Hi everyone! I'm fairly new the motorcycle world but heard this was a great place to talk with fellow GS500F riders. So far I've been able to do most of the work successfully by myself (tire change, chain, sprockets, handlebars..) but when I headed for the carburetor I seem to have messed up. Looking for advice before I see a mechanic.

Two weekends ago I was riding (on a really hot day) and the engine kept shutting off. Sometimes it was when I tried to switch gears (up) and sometimes for what seemed like no reason. Wasn't sure if it was a gas issue so I let it sit on reserve in shade before filling it up with premium. Got it home with no issues. A few fellow riders suggested it might be a clogged carburetor (bike is only at about 3k miles) so I took it out, cleaned it, replaced the needles, and put it all back according to how I took it out (wires and all).

Now it won't start/idle. There is also a clicking noise that sounds like it's coming from the back of the bike when I'm holding down the starter. My next thought is that I either seriously messed up somewhere (and don't know where) -or- it's the battery.

I'm itching to ride again and still do the work myself if possible. Does anyone have suggestions on what to check for and/or look at? any comments? concerns? recommendations? Photos and step-by-step instructions really help me if you have them.

welcome Brooklyn
Let's break this down to two separate problems.
1) "Won't start/idle".  The more specific you can be about this, the better. Is the key on? Run switch on?  Side stand up or down?  In gear or neutral?   Is the starter running?  Is the engine catching/coughing/back firing?  Anything like that.  Without knowing anything else, I'd suggest going back over everything you touched taking care to see if there are any missing electrical connections or frayed wires.  Pay special attention to the battery terminals, grounds and side stand and clutch switches.
2) Engine shutting off.  We'll get to this once its running again.  Not much to go on but I'd guess it's the side stand switch so fixing problem #1 may be all you need.   

Let us know how it goes.

1) "Won't start/idle".  The more specific you can be about this, the better. Is the key on? Run switch on?  Side stand up or down?  In gear or neutral?   Is the starter running?  Is the engine catching/coughing/back firing?  Anything like that.  Without knowing anything else, I'd suggest going back over everything you touched taking care to see if there are any missing electrical connections or frayed wires.  Pay special attention to the battery terminals, grounds and side stand and clutch switches.
Key on; run switch on; side stand down and in neutral (how I usually start it with no issue)
starter running? excuse my lack of knowledge but I'm not quite sure what you mean here. If you mean does the starter button (on the handle bars) work.. no amount of pressing/holding works. It makes the starter noise but the engine isn't catching (no coughing or back firing). That's also when I hear the clicking. Happy to give it another once over to see if I missed any connections (last I checked everything was plugged in where it needed to be).

2) Engine shutting off.  We'll get to this once its running again.  Not much to go on but I'd guess it's the side stand switch so fixing problem #1 may be all you need.   
Definitely need to solve issue 1 first lol the side stand wasn't down when the engine was shutting off. I think I was riding on a highway in 4th or 5th gear around 50 to 60 mph.

The clicking sound is a symptom of a flat battery. It's the solenoid dropping in and out. You need to charge it before anything else

As for the non running issue it could be any one of a number of things. Checking for a good spark and that fuel is reaching the carbs by cracking the drain screws are the first steps but if it was ok before you worked on it I suggest you revisit what you did.

You just need to retrace your steps. Something you did with the carbs off is causing the current behavior.

Is it getting fuel? Is there fuel in the float bowls? You can check that easily by opening the float bowl taps and verify some fuel drips. A thing I do all the time is put the bike all the way back together only to find I forgot to open the tank petcock.

You tried it on PRI? Maybe you flooded it.

And of course there's a dozen things you might have screwed up putting the carbs together. You said you took the carbs off, "replaced the needles", and "cleaned" them. How exactly did you do this? What "needles" did you replace?

It's fairly common to damage the diaphragms by spraying carb cleaner into the carb with the diaphragms in place. That probably wouldn't prevent the bike from starting, but it might prevent it from running well once it did start. It's also pretty common to leave out an o-ring here and there when putting carbs back together. And it's surprisingly easy if you remove the main needle to assemble it all wrong and wind up with the needle stuck so the slide stays wide open. That would definitely prevent the bike from starting.

Other things, are you sure the fuel lines are hooked up right? Did you happen to disconnect any wiring while taking it apart? etc.

"It makes the starter noise but the engine isn't catching."

Do you mean the engine is turning over but not firing up or there is nothing, just clicking?

If its spinning on the starter motor but not firing you might want to check you have a spark. You can remove the plugs, reattach the leads and rest the body of body of the plug against the side of the engine block (to ground them). Spinning the engine on the starter, you should see the plugs firing even in daylight.

Sledge hit the nail on the head, if there's a clicking sound coming from the rear of the bike then the battery is flat. Charge it up or use a jumper pack to try and start the bike and see what happens.
Carby's aren't something any old joe can pull down a put back together, it takes experience and knowledge or you will f%$k them up, either that or you will put them back together with the same problems.
Keep us posted
Johno

Thank you so much for all the help! I plan to revisit the issue today/tonight and can definitely get the battery charged up @sledge. It very well could have been a rewiring issue (there were so many I wasn't familiar with) so when I walk back through it I'll check each one more thoroughly.

I know I left the diaphragms on when I sprayed the carbs (lack of knowledge on my part) so that could be it @mr72. It was set to "on" not "pri" though. The needle valve and seat was the only part I replaced in the carb as they were worn and the rest was clean.

As I haven't been back to it yet I haven't checked to see if it's getting fuel. Will keep you updated thanks again!

Have you a workshop manual?

May be a good move to get one 

you said the bike only has 3k on it, needles and seats dont wear out that fast so that change did nothing. the jets on the other hand could be plugged, especially the pilot jet as its the smallest. its the long one with the holes in the side. clean them all (3) and look through each to check with a light behind them, must be smooth and round inside. charge or replace battery as mentioned.