The engine has seperate bearings and seals. I used direct replacement parts. I do not know if this is a real problem or not. My other conversion engines, mostly Stihl chainsaws, do not show this trait. I guess that is why I am seeking opinions. The engine runs fine and I have put several tank fulls through it. It just rattles at idle when it is warmed up and you can move the crank up and down more when it is warm than when it is cold. If I thought a different set of bearings would cure this, I might just change them again. I guess I could just run it like this, but am a little dissapointed after replacing everything but the crank assembly.