Hi I've been looking around this forum for a while now, and I decided to write my first post. On my Crf 450 I've just replaced the countershaft and 3 and 4 gear on it, due to a broken circlip that managed to get in between sprocket and shaft. :-( While reassemblying the engine, I started to wonder how the oil "travels around the engine". I can see that the oil pump is taking oil from "crank compartment" through a one way valve, then through the oil filter and at last spraying it pack under the piston. Am I right or wrong? There is a valve just beneath the oil filter chamber, can you test it just by trying to blow through it? In addition to this I see no connection between the tranny compartment and crankcase compartment. How are the oil in tranny then cleaned or isnt it cleaned at all?