Weird Engine Noise I Can't Identify, Input Needed

Hey guys. Haven't been around that much lately as I have been swamped but I wanted to pick your brains about the recent issue I have been having with my 6th gen.

Like any issue, it's a little tough to describe over the internet but here goes.

At speeds above more or less 50km/h (lets say 35mph and up), when I let go of the gas I hear a sort of clanking noise coming from the front of the bike, most probably inside the engine, and it lasts no more than 5 seconds, then it goes away. It almost sounds like when you forget some change in the dryer. Now, it does not happen when I am giving it gas or at lower speeds. I also cannot replicate the noise standing still and giving it gas. No noticeable difference when the ambient air is warmer or colder or when the bike is cold or hot. The noise is loudest when I give it WOT then let go. Apart from the noise, the bike has been handling itself exactly like it was before. No recent mods, the latest were to remove the snorkel and block off the pair valves but that was 3 months and 3000km ago.

Any ideas? Any help would be greatly appreciated.

Thanks in advance!!

Not sure if it's the same noise but I looked at a 2004 VFR a little while ago that had a strange rattle type noise coming from the front of the engine. The owner said it was a noisy cam chain tensioner. Was very noticeable when started from cold and it went away as it warmed up. Not sure if this is the same kind of sound but maybe check out the following thread.

http://www.vfrdiscus...hain tensioner

Thanks Zoomzoom. I had looked into that issue a while back as my cam chains do make some noise but the consensus seemed to be that they either make noise or not (new or used) and it didn't really make any difference so I learned to live with that slight rattle. This noise is different though and does not evolve in any way when the bike warms up.

Unless someone confirms this new noise could be some sort of evolution of the cam chain noise, I do not think that is what it is. But I don't know, that's why I am asking :goofy:

Thanks though!!

Maybe you're only thinking it's coming from the front and it's really being funneled by the fairing up that way?

How's the chain look? Maybe when you really get on it and then let off you're getting some serious chain slap, which will dissipate after a couple seconds?

Just a thought.

Next time you let off the gas, also hit the brakes and see if that exacerbates the noise. Maybe front wheel bearings, although that seems very far fetched.

Interesting. I had indeed thought of the noise rebounding off other things and had considered the chain being the culprit as well. I cleaned and greased it today before going for a ride and it did not do any noticeable difference so I kind of put it aside.

After numerous bikes and 10+ years of riding this is oddly enough the first bike with a chain I have kept for a while so I am certainly no chain expert. It looks ok to me but does seem to have some tight spots (ie it goes up and down when I spin the rear wheel by hand).

I will try the above suggestion to see what it does. I will also try to reproduce the noise on the center stand. I had tried reving it on neutral but had not put it in gear.

Thanks!

CCT rattle tends to happen when cold at idle or shortly after, and many times dissipates once warm(the most common), but can also rattle on decel at times and the bike has been running for hours. CCT noise can also rattle at idle, whether cold or hot. So there's no fixed guaranteed path with cct noise. But cct noise is a rattle or clack clack like a duck.

For you to only have decel cct rattle from high rpm and none of the other types would be strange.

update:

I tried braking after letting off the gas and it did not seem to affect the noise in any way

I also took a few pics and shot a few videos of the chain while I revved the engine. Although I was unable to reproduce the noise (being on the center stand I of course had to pull in the clutch quickly after letting off the gas) there was noise coming from the chain and that chain does look really iffy now that I see it in action.

https://www.youtube....h?v=u3Omw0uf7MQ

with revs

https://www.youtube....h?v=jsICO2w2d8Y

with more revs

https://www.youtube....h?v=PYrcihL7QCI

and a few pics the chain (it has been a little rusty since forever). I've had it for 3 summers now and about 20000miles:

[image: IMG_20140929_165634_857_zps5535d571.jpg]

[image: IMG_20140929_165647_417_zps9234626d.jpg]

thoughts?

Thanks!!

It's hard to tell from the angle of the pictures, but it does seem to be hanging a bit low.  How much slack is there?  If it's more than a couple of cm it's probably slapping.  Add a couple of kinks in the chain and there you have it.

Rusty when you got it and 3 years 20000 miles, time to replace that.

. It looks ok to me but does seem to have some tight spots (ie it goes up and down when I spin the rear wheel by hand).

No es bueno. Lube good and eliminate tight spots now, and replace later.

Or just replace now. Sprockets too.