Poping the head off...

[SoFlo]

If I were to pop the head off of my RM250, I could just put it back on without any new gaskets? Does it have an o-ring or a gasket? How about draining the coolant and everything? I need to take it off to inspect the topend, I'm trying to get the bike running a little better.

 

[motometal]

You must drain the coolant, at least most of it. The "textbook" correct method would dictate replacing the o rings, but unless they are damaged you could probably get away with not replacing them.

that reminds me: I turned my '96 RM250 into a 300, it ran great but did have a few issues because the material between the inner oring and the inner cylinder wall was now very thin. I ended up using a viton oring and some silicone, and my problems went away.