Well, after a drawn out bunch of work and repainting the bike, I got it all back together yesterday.  I took it out for the first time today and noticed from about 4500 to a little before 6k, my tank has a really bad resonation now.  Now normally I wouldn't be concerned but it has never had it before.  I painted it the same, and put a little black strip all the way around where the old rubber on the edge of the tank used to be.  I had it off before so thats the only thing I think I changed.  Any ideas on how to get rid of that hum or whatever it is that causes the tank to rattle/vibrate/hum at those speeds???  Thanks in advance 

Are you 100% sure it is the tank?  May be something sitting against the bottom of the tank

Stupid question but are all nuts and bolts tight?

Yeah, first thing I checked.  I went through everything I took off and retorqued them.  I tried to electrical tape the control cables down to the frame and keep them down that center groove in the bottom of the tank but its still happening.  I hear it, and either pressing hard with my legs stops it, or pressing down on my tank with my left hand seems to help as well.  I'm positive its the tank.  Its like a humming sound that resonates up and down as I'm in one gear going between 4500 and 6k or so.  After that, it just goes away, and before that its not there either??

Mine does that somewhere around those RPM's.  Usually I'm just passing through though, so I guess I never really minded.  I actually sort of liked it.

Did the top rubber part that attaches to the frame fall off?   

IF all else fails try running a piece of weather stripping around the frame where the tank attaches to.

Quote from: nastynate6695 on June 06, 2008, 01:57:19 AM
Did the top rubber part that attaches to the frame fall off?   

IF all else fails try running a piece of weather stripping around the frame where the tank attaches to.

that's the first thing i thought of. mine gets all buzzy @ 4500 if the tank is almost full. usually i'll just up/down shift and it will go away.

you can put some caulk on the rubber grommets that connect the rear portion of the tank, see if that helps. haven't needed to myself just yet.

I think it's the hardness of the rubber strip.  I never had a vibe problem until I painted my tank.  I used hard plasticy / rubber door strip from the auto parts store.  Mine always vibrates at those RPM's with less than 1/3rd of a tank.

Someday I'll try a softer rubber strip, assuming I can find one.   

I'll yank off that rubber molding and see if it helps.  Also play around with rubber grommets because it never did it at all and now it flat drives me nuts.

There's another thread that may explain what you're experiencing.  My tank does this as well, and mine is missing the square cushions talked about here:  

http://gstwins.com/gsboard/index.php?topic=41939.0

EDIT:

nevermind.  just saw you posted there.

The PO of my bike droped it in his yard before I bought it.It had a nasty hum at the same rpm and got worse as the tank got lower with fuel.Come to find out my bracket at the back of the tank was slightly tweaked.Check to see if the gap around your tank is close to even and it's not rubbing the frame.Cured my problem.