will be a short period of time when there is sufficient pressure in the crank case to force oil and fuel out through the front bearing. This is essential to lubricate the front bearing. The seal on the bearing is to keep dirt out, not fuel in. That seal could be a little looser than normal, but still be within tolerance, and that will cause more fuel to come through.

If the fuel and residue on the inside of the cowl are black, its another sign of the engine being too lean. Hopefully fixing the tank will reduce this. The oil on the side of the plane should be clear, or slightly colored at the worst. Black inside the cowl could also be a sign of vibration induced metal wear. Check your exhaust bolts to ensure they're tight. Also make sure head bolts are tight.

Brad

Brad