Sound under tank when releasing the clutch?

Occasionally when I am about mid-clutch release I hear this "electric" fluttering sound that sounds like its coming from under my tank. It reminds me of an electric current that is not completely closing and a spark is jumping between contact points. Almost like a slight buzzing/flapping noise. Anyone ever noticed this? My bike has done it for years and I'm finally determined to find out what it is. It only happens about mid clutch release and Im sure its under the tank. 2000 VFR 800 44k miles

 

I hear similar noises with my 2k as well. Mid clutch release but I would describe them more like clicking sounds on mine. I have read somewhere that off idle this could be the PAIR system. Not sure if this is true or not. I know that if I keep modulating the clutch lever in this range it will continue to make these noises.

Looking forward to see what others may have to say about this as well.

 

Sounds intriguing...

Have you got any sort of video camera/smart phone which you can use to post up a video of what is happening? As this happens whilst changing gear you may need to persuade another biker & pillion to ride alongside you so the pillion can film what is happening as you change gears.


SkiMad

 

I know that I don't hear it when changing gears. I think that the clutch motion may be so quick in this instance that the sound isn't pronounced. I only hear it when moving very slowly and modulating the clutch lever at the grab point. Road noise may also be a factor in hearing this at speed.

 

At least now I dont feel as crazy. Yes, it is under the tank, and is a fluttering/clicking noise and only happens mid clutch pull. And it will do it several times in a row but not all of the time. There has to be someone that knows what this is.... Anyone??? I hear it most when I am about to start off or at a slow roll and just barely disengage/engage the clutch.

 

We need your help first...

We don't doubt there is some weird noise under the tank of your bike, and that you sensibly want to find the cause.

But most of us are thousands of miles from Seoul so we can't hear or indeed see what you are talking about. So, please beg, borrow or steal a video camera, make a quick recording of the noise, upload it to YouTube or similar and post a link for us.

With luck someone will then be able to say what its caused by, and whether its something you need to worry about/fix.


SkiMad

 

wow mine also does this I thought at first it might be rocks kicking up then thought it was maybe a loose connection in wiring somewhere but everything works just fine. its not very audible only to the discerning ear idk if the go pro will even pick it up. maybe if mounted on the fairing idk. glad to know im not the only one.

 

YES I KNOW WHAT IS IT!!

OK I'll try to explain as simple as possible, english is not my mother tonghe, but here we go.

That noise almost makes me crazy!!, so one day I decided to investigats and demounted the tank, and opened the AIRBOX .. THE NOISE is produced by a FLAPPER VALVE, that allows more AIR INTAKE when you put FIRST GEAR and start to run, this is called PAIR FLAPPER VALVE.

As much as I know THIS IS THE ONLY MOMENT when that valve acts, when you start to take off in first gear and the clucth at middle range, only in first gear, as much as I know, doesn't actuates during other gears.





This valve is activated by a vacuum device and an electrical part commandad by THE MICROSWITCH UNDER THE CLUTCH LEVER!!

EXPLANATION:

When the microswitch is little dirty or the contacts are little carbonized, when you keep the lever in mid-range, trying to go smoothy .. THE SWITCH starts to contact-no contact-contact-no contact-contact... very fast and that produces a RATTLE NOISE UNDER THE TANK, due tha flap valve opens and close rapidily .
Something like TRRR-CLAP-TRR-RRR CLAP-CLAP.-..

IS NOT SERIOUS, just clean the clutch lever switch contyacts.

TEST.

Put your bike in center stand,
Rear tire in the air..
Remove the micro-switch from clutch lever (1 small screw)
Start the bike
press clutch, Put first gear
with the switch in the hand press and release the switch trying to pass slowly between on-off position
In some point you'll start earing the rattling noise.

Clean Contacts. That's it

THE NORMAL NOISE YOU NEED TO EAR IS: FLAP! when on.. and FLAP when off, if you have dirt contacts.. tyhe valve gets crazy open and closing TRRRRRR.

That Valve is a piece of plastic about 2x2 inches that opens-closes an extra air hole in the airbox, that's why the noise is little loud, and is operated by the VACUUM GOLD DEVICE on top oif the airbox.



Many people simply eliminates that valve, but I'm not friend of modify my Honda's "MASTERPIECE" VFR 800FI 98., for some reason must be that valve there. GOOD LUCK!

 

This makes total sense to me. I diconnected my flapper valve when I was in there doing the PAIR block off and I haven't heard the noises since. Thanks for your insight.

 

I am so glad I found this thread. I laid my 2000 VFR800 down in my driveway the other day. That happens when you're rolling the bike out of the garage, and the kickstand catches on a piece of carpet and pops up without you knowing it. ;-) Anyway, ever since this happened, I get that same vague rattling/fluttering under the tank, when modulating the clutch. I will clean the microswitch contacts when I replace the clutch lever, which was slightly bent in the lay-down.