my gsr made a similar noise when I was running 5-30 in my car. I had my valves adjusted, got some injector cleaner, and changed my oil to 10-30 and the noise almost totally went away. When the honda engines get a little older with more miles, it's a good idea to change to 10-30 b/c 5-30 just doesn't give you enough protection. It also depends on your location. Different altitudes and outside temperature ranges during the day make a big difference too. You are running n/a right?