My wife's 2009 GS500F. I've had 2 different (questionable) mechanics tell me they rebuilt her carbs but every time I get the bike back, it runs EXACTLY as it did before.

Here's the issue... when the bike is warm it generally runs great. Good acceleration, no miss, etc. But it's a Buddha Loves You to start cold. When we first got I'd put choke on full start and the only way to get to warm was by letting it run full choke but that's like 3,000-3500 rpm. Eventually we could back choke down and idle it at 900-1100 until warm. Each new season it gets worse. Won't start with choke on or off. Have to use tiny shot of starting fluid and as soon as it starts I have to ride it around block in 1st gear keeping rpms up tp 3,000 or so, revving at stop signs, etc.

I'm looking for some GS500 expert who will either rebuild my carbs after I ship them and actually run them on a bike or guarantee the bench test so that when I bolt them on it runs like new. OR I am willing to pay for a set rebuilt, same guarantee and I give them mine like a core return.

Can anybody please help? I want the bike running great for spring. Everything else is perfect on bike.  any help greatly appreciated.

I used to do this and do a thorough job. Sadly I cant anymore - except, I can look at it and tell you what may be wrong. I would do this free, but you do pay 2 way shipping to 29063. Which means I will tell you what is wrong, not do anything about it ... so that costs you whatever shipping is X 2.

My wife would quarantine it for 3-4 days when it gets here. But I take forever doing stuff anyway cos all my tools are scattered in 1000 places and my back yard is a marsh and the tools are behind said marsh, it was pouring rain till earlier today and its dark as satan's Butthole, and cold as a freezer even in SOUTH Carolina - Yea South is in the name, but it still gets cold, who thought of that I dont know - by the time I can sneak off of work ...

OK then - reading your post - you seem to be getting the pilot jet clogged up. That retarded 17.5 or 20 VM style sitting so low in the bowl means it collects dirt and any water getting in there gets it corroded - turns blue too - Bloody hell WTH they made it out of ... no clue, and Why the F did suzuki fix what wasn't broken Again no clue. No one complained the carbs of 89-00 didnt have 3 jets. People complained it was jetted poorly to satisfy EPA and hence ran like crap.

Anyway my thought -
But it's a Buddha Loves You to start cold. When we first got I'd put choke on full start and the only way to get to warm was by letting it run full choke but that's like 3,000-3500 rpm. Eventually we could back choke down and idle it at 900-1100 until warm.

That is near normal behavior.

The problem is -
Each new season it gets worse. Won't start with choke on or off. Have to use tiny shot of starting fluid and as soon as it starts I have to ride it around block in 1st gear keeping rpms up tp 3,000 or so, revving at stop signs, etc.

That's a sign that a pilot jet is getting plugged up. Water in the fuel and jet sitting lower than the prior 40 of the 2 jet carbs etc cause the problem. Just IMHO. More like there's a big chunk of that crappy metal they made it from to screw up.

I found many many years ago a bunch of jets made from delrin. I wish they made it out of those, but they may break when you try to take em off with suzuki's wonderful quality control and how they gorilla tighten everything at the factory ...

Cool.
Buddha.

Are you sure its the carburetor? Those symptoms sound like tight valve clearances to me. How many miles on the bike and how long since you checked the valve clearances? Suzuki recommends doing it every 4,000 miles (yes, every oil change!) which is overkill but by 10,000 or 15,000 miles most GS500s will need a shim change or two to run right.

Oh yea blue - that sounds spot on.
Cool.
Buddha.

Well I know it's been more than 10K for the valves so I'll check that first. Now that I think about it that makes perfect sense since it runs great when warm and metal has expanded/contracted...

I'll keep you all informed  thanks to all!

If your carburetion is spot on but valves are just a shade too tight, the bike will start when cold perfectly on the choke, but 5 seconds in will want to die unless you keep it revved. Once it gets fully warm it will continue to run perfectly till you shut it off.
But that is only if the valves have clearance but less than the recomended.
Valves warm up faster than the head. But they expand less than the head. So a small positive clearance under the spec will turn into a negative clearance as it is warming up. But once the head warms up it expands 3X the valve and it will go back to being a small positive number.
Ofcourse if your clearance is negative to start with, forget it you need to fix that first. Of course when fully warm you may be a small postitive number but negative clearance when cold all the way through warm up = recipe to burn a valve. Negative clearance = valve is hanging open into the chamber. Valves shed heat by radiating into the head (as well as intake charge coming in) but really they need to seat on the head to keep them at the right temperature. Check em and adjust em. That little bit of "no one asked" sciencey stuff is fine to ignore.

Cool.
Buddha.