When messing with my carbs today I decided to start the bike without the air box on, just to make sure slides weren't sticking.  When I did this I noticed that air and gas were coming OUT of the left carb. 

I'm guessing the only way this could happen is if the intake valve is not seating properly. 

Is this a symptom of simply neededing to check and shim the valves or could this be something much more serious (valve seal, etc)?

if it was a vapor thats normal (single carb) but sounds like they need to be balanced.
check the valve clearance but i think you will find it is fine.

check the vac tubes to the carb to be sure there pluged in right

vac tubes are fine and I've done the WD40 check for vac leaks

I figured it it was actually blowing out somewhat forcefully like it was it would have to be a leaky intank valve

Tis caused by a lean running condition. Or so I think.

So is that the answer then - just more carb tweaking? You guys don't seem too sure.

I agree with rangerbrown. A little bit of fuel/air mist coming out of the carb at idle isn't too unusual (although I haven't seen it on my GS), but the fact that it's only coming out of one carb indicates that the carbs are out of ballance or your intake valve has to little (or no) clearance from the cam.

First try ballancing the carbs, if that dosen't help or you are unable to get them to ballance, check your valve clearances. You may have a tight intake valve. It's easy to check your valves, all you need is a feeler gauge, but if you need to adjust it, you need to buy a $20 special tool. If the valves are tight, you can remove the shim and sand it down till the clearane is within spec instead of getting a new one.

It's not a valve thing, if there was no clearance at the gap it wouldnt run at all, or it would run but like complete ass. I'm going to say your a bit to lean on the bottom end. Carbs can be a little tricky to tune with no airbox.. try turning the mixture screw out a little bit, and sync'ing the carbs never hurts.
Do you normallt run the bike with an airbox on? When you say gas is coming out, is it pouring out? or does it come out like a puff of mist? and you can hear it pop?
If you normally run the bike with an airbox I wouldnt worry about it.

That is what happens if you have a turbocharger and very aggressive cams with lots of overlap... but I'd guess you have neither...

+1 on if it runs fine normally, not to worry about it

Haha - no turbo or agressive cams Lima.

I normally run with the air box. I've just had a lot of problems with the hanginging idle which it turns out was a result of the PO never replacing the covers on any of the vacuum inlets.  Carbs were still out of wack after i cleaned them so I've been adjusting float level and air screws trying to get them right. I was only running with it off to check slides.

Vapor was coming out, Gas was not pouring out -  that float is leaking a little but it was very slight as in a few drops a minute, Gas was coming out of one of the little holes on the airbox side of the venturi I dind't notice it till I pulled the airbox off and will attempt to adjust it tonight.

Bike runs great on the high end - idle is just junk still. I've fixed the hanging idle but now if I blip the throttle while idling the RPMs stumble and drop and sometimes the engine dies.  If i get the RPMS over about 4k before dropping the throttle its great and settles back fine.   I'll try adjusting or replacing the one float valve then playing with the mixutre screws to it running right under 4k RPMs

Guess I'll buy the stuff to make the $5 balancer and balance them while I'm at it. I sure hope she runs sweet after all the time I've been putting into this.   Oh well, I'm a noob so I guess this is sorta my initiation.

The carb balancer won't do you a bit of good if the valves are out of spec.  Make sure that everything else is right (valves, float height, new o-rings, clean jets, etc.) before you try balancing the carbs or you'll just end up frustrated and the bike still won't run right.

Hanging RPM's when you let off the throttle are also a symptom of lean air/fuel mixture. If I was a betting man I'd say thats your problem. Adjust the mixture screws out a bit, and see what happens.

I was hoping I could avoid having to tear into the valves until this winter when I'm back home and I can use my uncles giant, heated and fully stocked garage. I'm working in an apartment parking lot right now.

I was going to get the float issue sorted out and pull out the idle jets to clean them and then once the stubling revs at idle are taken care (hopefully just tweaking mix screws)  of I'd try balancing the carbs.

