My gs is troubling me. Background, sat in a garage for 3 yearsts , "fully" drained of gas. I replaced the battery and threw some gas in it, fired right up.

Idle hovered and it hesitated when reved

Tore the carbs apart, cleaned everything and put new stock jets in b/c the ones in it were messed up(the screwdriver slots were partially stripped). Added one #4 washer under the needle. Fired right up. hesitation was gone. at first idle was great. then it started hovering again. Also the revs don't go up with the choke on until I rev the throttle. tested with some spray and seemed like one if the boots wasn't sealing. used some rtv and fixed that. idle still hovered. tested with sray again, no difference. messed with idle screws. everything from 3 turns to 6 makes no difference. tested with spray again, seemed like other boot was leaking. rtv fixed that but idle still hovers. tested with spray yet again. idle changes sometimes when I spray near the choke. not consistently though. I can see a few very small cracks in the rubber around on of the carbs choke slide. I'm confused though. if it were pulling air, wouldn't spraying carb cleaner always bring the idle down?

I'm temted to throw some 40 jets in it but I'm just afraid its just going to mask an issue?
Oh yeah, valves have been checked and clearances are all within range.
Thanks in advance for any help. I'm excited to bring this bike back from the graveyard but a bit frustrated with it at the moment....
Nate

I'd just replace the carb boots if they're dry rotting or cracking. Any vacuum leak will cause it to run lean and cause idle hover issues. I'm assuming it was lean, as it evened out when you put the choke on. Another thing to check would be the carb vacuum lines and fuel lines. If it's been sitting for 3 years, some of the lines could be rotting away as well.

All fuel lines have been replaced. Carb boots aren't cracked. The oring around the choke slide has a few small cracks, but spraying around there doesnt change idle...

How about the vacuum ports on the carbs? I think one of them should have a cap on it, and the other one connected to the T. I know there was a post around here somewhere with a buttload of carb information...

EDIT: Not the post I was looking for, but this may help:
http://wiki.gstwins.com/index.php?n=Main.HoseRouting

Did you completely clean the fuel passage ways that lead to the main inlet in the carbs? Gunk will hide in there, and needs some serious air to get it out. Note: not the fuel lines, the metal passage ways.

Fuel passage to air screws likely culprit. It could clean itself out in a few miles ...
You could open the air screws a bit more ... 3 turns is a good starting point ...
Cool.
Buddha.

i cleaned the snot out of the carbs. all passages seemed to be open. I went through the carbs again today, everything seems fine inside, but same behavior. I even replaced the vacuum hose, and double checked all the vacuum ports, everything seems tight and sealed. I opened the air screws up, 4-6 turns didn't make a bit of difference.

Any ideas??

Well, if the carbs seem fine, and it's not a vacuum leak, perhaps the issue lies with the petcock? It may be gummed up, causing fuel starvation and a lean condition. I'd check the tank vents as well.

I will try just running a hose to the carbs directly and seeing what happens. I won't have time to mess with it again until Wednesday, but at this point, I'll try anything.
I am running it with the tank off using a funnel and some spare gas line at the moment so the tank vents shouldn't matter, but I will definitely make sure they are clear before reinstalling the tank.
Thanks

I'm really not sure how much this could play a role with your current setup from a funnel... but... I remember adidasguy posting about how he found out that an auxiliary/temporary fuel tank/supply did need to be placed at the relative height of the stock tank to achieve proper fuel delivery.  His setup was the motion pro temporary fuel container and lines.  If placed too high, the fuel would overflow the carbs with known good floats, needles, etc... Can't remember if too low had starvation issues or if he encountered that, but I would guess it could have that effect depending on the setup... 

- Bboy

The funnel is basically at the height of the front part of the tank and up. It doesn't come out the overflow so I know its not too high, but I could raise it and see if that matters....thanks for the ideas....
Nate

Funnel - or sometimes the ahem ... less redneckier amongst us use a coolant reservoir off a water cooled bike ... anyway can be @ the mirrot height or so, I hang it off there ... anything from 1" to 1' above the carbs works fine ... obviously your bike runs on a full tank to all the way down to empty ...
Cool.
Buddha.

Just curious,
When I checked the valve clearance, the exhaust side was just barely over the bottom limit of the clearance range, like .04
Could that cause my idle issues? I read on here that valves should be the first thing checked, and I did, but having never owned a GS, I didn't know if being that close to the bottom limit would cause issues since it is still technically in range?
Thanks
Nate

Ok. So I have proper valve clearances, ran the bike with fuel piped directly to carbs from a funnel. Same idle woes. Even though the slides operate appropriately, could the o ring for the slides guides be bad? I've ordered some #40 pilot jets.... as a kind of hail Mary maybe it'll help/ work.

Aha!  A similar problem to one I've been having on my '07 GSF!  Here's what I found and and figure:

Up front, check your vacuum lines for integrity thoroughly.  They're really picky. I had a tiny leak at the 'T' junction.  The bike would do nothing but idle.  You could take the throttle to the max and it didn't make a bit of difference.  Even on the petcock's 'Prime' position.

What happened in my case was I had my gas tank fall off while inspecting all the lines (it was full...my fault).  I had a real my mama of a time figuring out where everything went, INCLUDING having referred to the diagrammatic on this site.

Bottom line currently is that, while the bike does run well (at 26K Km.), it drips gas through the overflow tube when parked.  Maybe 250cc over 24H. Problem is...the overflow tube comes out of the bottom of the air cleaner box.  Now how does that happen?

Meanwhile and backgroundwise?  I've been riding bikes for 47 years, got a million miles under my rubber (yup), and was a mechanic before the word 'technician' came into use.  This is now an official case of 'TMI'.

So, again, check out that damned vacuum system and ask yourself what the hell was wrong with the old idea of "ON, OFF, RESERVE'.

Ted Dentay
Mount Albert, ON
Canada

PS  If you have any brilliant insights please drop me a personal note as I'm not on this site until I run into trouble.  Shame, eh?

This bike only has one vacuum line, from the Left carb vacuum side port to the petcock. I replaced the line, so I don't think its leaking. There isn't an overflow hose on it at the moment. And that shouldn't effect it idling. I will double check my one line but I can't see it making a difference as I have capped the port and run with the funnel with the same results. Also, spraying wd-40 around its connections doesn't change a thing. Thanks for the ideas.
Nate

Quote from: natnov on July 23, 2013, 06:24:39 AM
Just curious,
When I checked the valve clearance, the exhaust side was just barely over the bottom limit of the clearance range, like .04
Could that cause my idle issues? I read on here that valves should be the first thing checked, and I did, but having never owned a GS, I didn't know if being that close to the bottom limit would cause issues since it is still technically in range?
Thanks
Nate

A valve going tight and on the verge of doing so, if that is the only issue it has - will start up perfectly and run for about 5 sec, and right there it will stall.
Sit there and rev it to 4-5k, and do it till it comes up to full temp, and it will run great till you shut it off.

Cool.
Srinath.

Swapped keys to 40s now won't run with coke, have to give it throttle to stay, once warm it runs great, but idle hands at 3-5k I'm lost

Can you adjust it with the idle adjustment screw? Have you checked your carb boots for leaks?

Can adjust with idle screw, but only up and it takes a ton our turns to go up. Boys don't leak according to wd-40 anyway....