I recently had a shop install a manual APE CCT on my 04 CBR600RR. Not sure if they did it correctly? But underload the bike makes a buzzing/vibration resonance throughout the RPM band that I didn't really notice before. I know what the " tick" sounds like when its too loose like BB's rattling. I readjusted everything myself and made sure its not too tight/loose. Only thing I can think of is maybe something is loose? I checked my fairings, bolts, etc. Worse case perhaps a timing guide was damaged somehow?

Timing seems ok. I haven't take it apart to verify, but it idles and rev's fine. I called APE they weren't of any real help.

 

Most likely it's still a little lose. Although I don't think this is a problem -too tight is problem- if it annoys you then try 1/4-1/2 turn more and see if the buzz is gone.
Getting the sweet spot on an aftermarket CCT is a PITA...needs many iterations