Hello again and sorry for bothering all, first off i've read through tens of forums so i come asking with some knowledge, I've opened my gs500 like a week ago to clean and sync the carbs(cleaned every single hole even the airscrew holes and put all thing of back in their place) ,change the shims since the one that were already in were so small not even the 0.02 would fit in and now they are in spec(0.07), change the oil from 10w40 to 20w50 since it was burning oil and i changed it to fully synthetic which only seems to make it burn more also changed the oil filter just the oil filter, cleaned the gas tank , applied an inline filter since it was really muddy still after being clean (no it is not the inline fuel filter i tried the same configuration with it on/off also not the fuel level i also blew air through the tap and the carb fuel intake just to make sure its not clogged) ,and changed the spark plugs and checked everything that means electrical ,fine blue sparks on both sides, the colours of the spark plugs however concerns me because ive been adjusting it so much today one spark plug is white the other is black and vice versa the next day . I think I ve opened and reopened the bike like 6 times now and I have had enough, i cant take it to a motorcycle mechanic because where i am living there are too few and the ones ive been to screwed me off ,now it is open and I won't open it ever again so I'm looking for some last fixed before selling it to the scrap yard ,one thing i've noticed is that this bike has been abused by the last owner, the kms have been resetted obviously and there is no petcock, literally, its just the fuel line straight from the fuel tank to the carbs, and even weirder its that it has been running amazing, with no fuel dripping or flooding the engine even after heavy usage all the past summer, until i decided to open it up to make all those modifications that is, at first the bike revved really bad but after adjusting the air screws that has been fixed, but now basically the air screws are almost loose and almost so the little cog that modifies the idle revving, i have tried backtracking to the original shims and everything thinking maybe thats the problem but same results , the bike also makes like a loud pop sometimes while revving it high ,it is not constant or consistent but its there from time to time , as stated in the subject, bike runs or used to run just fine the other day for like a few kms before it would just start losing power even at full throttle , then it would start to remain at only 60kms ,now after one minute or two if i ride that way and if i apply full throttle, with a really significant delay and some popping and shaking ,it would get way faster but again not for long, again this made me think its about fuel flow, the needles have no wear, gaskets also flexible and good, it maybe the float height because the only way for me to adjust it its by bending the small metal piece upon the needle rest on, i did not try the u-tube method because i could not find a clear tube that small around but will look more on monday, thinking of a rejetting but again because of my location, some 5$ main pilots would cost me 50$ with the shipping and im planning not to spend much more into this bike since i already had spent a lot so if drilling or anything like that is not a solution then im not really willing , i did not change the air filter just blew air in it, the intake boots are not cracked not even a bit and made sure the carbs are in nice and tight, the prev oner basically stuck the vaccuum hole in the carbs that should lead to the petcock with a hose and a bolt on it, again keep in mind, with all those bootleg modifications and improvements the bike was running really good for like 6000kms until i opened her up and started ''fixing it'' i should ve just stayed put and let it die on me who knows where.
   TLDR i dont know what to do anymore and im desperate and sick of it, i am going to take the carbs out for one last single time, any advice or tip is more than welcome.

while thinking of it,it may be just the float height, because i recall having that little metal part pretty close to the top, i did not actually measure it i just made sure both are set to the same level,if that small thing pushes more towards the needle is it running leaner or richer?

tho even if its just the float levels,i dont know how that solely exlplains the few minutes of the bike running just fine then just going crappy

TLDR - but are you losing a cylinder and is it an 89-00 spec bike ? If so, you may be losing a cylinder cos a trigger coil cut out from heat.
Cool.
Buddha.

Quote from: The Buddha on April 23, 2022, 03:28:34 PM
TLDR - but are you losing a cylinder and is it an 89-00 spec bike ? If so, you may be losing a cylinder cos a trigger coil cut out from heat.
Cool.
Buddha.

