I just finished cleaning, syncing (eyeball, but I'm pretty sure both butterfly valves are dead even) and jetting the carbs on a '04 GS.  From completely stock and running, I went to a lunchbox filter and 20/62.5/140 jets.  I know that a lunchbox and stock exhaust is sketchy, but the bolts inside the stock airbox broke when I took it off.

Here is my problem:
Bike has difficulty starting w/o full choke and a little bit of throttle finesse to get it > 500rpm.  Idle with choke is shaky at ~1300rpm and if I give it some more throttle it will hover at about 3500rpm until I let the choke off.  Once I do that, the bike will stall or idle roughly at 1100rpm before stalling.  Turning up the choke again at that point does nothing - the engine will still stay at 1100rpm and eventually die.  If I give it a good amount of throttle, it will go up to ~7000rpm and then stall completely.  All over the band, there are varying amounts of vibration.  Also I get the occaisional misfire that causes RPM to droop briefly.

-I checked the petcock/fuelhoses/bowls, etc.  Nothing is pinched or on the wrong setting.
-I tried spraying some carb cleaner around the filter>carb and carb>engine boots, and nothing happened.  I did accidentally spray a bit on the filter and the engine died.
-Checked the plugs, they are black, but not terribly fouled.  They were like this BEFORE I took the bike apart.  I'm probably going to pick up some new ones if nothing else occurs to me.
-the idle air screws are tightened on each bowl.  Any less than tightened and they will quickly vibrate open, spilling gas.

Any suggestions?   

Quote-the idle air screws are tightened on each bowl.  Any less than tightened and they will quickly vibrate open, spilling gas.

That doesn't sound right.  Is there a spring and o-ring in there?

There isnt :/

Looking at the carb diagram on bikebandit, there doesn't appear to be any o-ring/washer.

We are talking No20 here not No31 right??? 

http://www.bikebandit.com/showschematic/m9752sch510170

31 is what I'm talking about.

31 should be tightened. This is to empty the bowl.

No21 is the mixture screw and as a starting point it should be set at about 3 turns out, from lightly seated.
No 40A is a plug that covers the screw and should be drilled if it's still on the carbs.

Also check the fuel level in the carbs. So the gurus  have the full picture, as it will be easier to help you.
http://www.gstwin.com/float_height_check.htm

^Ah yes, I did check the float height and it's fine.  Sorry, forgot to mention that.

PS: the mixture screw is set at 3 turns.

Wow, you guys are not going to believe how retarded I am.  I was putting my tools away when I noticed a pair of springs in the tool tray...

Thats right - I FORGOT TO PUT THE NEEDLE SPRINGS IN!

Well lo' and behold: the powerband is fixed.  Revs all the way up without issue (I'll need to see how it does on the road).  The idle is still a little rough below 1500 and rpms don't drop as fas as I would like when I let go of the throttle, so it seems to be running a bit lean.

Quote from: jvitzu on September 07, 2009, 03:01:43 PM
Wow, you guys are not going to believe how retarded I am.  I was putting my tools away when I noticed a pair of springs in the tool tray...

Thats right - I FORGOT TO PUT THE NEEDLE SPRINGS IN!

Well lo' and behold: the powerband is fixed.  Revs all the way up without issue (until I take it out).  The idle is still a little rough below 1500 and rpms don't drop as fas as I would like when I let go of the throttle, so it seems to be running a bit lean.

LOL

I have done it too! LOL..

It was the needles fault I tell you, it did it on purpose!!!