True but only the first generation K bikes, or 'bricks' from BMW had that problem and only then because the cylinders were horizontal and pointed 'down' when the bike was on the sidestand. It was a unique situation like the lower two cylinders on an aircraft radial engine and not the norm on virtually anything else.
It is possible that the original poster really has an internal engine problem but my experience says it is nothing but condensation. Of course he could have a cracked piston, cracked rings, missing valve guides and on and on but before I would even consider anything internal, I would check to see how much internal fluid is being used. My advice would be to NOT take anything apart 'inspecting' for this problem until there was some evidence that it was oil, or anti- freeze in the exhaust vapor.
Brian
Not necessarily. Some BMWs long had a problem where if the bike was left on the sidestand for an extended period of time, oil would pool and then be sucked into the cylinder and burned on start up. I don't remember the years or models, but it was a known problem. BMW eventually fixed whatever needed fixing to prevent it. Sounds similar to this situation.