Good evening, dear congregation, I turn to you in the hope of finding advice and solutions. I had a used Kawasaki ER6n, ABS, reduced to 34hp about 5 weeks ago. Kilomterstand: ~26500 km For a while everything ran round, but then the following symptoms occurred (chronological): The main problem is here (5). I have listed the other points only to facilitate possible conclusions. You never know about (5): Before driving (cold engine) is t the cooling liquid just below , after the ride, when the “bubbling”, the liquid stands scarcely . Furthermore, this morning (short drive in the morning , no bubbling ) I found that a thin bubble layer had formed on the oil (no discoloration ) and the oil level glass was fogged from the inside . First diagnosis would certainly be cylinder head seal , but I would love to discard the thought . There is also no white smoke from the exhaust . Leichsbehälter are not to be seen either. Since I am a bloody beginner, I would be grateful for any diagnostic advice. If possible, describe this gladly a bit more in detail, so I can learn something directly I am grateful for any help ! PS.: Who can come up with solutions for (2), can also share them –> unfortunately is not fixed yet and the Mechs could not fix anything either.