Last night I pulled the carb on my 2008 GS500F California Editon -_-  the carb has some strange differences from the 2004 diagram and pictures I have seen. But for reasons unknown to me I figured, "It can't be that much different, lets do it!"
Oh my god...
The PAIR and CA emission system was an absolute nightmare and although I took some pictures and I have the parts and routing diagrams, the bike now floods and dies every time the throttle is opened. I idles just fine and the choke is operating, it dies in the same manner with the petcock in the PRIME position.

-The bike sat for awhile (probably on the order of a year or two) and the fuel tank rusted badly. It was cleaned and running with an inline fuel filter when I bought it.
-Many of the hoses for the vacuum and emissions system were cracking and rotted, I wrapped the cracked bits with high temperature electrical tape and was going to make a run to a store this morning to pick up and replace those lines. As far as I can tell, the tape should keep the vacuum running strongly for a few hours at least while I grab new tubes.

Does anyone recognize these symptoms? If so maybe I routed something wrong? Are there any good instructions for removing the heinous tangle of tubes that is the PAIR and CA emissions system? How about pictures of a properly routed CA emissions bike? What are these electronics wired into my carb? Where does does the vacuum line come off of the carb?

I would really appreciate some GS wisdom on this matter.

Thanks!
spareparts

Upon observation, there seems to be a large amount of air in the (clear) fuel filter. Is this normal or would it cause fuel starvation issues?

If your carbs are flooding, I wouldn't be too worried about air in your fuel filter. I can't recall what others have done with the CA emissions tubing - but I think they left it open to the atmosphere (or maybe routed into the airbox?).

Back to the flooding carbs though: if they are flooding with the engine on, then there is a problem with your floats / float needles / float height. If they flood with the engine off, you still have a problem with the carbs, but there is also a problem with your petcock (since it shouldn't flow without engine vacuum).

Have you checked the wiki for info about hose routing and the PAIR system?

There was some debate last night about which direction the emulsion tubes right below the main jet are supposed to be inserted. Do you know if that could cause these symptoms? If I go in and switch them around and they were right the first time, I wonder what will happen? Fire extinguisher standing by, I'm going to try this.

Emulsion tube has the main jet screwed into the bottom ... and there is a pin in the body of the carb that fits into a flat spot in the emulsion tube that is keeping it from spinning -

Ergo - only 1 way it will even fit together and not need you to hammer these parts together ...

And please tell me you're not using a hammer to refit your carb ...

Cool.
Buddha.

No hammer, only my fingers!
The little emulsion tubes weren't switched, I don't even know how I could have thought they were, they definitely only fit in one way. The floats looked OK, were working before and I made no attempt to adjust them. I've checked and checked and checked the hose routing and well, it still could be f$%#ed, especially if there is a rotted vacuum hose somewhere I can't see.
As I mentioned above, I have the distinct feeling that this is vacuum related, like the needles aren't lifting because of low vacuum, from some mistake I made reassembling the PAIR system. The bike idles PERFECTLY and then the bike floods as soon as its above ~3k
Does anyone have any idea how to test this, i.e. how route the vacuum hoses to bypass the PAIR system and the CA emissions system? Or perhaps a picture of a correctly assembled and carburetor of similar year without the system.

There may be a trap (mistake) in the Clymer manual exploded diagram of the carb. Probably not your problem but we need to be aware of it.
My 1998-2002 manual page 244 shows the TOP tee and pipe labelled as Fuel inlet.
Whereas the Suzuki manual shows the fuel feed as being to the bottom tee as you would expect.
Obviously the bottom one is feeding fuel into the floatbowls so it's the feed. The top tee I presume is a vent to atmosphere.

OK, vacuum lines are good, routing is good, all tubes have been inspected and replaced if cracked. That means I broke something in the carb when I ripped it down to clean the jets.

The Problem:
The bike idles well, the choke works fine and will get it up to about 4k rpm. Any quick roll on with the throttle will stall it, regardless if the choke is engaged or not. If I roll on super slowly through the range when it would stall, it bogs down a bunch, then leaps up to about 6-7k it will not go to redline even under full open throttle. There is no gasoline in my airbox.

My Thoughts:
1)Float levels got muffed up when I unscrewed the jets and was q-tipping the rust particles out of the bowls.
2)I somehow unseated or misaligned the needles and now the bike is flooding as soon as the main jets open
3)The lifters somehow are sticking or have a partially blocked or leaking lifter vacuum line and when the mid range jet opens, the bike floods

Your Thought:
[Insert Below]

Also any relevant info or instructions hidden deeply on the internet on how to adjust the floats, needles and lifters for a newgen GS500 would also be greatly appreciated.

Get rid of the fuel filter if you haven't already, and check the float levels with a clear tube.

It failed the float check, meaning one of the float valves is stuck open, probably with a piece of junk that made it through the filter, or the float height outta whack. Thanks RossLH, I found that float check tutorial on the site.

I can't get rid of the fuel filter until I clean the tank, the inside looks like menudo, a rich red broth of rust with chunks of white tank liner tripe. I'm going to clean it today with a box of wood screws and a bottle of MEK. The maybe electrolytically with a car battery and a piece of rebar. Then I'll replace the fuel lines, clean the petcocks, rip down the carb, clean, rebuild the poor dirty thing.

I've found some good data on how to remove the PAIR system and the CA emissions system and I'll post photos of the removal and proper hose routing seeing as all the pictures are down on the old post that covers removal.

I've lamented to having my only bike out of service for the week while I clean it and get it running perfectly.  I'll ride the bus for her, she deserves it.