Hey guys! I'm a newbie on this forum, so first of all I'd like to say that I find ThumperTalk very helpful and well organized. All the members, but especially the moderators and old veterans, deserve a "thank you"! I have a '04 CRF 250R. After I had the valves adjusted by a mechanic, I noticed there is some oil leaking from between the cylinder head cover and the head. At first I thought that the gasket had been installed wrong or it was cracked, so I took it back. I was then told that the oil is not leaking between the cylinder head cover and the head but it is rather coming thru the breather tube at the top of the cylinder head cover: because the valves had been adjusted, there is now more compression in the cylinder and some gases are escaping between the cylinder wall and the piston rings and this added pressure pushes out the oil...Well, it all sounds good, but wouldn't the oil leak thru the crankcase breather tube? I mean, the gases escape below the piston, into the crankcase, right?! How would there be added pressure above the head itself ?! Or is it that the breather tube from the cylinder head cover is actually venting the crankcase? Any help is apprecited! Thank you very much!