Hello all, I am new to the group and had a question maybe someone can help me out. Recently picked up a 1987 250ES that’s in pretty good shape and runs good but SMOKES like real bad. Previous owner did a top end rebuild and posted a video of it so I have proof he’s not lying. Anyways he had the cylinder machined, replaced rings, replaced valve seals and lapped valves, cleaned the head up real nice and no change. Still smokes like a chimney, I’m kinda at a loss previous owner was saying the crank oil seals needed to be replaced but I’m not sure. He ran it for awhile after rebuild to make sure it wasn’t just in the pipes and I have not done a compression test yet. Any help would be appreciated!