My 99 DR350 runs great, starts great but has a noise in the motor. It happens at all rpms, it sounds like a clacking or almost like a valve tapping thats loud. I have read some things like it's normal and will run forever like this, or that it's the cam chain, or to replace the automatic adjuster with a manual one. I am confused about what it could be. I want to adjust the valves, but have seen on youtube a guy did his and the noise was the same as before as it was after. Also, if it is the cam chain adjuster and i've seen that they wear out and are famous for it, can i check it some how, and where is it? Any help or info is appreciated.