Top end wisssssh wisssssh noise on a 96 B6.

[Oldschooler]

I have a 96 B6 and though it's running great it seems to be making a wisssh wisssh noise on top when it rev it. Not a vacumm wissh noise, more machanical. It also seems to be minor when cold but louder when hot.
I was thinking it might be the timing chain but every sound clip I've heard of the tensioner not working seems to be more of a random click clack noise at idle. Almost like the chain is skimming along the inside of the engine somewhere. Mine is quiet at idle. I just adjusted the valves and took a look around while in there and everything looked ok.

Any ideas, or anyone know what this is?

[ricklee4570]

I have a friend who has a B-6 that does the same thing, a wisshing sound on the throttle, not so much at coast conditions. I noticed it when he let me ride it. He has 42,000 miles on his and he says it has been doing this since he got it at 32,000. So I guess it must not be too serious!  If yours is the same as his anyway!

[pmackie]

Is it rpm sensitive? Do you hear it only under certain load/throttle/rpm conditions?

Try to determine when you hear it the most and repost.

[Oldschooler]

Well at idle you can hardly hear it at all. Rev it up and it gets louder. Once it gets to about 3500rpm it doesn't get any louder just faster. It is proportional to rpm.

[Nitro]

Leaky airbox or carb boot?

[Bob Holland]

Broke compression ring, leaking valve. Do a compression test.
If the bike is running good and making the noise, then it is probably not a ring.

[pmackie]

I'd take another hard look at the whole intake system.

Check all vacuum hoses, look for cracks in the intake boots, look at the carb to airbox boots, check the top of the carbs, etc.

Maybe get another mechanically inclined biker friend to listen as well.