"Chirping" from the exhaust

[Sheep]

Hello!
I'm usually in the manufacturing and quality forums but I've run across a personal problem I cannot seem to find the answer to, so I thought I'd run by the motorcyle engineering folks and see what I can obtain.
I have a 2001 Yammie 1100 V-Star classic (Cali model with the AIS). I've diconnected the AIS some time back to rectify the back-firing issue and all was fine - UNTIL I put the "straight-thru" baffles in my Hard Krome pipes. NOW I hear a "chirping" from the exhaust and it's driving me crazy, trying to figure out what it is. I got this bike with 8,000 on the odo and the guy I got it from told me he had the carbs re-jetted when he put the pipes on, so I haven't worried about the mixture being too lean until now. CAN an incorrect mixture (too lean) cause this? Any help would be GREATLY appreciated! I've heard stories about V-Stars chiping due to the AIS but since I haven't noticed it until now, I' am bit concerned. Thanks all!
Sheep

 

[Pressed]

It might seem weird but metal on metal contact with vibration can sound like chirping. Is it rpm or speed related? One logic to possibly apply is "it's the last thing that was changed". Good luck.

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[Sheep]

Thanks, Pressed!
I don't KNOW for certain yet; it seems that I hear it more under throttle but that all I can pin down so far. Yes, that IS the logic I am attempting to apply, that is why I asked if anyone knew if it could be a mixture related phenomenon, since I just changed the baffles to a more free flow type. That is ALL that has changed in recent weeks or months, really. Thanks again, however,....it COULD be, possibly, based in the fit of the baffles themselves from what you suggest - I did notice that these new ones don't fit as snugly into the reduced diameter pipe "neck". (?)

 

[Pressed]

If you take the baffle apart and see some rubbing or such and can't see a fix, try to determine if you can apply a layer-ribbon-wad-etc of steel wool to see if that makes a difference. They pack baffles with steel wool but this might only be a step to a solution. Without seeing the parts I can't tell if this is a permanent solution.

I have never heard or experienced chirping from the mixture. I have experienced a cracking sound (engine hesitates-misfires) as a result of the jetting being incorrect, maybe that is what you are having?

The way I know to check my mixture is to make the color of residue at the pipe and plugs look milk chocolate to chocolate brown. If it is really white or really carbon black, the mix might need adjusting.


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[Sheep]

Thanks again!
I was a little concerned about the baffles leaning it out too much and that was why I was wondering about it. I did check the plugs today and they are nice and brown, so now I know that the last owner MUST have rejetted it - between the Hypercharger (which I forgot to mention but it's been on since I bought the bike 20,000 ago.) and the Hardkromes, it would be running VERY lean with the stock jetting. I knew I had an exhaust leak on the front cylinder and I fixed that today....it DID seem to help the chirping! I only rode 30 miles or so, so I can't say it's "gone" but I didn't hear it HARDLY at all today.
I will most likely try what you describe, in some fashion at least, with the baffles fit issue. Now HERE is what really brought all this to mind in the first place; WHY did the old VW's always have that CHIRP to exhaust note? I always assumed it some sort of inherent valve noise. (?)
Anyway, thank you again. I can't EXPLAIN why the leak would cause the chirp but, as I say, it did seem to help it!
Sheep

 

[Pressed]

I once took the headers off my 900F and started it for a few seconds and it sounded a little like to a VW. The air sound from the valves was dominant, siphon noises kinda.

The comparison to the sound with headers on, well, there was no comparison. As different as can be imagined. The exhaust system plays a major factor in the sound of an engine.

VWs sound different for numerous reasons: crankshaft TDC positions being 180 degrees apart, the firing order (fire, fire, wait, wait), and the short/small exhaust system. Of course I am no VW expert, someone might come along and give a better description here.

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[sreid]

The chirp in VW exhausts is usually from combustion gasses passing through burnt exhaust valves.

 

[Sheep]

Thank you both for the info! Sorry I haven't gotten back sooner but I've been away for the week. That "burnt exhaust valves" is exactly what I DIDN'T want to hear though. Hopefully, it is not that!