can't anybody even come with an educated guess? diesel.

yes and yes,darn good questions, though.'cause only audible when throttle is completly closed. bought '03 used, mixture screw out 2 1/4 turns. never had slide out yet to check white spacer or bowl off to check jetting. exhaust stock, but header pipe is a VERY light gold after 3300mi. no blue no place.runs real good to 80 mph with throttle left for more, that suites me all to he!!, back fires are very few and far between and when it does backfire,it's very light, more like a futt than a bang and only from closed throttle from high rpm. i'm from the old school, if it ain't broke, don't fix it. all this and averages 55 to 60 mpg pushing a plexistar 2 shield. all this kinda indicates fuel raito through the rpm range is pertty darn close. if and when it starts to act up or milage drops off, i'll break 'er open and have a peek. till then, i just gonna ride 'er, let 'er chirp and be da$$ed.Bill aka diesel.

follows engine rpm, decelerating,pull clutch, chirp gone, reengage clutch,bike still pushing engine, chirp,chirp comes up with rpm. crack throttle, gone. now it ain't real loud, actually, kinda faint, but iffen you listen, you can hear it, don't think it too serious. some day when poor running indicates, i'll pull carb,in that area somewhere. mabye i just otta wear a full face helmet, i know i would never hear it then.  diesel.

Greg: thats just it, diesel tech NEVER has to tinker with no stinking carburetors. it's a learn as you go process for him. high pressure fuel injrction and no throttle of air, a whole different set of rules for running an engine. fuel/air ratios will run 500 to 1 or more at idle to 30 or 40 to 1 at maximum engine load. only control amount of fuel engine receives, no control of air it receives, turbochargers just blow in more air so more fuel can be injected= more torque from same displacement engine. so as long as my little beast runs as good as it does, my learning curve on thoes stinking carburetors will just have to wait a little while longer. diesel

how right you are, maybe not carb, maybe something else. iffen it gets worse, I'll find it.

Diesel, I'm not a technician, but my other bike is a...
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1980 MGB english car, right hand drive and all that, and it chirps, rattles, sighs, moans and more! all the way from startup to shutdown.

Check and see if all the engine-frame bolts are nice and tight, it could be something is jiving because it's just a leeetle loose.
Or, see the clutch bearings, or the final drive front sprocket. You say it only happens when at high revs and closed throttle. Well, to me this spells high revs, torque applied from road to engine and not as it should be, so with force being applied the other way 'round, I wouldn't be surprised.

Let us know, it could be important

Maurizio

Diesel,
No adjustment cured it, only removal. Kinda blew my mind, but like I said, it cured it!
I listen to my baby when she talks!!

Good Luck

Jim