I have had this chronic problem lately with both my YS160/170DZ. Even after both enginese were checked out at YS Repair d to my leakage issue there is still a huge amount of burned black oil all over the inside of the nose cowling.
I had noticed that the header would slide fairly easy over the O-ring of the Hatori muffler. So I even bought a new set of both Hatori header and Hatori muffler and new O rings and the problem is still the same! I still noticed that the seal does not appear to be tight with the new parts.
I still think that it must be leaking at this interface so my next try is to add a narrow strip of aluminum tape to the inside of the muffler groove to see if I can get a tighter seal around the O ring by pushing it inward due to shrinking the groove inside diameter.
Any inputs?
Has anyone experienced this problem?
Thanks.