Do you really listen to your injectors? How about your car or truck, do you open the hood and listen to them also? Yes they make a small amount of noise, THAT MEANS THEY ARE WORKING. It's not noticeable at 7800 rpm!!!!!!!!!!!!!!!!!!!
If it runs OK get on the damm thing and ride it.
P.S. I bet your butt also makes a noise when you fart!