OK, so I've posted a few times before thanks to everyone for their help), but I am still having problems with my bike (I've had it for 2 weeks and still haven't ridden!!).  I apologize in advance for the novel I have written...

Problems -- bike starts (after a few tries), but won't stay idling.  It dies after a few short minutes (even with the choke full on).  I can keep it idling if i stay on the throttle, but when I let it off it dies.  There's also a bit of 'popping' from the exhaust when I give it gas.  Today, after being extremely frustrated with just looking at it in the garage, i attempted to take it for a ride around the block.  I actually rode it to the street, but when I turned the corner and gave it gas it simply sputtered and died.  This happened several times while trying to make it around the block.  So...she's in no shape to be riding around.

What I've done -- after my first search through the posts, I cleaned the carbs and made sure my hoses were going to the right place.  I've also got some new jets coming in a few days which I'll put in.
After a few more searches -- attempted to 'reset' the air/mixture screws to keep it idling (my bike was missing one of those screws when I first got it).  When all the way in, should the screws be even?  It seems that the screw on the rt carb goes in deeper than the one on the left.  Also attempted setting the idle screw while the bike was warm...no luck.
More searching -- checked float height and all seems to be OK, but I'm going to check again
Still searching -- replaced spark plugs.  checked plugs after running bike, and the left one seems to be getting carbon fouled.  This means I'm running too rich so I should back out the screw, correct?
Another search -- did wd40 test, and my bike never revved up
Final searches -- looks like I need to do a vaccum test to synch the carbs, check the coils, and possibly do a valve adjustment...uggghhh. 

Have I missed anything?  Do you guys/gals think that the main culprit is just finding the right setting for all those screws (Idle and pilot)? 

While the vaccum test looks easy to perform, I don't know if I want to spend the time and money to make the device, and I don't think I want to buy a multimeter and attempt fixing electrical stuff on my bike.  I figure if I can't get it working by now, it's time to bite the bullet and take it in to the shop. 

Please help with any advice!!!!!!

Have you checked to make sure you have good spark on both sides?
Carbon fouling means either you're running rich or the cylinder is misfiring.
... and no, turning out the mixture screw makes it more rich.  Your mixture screws should be turned out the same on both sides.  To make sure they're at the same position simply turn both screws in until you feel some resistance (don't overtighten!) then count the number of turns out.
Just make sure you have good spark on your left side before you get into further diagnosis.  If you've got a misfire, your bike will definitely run like crap.  Even a slight misfire will cause the sparkplug to become fouled and will then misfire more and more as the carbon builds up on the plug.

Making the differential manometer is cheap.  Like, $6.00 and a block of wood.  

However, you should adjust your valves before balancing your carbs will do much good.  It's easy, especially if you watch Kerry's video.

Your idle screws should go in approximately the same amount (mine are about 1/4 turn different full in with new o-rings), but you have a new o-ring on one, so that will probably affect it.  They should be about 3 turns out or so.  

If your bike runs with you giving it throttle, turn the idle screw in until it will stay running.  

Quote from: Recreational_Anxiety on August 10, 2006, 10:11:07 AM
Have you checked to make sure you have good spark on both sides?
Carbon fouling means either you're running rich or the cylinder is misfiring.
... and no, turning out the mixture screw makes it more rich.  Your mixture screws should be turned out the same on both sides.  To make sure they're at the same position simply turn both screws in until you feel some resistance (don't overtighten!) then count the number of turns out.
Just make sure you have good spark on your left side before you get into further diagnosis.  If you've got a misfire, your bike will definitely run like crap.  Even a slight misfire will cause the sparkplug to become fouled and will then misfire more and more as the carbon builds up on the plug.

going to check spark right now...will report back.  thanks!

checked for spark, and both looked good...as far as i could tell.  i have noticed (when i cleaned out the carbs) that the vaccum hose is a little/lot bent (as in almost folded) coming out of the carb.  would this affect it at all?  i'm going to search around to see what size hose that is...but if anyone knows please post.  i think i'm going to replace it with a longer one.

The vacuum hose coming from the carbs opperates the petcock when it's set to On/Res.  If it were pinched off, you'd get little to no fuel.  An easy way to check this is just set it to Pri.

I'd say check you valves.  If you take your time, it's easy enough to do yourself.  At the very least, buy/borrow a compression tester from Walmart or an autoparts store and check your compression.  It's super easy to do and only takes a couple minutes.

thanks guys.  i thought about the vacuum tube...and it made sense.  (duh)  the bike still acts the same way - either in prime or on.  i just tried riding it around again, and same problems.  i can lay on the throttle and it just kinda sputters and has no power.  i tried adjusting the mix screws but no luck.  it seems like she wants to go but the 'power' just isn't getting there.  also continues to die when you hit the brakes.
is this a compression problem? 

