kdx 200 trouble

Could it be that the impeller shaft is grooved? The bike is getting older and things like that could wear out, especially if it was ridden with a bad seal for some time. Also, check to make sure the window isn't just filled with the "milk" by draining the oil and removing the cover (should be able to reuse gasket if you're careful) and cleaning the inside of the window with parts cleaner. I had this problem, the foam was just staying in the window area making the oil look milky. If thats not it flush the cases out really good with some cheap oil. Good luck! ;)