I rebuilt my carbs, adjusted my valves and changed my chain and sprockets in my apartment parking lot.

Seriously though, you can't balance the carburetors if everything else isn't right.  It's not that it's a bad idea.  It can't be done.  If the cylinders aren't running the same (at equivalent throttle), then the carbs won't balance.  You'll just throw it out of whack.

The best that you can hope for is to get them running evenly.  What I did was to take a spark tester and ground out one cylinder to a cooling fin while letting the other cylinder run the engine.  I switched cylinders, adjusting the balance screw until they were running at the same speed.  This worked best for me until I got my valves adjusted.

Would just pulling the cable off one of the plugs have the same effect?

 I had a Ninja 250 that did the same thing, valves were all very tight. The bike would rock with some of the backfires through the carb, not the safest feeling when you think about the airbox location.

Quote from: mjn12 on September 13, 2006, 01:11:29 PM
Would just pulling the cable off one of the plugs have the same effect?

It will, but it can cause....undesirable electrical failures.  As cheap as a spark tester is, and as costly as a coil is, and as much as you'll probably be running without the boot on the plug, go buy the $8 spark tester. 

So I've had the carbs back on all weekend. I've been riding but the problems not gone. The idle still climbs and once I go to get moving its a little unresponsive. I basically have to get the revs high, then let the throttle out to keep it from bogging down.  I did notice that the O ring on the little plastic 'L' shaped tube that is part of the float assembly was a little loose (it rotated freely).  Can anyone clue me in on whta the purpose of that is?

Can I get ahold of a rebuild kit for the '00 carbs? Will the rebuild kit that is marked for the 93's work for me?

I'll be checking the valve clearances this weekend once I get ahold of a feeler gauge so hopefully I can eliminate that as part of the problem.

Its not stopping me from riding but it makes me not trust the bike when I want to start moving and thats pretty scary wen I'm riding in heavy traffic.

Quote from: mjn12 on September 17, 2006, 04:45:02 PM
So I've had the carbs back on all weekend. I've been riding but the problems not gone. The idle still climbs and once I go to get moving its a little unresponsive. I basically have to get the revs high, then let the throttle out to keep it from bogging down.  I did notice that the O ring on the little plastic 'L' shaped tube that is part of the float assembly was a little loose (it rotated freely).  Can anyone clue me in on whta the purpose of that is?

Can I get ahold of a rebuild kit for the '00 carbs? Will the rebuild kit that is marked for the 93's work for me?

I'll be checking the valve clearances this weekend once I get ahold of a feeler gauge so hopefully I can eliminate that as part of the problem.

Its not stopping me from riding but it makes me not trust the bike when I want to start moving and thats pretty scary wen I'm riding in heavy traffic.

How were the valve clearances?

The rebuild kit will work.  See this post for details on it.  You need to replace all of the o-rings.  The ones on my 99 were completely broken down.  I doubt yours are any better.

I forget the purpose of that o-ring and the part it goes over. 

I'll be checking the valve clearances this week as soon as I get a chance. Since the bikes rideable its hard to tear it down with the great weather we're having this week.

Seems as though partsnmore is out of stock on the rebuild kits - any other good place to get them?

EDIT: Jets are on their way from the dealer, I had to buy in sets of four but the prices were almost as good as buying two seperately from sudco. If anyone wants a set of #40 pilots or #125 mains let me know. I'll sell for cost plus your desired shipping and any transaction charges (ie. paypal charge) If memory serves me right it was 10.xx for the 4 pilots and 15.xx for the mains (for the sets).

I'd like the pilot jets, I've been meaning to get them for a while now, but I'm lazy so I haven't. I'll send you a personal message with some details.

On a side note, the jets shouldn't have anything to do with your problem, but rebuilding and or cleaning the carbs isn't a bad idea, and I guess while you're in there you may as well do the jets, anyways good luck and talk to you soon.
Good luck