Smoking Gun

[easye]

Help! I bought a used (2001) 400EX that is burning lots of oil. I just changed the rings and the problem has gotten a little better but comes back during acceleration. Any suggestions where to go next?

[UglyMotha™]

did you make sure that your cylinder was not outta round when you did the rings also did you hone the cylinder

[sickmojave]

what kind of shape are the valve guides and seals? :confused:

[skemp]

Get the cylinder bore checked for roundness and tolerances, check the valve guides and seals (I suspect this), and get the valves reseated. You should find your problem somewhere in this process.