It could very well be... things like sputtering and loss of power are syptoms of a loss in compression.  It's really just part of basic troubleshooting though; you need 3 things to make an engine run: fuel, spark, and compression, a problem with any of them can cause problems like you describe.  Also, compression is probably the easiest to check, but also the most overlooked.

You just bought this bike right?  Do you have any idea what the previous owner might have done to it?  For all you know the carbs have the wrong size jets and it'll never run right.  Your absolute first step is to buy / borrow a compression tester and make sure the rings / valves are in decent condition.  If you find that one or both cylinders has low/no compression your only option is a rebuild.  Hopefully that's not the case though.  I would go through the carbs again and make sure that every o-ring is in place, intact, and undamaged; including the little ones under the top cap and the large one on the plastic slide support.  Unscrew the jets and use a magnifying glass to read the sizes engraved on the side.  Reset the pilot screws to 2 1/2 turns out.  Make sure the float valves are set properly using the clear tube test.  Throw in some new plugs and make sure you have a fat, blue spark on both sides.  At least it starts and runs, that's more than I can say for my bike when I bought it.

-M

i'm heading to autozone right now to 'rent' a compression tester and will post my findings.  i do have new jets on the way, so i'll be in those carbs again...replacing what i can.  i'm bummed because i just got my new jacket in the mail (brockton cycles has some good closout deals) and i was hoping to ride around with it. 
mandres -- i guess i should be happy that it starts, and i can at least cruise around in my parking garage at 10mph for a few turns before she cuts out!  maybe i'll just be the coolest guy riding around in the parking garage...

so i finally got the compression tester...and i wasn't sure how to work it (give me a break...i'm new at this).  so, i did my best to figure it out.  took out one plug, started the bike, pressed the tester on the hole (the screw in threads were too big to fit) and held it there with manly force and rolled on the throttle.  got 3 readings around 60...but i think the bike was kinda cold.

then moved to the other side (the left), removed sparkplug and tried to start...and nothing.  it worked on the right side...but now no start.  is this a symptom of something or is it normal???  am i even doing this right?  i'm going to search around. 

please post with any input!

It needs to actually screw in the plug hole to get an accurate reading.  There are adapters available to fit the threads.  Alternatively you could do it the old fashioned way by removing the plug, grounding it on the cooling fins and holding your thumb over the plug hole while you crank it over.  The compression should blow your thumb off the hole. 

i'll give the thumb check a go.  but even without the sparkplug (fully removed) in the right the bike started right up.  when i took the left one out and tried to start, no go.  does that narrow it down to anything?

The right side isn't running.  You should be able to confirm this by holding your hands on either side of the engine's cooling fins.  The running side will get hot, the non-running side will be lukewarm at best.  You can also use the exhaust pipes for this, but don't get burned.

As far as what this means, you still need to figure out the problem.  You need fuel, air, compression, and spark for the engine to run.  Figure out which one(s) you're not getting correctly, fix that, and problem solved.

so i went down again and ran my bike (basically idled it revving the throttle) and felt the fins on the engine.  maybe it's subliminal, but the left side feels much warmer than the right.  the right side is getting warm, though.  it's just that it feels the left is much warmer.  the rt side may have gotten warmer given more time, but in 5 mins i was still able to keep my hand on it longer than the left side.  hmmmmm....

It will get warm, but not hot.  There is friction, heat carrying over from the other side, and it may be running somewhat, but you must find out why that cylinder won't run. 

Oh, and for future reference, check the compression with both spark plugs removed (and grounded on the engine!) so that it doesn't start. 

cool.  thanks!  i'm gonna check the battery ground wire in a bit (i read that it could cause problems), then call it quits for the night.  ugh...so frustrating. 
one more frustrating coincidence regarding Mandres' post: "You just bought this bike right?  Do you have any idea what the previous owner might have done to it?"...as i was searching for help and answers i ran across this --
http://gstwins.com/gsboard/index.php?topic=27241.msg287735#msg287735
dude...this is the guy i bought the bike from.  small gs500 world in san diego, huh?  oh well...maybe i can make progress where he couldn't!

Yea, that guy goes by PrincessofDiablo on another forum I read.  I've been trying to help him fix the bike for the last month but he's pretty much a dumbass.  Sorry you got stuck with his problems. 

let's go back to basic!
did you check the air filter clean or not?

i did a visual check on the air filter (didn't take it out), and it does look clean.  not brand new, but clean...