Funny little sound when throttle is opened

I have the same problem, is the sound on your bike. See my video

 

Yep, that's the same sound.

 

Did you find out what it was ??? The try to unplugg the hose intop of airfilter, but the sound was Still there

 

The sound is still there and I give up trying to find out what it is. It doesn't effect the Bikes performance and hasn't gotten any worse.

 

ok, but very annoyin... I will write if I find out

 

Mine does that too. Hs for years and tens of thousands of miles. I think it may just be the flapper on the air intake opening and closing but not 100% on that.

 

The flapper is vacuum activated, but the vacuum is turned on/off by an electrical solenoid. I suspect it is the solenoid that you are hearing, certainly on my 5G in gear with the clutch in at lights I occasionally hear the solenoid activating if the clutch switch is a little dirty. To test if it is the solenoid, you could unplug the clutch switch (don't worry, it won't make the bike explode, you just won't be able to activate the starter when in gear) and see if the noise stops.

 

I have replaced this switch and the sound is still there....So then it means that it's not a solenoid i will think. Was at the mc workshop and replace this one today, but thanks for the tip