I bought a fairly used 05' yz450f this spring. It had a small oil leak on the countershaft. replaced the seal now it's fine. But now the shifter seal is leaking along with something else right in that same area. I was just going to continue replacing seals but my dad suggested that I might be getting pressure past the rings pushing the oil out. I checked the breather tube and it is clear. Are these bikes known to have little respect for there fluids? Any suggestions would be a great help. Thanks in advance.