[Zachattack1500]

I have a 2005 crf250r put new valves,piston, cam chain, and still makes this noise.

[crfsonly]

It's very difficult to diagnose an engine noise from a youtube video. However, most engine noise like this typically comes from the valve train. Common sources if this is the case are the decomp mechanism and the cam chain tensioner. I recommend removing the decomp and applying a very thin layer of a very thin assembly lube or if you don't have this use some oil liberally on all running surfaces. Make sure the decomp and the spring are installed correctly. One common mistake is over wrap the spring. Also inspect the cam chain tensioner for wear, proper function and correct installation.