For quite awhile now I've noticed a sound from the engine as soon as the throtle is opened. It sounds like tapping on a hollow can... sometimes 2-3 little pops just off idle. I hear this with my ear plugs in and need to try it with out to see how loud it reallly is. It doesn't seem to be there while the engine is not up to operating temp. Pulling away from a stop is when it's noticable. Anyone else notice this sound? Should I be concerned? Thanks guys.
If the noise is from under the tank it will be the flapper valve. I have copied this from a UK VFR site and take no credit for it: On the airbox there's a variable intake system, this includes a vacuum operated, electronically controlled flapper valve that opens and closes at various times. In normal operation it should operate and open at about 5000 - 6000 rpm, but there are many times it'll operate outside this region - for example it's open when the bike is in neutral, but closes when taking the drive up in first gear, it's that function that allows you to confirm it is the flapper valve making the noise
same thing here I seem to have exact same problem. If I turn the throttle just a little bit and hold it while in neutral I hear a very light flap.. flap.. My bike is still under warranty, can this be fixed or not?
