I messed up, and did not properly lock down the locking nut on a tappet doing a quick valve adjust. In the next ride, top end was not as it usually was, so I pulled off the valve cover, and found my problem. Tappet is toast, so I will be getting a new one, but I wondered about damage that I may have caused? Also, I noticed on the cam followers that there are a couple of dished out areas where it comes in contact with the cam. (This bike is a 1991 XR600R, but new to me in the last couple of weeks.) I was told that somebody was not dilligent with the oil changes, and the hardening flaked off the original cam, and a new cam (along with new valves) was installed in mid '06. (I do have the receipt showing parts ordered, all of it seems like a tight story) As I was looking at the valve cover, and all of the cam followers (and lifters?), I noticed that the surface that mates up with the cam is dished out a bit. Should those things be smooth and polished? Mine looks nice and shiny, but these "waves" along the cam followers has me curious. Thoughts? Thanks.