Hi all. Just put a 540 kit on my exc and had a valve job done. When i was picking my head up from my mechanic he was saying something about a nut on the crank that can sometimes back off and cause some bottom end "rattle". Now maybe that just got me a little paranoid, or maybe its because i haven't heard the bike run in like 8 months but i seem to notice a little noise that doesn't completely go away when you pull the clutch in. Now is this very common? Or something ti be concerned with, or am i thinking too far into it? He said you can somewhat check to see if that nut is loose by looking in the oil filter housing(s). Can anyone confirm this? Or had a similar issue? Thanks in advance.