I doubt its electrical,i did not touch any coils or nothing until touching the carbs, again if i cruise that way at 60kmh for like 2 minutes and if i throttle it at max, it is delayed, it has popping sounds and its shaking but still speeding,but yeah could be

and yeah sorry it is a 2000 european model

OK 2000, Good Carbs I know very very very very well. As opposed to just very very well on the later ones.

Carb problems are related to throttle position. Not rpm.

Electrical problems are related to heat in that component, not rpm or throttle position or any of that nonense.

Engine problems are related to rpm and temperature and well, the other 2 problems.

Isolate it to what is the driving factor here., Diagnose and fix 1 problem at a time.

Cool.
Buddha.

I'd set the float height, remove the fuel filter, and wonder why the bike is OK without a petcock.

Quote from: Rallyfan on April 23, 2022, 08:25:24 PM
I'd set the float height, remove the fuel filter, and wonder why the bike is OK without a petcock.

once more,it ran amazing for almost a year now,not even a single spill or drop in power or anything at all without any petcock, i tried taking off/on the fuel filter and the issue its still the same, i will set the float height on monday and give an update then

update:now the left cylinder runs good but smoke is coming out of it like crazy,and the right one has no smoke but has such a big delay while throttling that it almost dies on me,literally if i just touch the throttle it would drop a few revs stay that way then it will rev up

Hi
Have you tried replacing the Diafragms in the top of the Carbs? These things can make the earlier carbs do all sorts of weird and wonderful things if they become worn and get holes in them. Take em out, hold them up to a light. carefully stretch them whilst looking for holes in the membrane. if any holes replace both at the same time.
Worth a try. Let us know how you get on.

i would love to do that but the shop that offers those oem parts currently has none in stock so i dont know what to do,thinking maybe finding a mechanic before i send the bike to a scrap yard

Quote from: Gibon on April 25, 2022, 12:43:51 PM
update:now the left cylinder runs good but smoke is coming out of it like crazy,and the right one has no smoke but has such a big delay while throttling that it almost dies on me,literally if i just touch the throttle it would drop a few revs stay that way then it will rev up

Did you end up checking the float heights? A tiny itty bitty adjustment makes a huge difference in how the bike runs. And float height is just a proxy measurement for fuel height, you have to check that with the tube method (carbs don't have to be on the bike but you must use petrol/gasoline).

I recommend using an actual float height gauge tool (they only cost like $15) but you can get by with calipers or even a standard ruler.

If the tab is bent towards the float needle then the fuel height will be lower (Leaner). If the tab is bent away from the float needle then the fuel height will be higher (richer). The goal is just to get it to factory spec. Then test the fuel height with a clear plastic hose. I think the fuel height is supposed to be just below the gasket surface.

Sorry I haven't messed with the float heights on a GS500 so I don't have the float or fuel height spec for your bike, maybe someone else does.

Open the oil dipstick and smell the crankcase. If you can smell gasoline then you're fuel height is too high or your float needle is letting fuel by (since you have no petcock you are relying 100% on the float needle to not dump gasoline into the engine.) If that's the case you will need to change the oil ASAP since the gasoline in the oil will destroy the bottom end of the engine.

It has to be something you did, since it ran fine before you opened up the carburetors. Carefully go through the carbs, check the the condition and correct placement of all the parts, and set everything to 100% stock settings. Don't get discouraged, its normal to have to take the carbs off many times to get a bike running right. I probably did it 10 times getting my GS1000 to run, and that thing has 4 carburetors.

anothe update:it most likelhy have been the float heights,im pretty sure they are in spec now since i was able to reach 150km/h and thats the fastest the bike ever went,sure it still has some odd things,like the left cylinder wont start by itself if the choke is not on and the left cylinder still has a little delayed throttle and does some popping but my bet its i just have to adjust the airscrews a few more maybe get a new sparkplug for the left cylinder and another coil for the right one,how many revs should each cylinder have individually at idle and if i dont see any outside spillings of gas around or below the carbs it can still drip gasoline into the engine?

