i got rid of my r1 to get a quieter sounding bike but the 05 rr i got has some decent tapping around 4-6k rpms, i thought it was the cam tensioner so i took it out and it holds pressure just fine. im replacing it anyway but i dont think thats the noise. its loudest near the injectors but id be suprised if injectors were tapping that loudly , the valves were checked and within spec at 20k miles. its at 25k now. rides great just a bit noisy at higher rpm, the warmer the bike gets i hear it louder. heres a vid of the tap.