Quote from: Bluesmudge on April 25, 2022, 03:47:19 PM

Quote from: Gibon on April 25, 2022, 12:43:51 PM
update:now the left cylinder runs good but smoke is coming out of it like crazy,and the right one has no smoke but has such a big delay while throttling that it almost dies on me,literally if i just touch the throttle it would drop a few revs stay that way then it will rev up

Did you end up checking the float heights? A tiny itty bitty adjustment makes a huge difference in how the bike runs. And float height is just a proxy measurement for fuel height, you have to check that with the tube method (carbs don't have to be on the bike but you must use petrol/gasoline).

I recommend using an actual float height gauge tool (they only cost like $15) but you can get by with calipers or even a standard ruler.

If the tab is bent towards the float needle then the fuel height will be lower (Leaner). If the tab is bent away from the float needle then the fuel height will be higher (richer). The goal is just to get it to factory spec. Then test the fuel height with a clear plastic hose. I think the fuel height is supposed to be just below the gasket surface.

Sorry I haven't messed with the float heights on a GS500 so I don't have the float or fuel height spec for your bike, maybe someone else does.

Open the oil dipstick and smell the crankcase. If you can smell gasoline then you're fuel height is too high or your float needle is letting fuel by (since you have no petcock you are relying 100% on the float needle to not dump gasoline into the engine.) If that's the case you will need to change the oil ASAP since the gasoline in the oil will destroy the bottom end of the engine.

It has to be something you did, since it ran fine before you opened up the carburetors. Carefully go through the carbs, check the the condition and correct placement of all the parts, and set everything to 100% stock settings. Don't get discouraged, its normal to have to take the carbs off many times to get a bike running right. I probably did it 10 times getting my GS1000 to run, and that thing has 4 carburetors.

i think before flooding into the engine it will also drip in the airbox correct?and that airbox has that small dripper that indicates that,correct?  i know because i just changed the oil one week ago because carbs overflooded,i think thats what happened, then i took out the carbs and bent it so high up that it had no more gas after a few minutes and now i think i got em in spec cuz its running way better than before,not perfect yet but still better, so the float heights were the issue all along, now i want to see if i can totally get it running amazing once again,ill fiddle with the airscrews and get that spark plug the following days and keep you updated

Quote from: Gibon on April 26, 2022, 11:45:37 AM
anothe update:it most likelhy have been the float heights,im pretty sure they are in spec now since i was able to reach 150km/h and thats the fastest the bike ever went,sure it still has some odd things,like the left cylinder wont start by itself if the choke is not on and the left cylinder still has a little delayed throttle and does some popping but my bet its i just have to adjust the airscrews a few more maybe get a new sparkplug for the left cylinder and another coil for the right one,how many revs should each cylinder have individually at idle and if i dont see any outside spillings of gas around or below the carbs it can still drip gasoline into the engine?

You may also need to synch the carbs - but yea air screws could also be off. Now ideally you want to set both air screws at the same # of turns out. If you have 2 equal cyl and the carbs are synched and floats are equal and everything else is equal, then as a last resort air screw can be a bit off else keep them at the same number of turns out left vs right.
Cool.
Buddha.

Quote from: The Buddha on April 27, 2022, 03:43:33 AM

Quote from: Gibon on April 26, 2022, 11:45:37 AM
anothe update:it most likelhy have been the float heights,im pretty sure they are in spec now since i was able to reach 150km/h and thats the fastest the bike ever went,sure it still has some odd things,like the left cylinder wont start by itself if the choke is not on and the left cylinder still has a little delayed throttle and does some popping but my bet its i just have to adjust the airscrews a few more maybe get a new sparkplug for the left cylinder and another coil for the right one,how many revs should each cylinder have individually at idle and if i dont see any outside spillings of gas around or below the carbs it can still drip gasoline into the engine?

You may also need to synch the carbs - but yea air screws could also be off. Now ideally you want to set both air screws at the same # of turns out. If you have 2 equal cyl and the carbs are synched and floats are equal and everything else is equal, then as a last resort air screw can be a bit off else keep them at the same number of turns out left vs right.
Cool.
Buddha.

there is something odd about the air screws now,no matter how much i turn them clockwise or counter nothing changes,i made sure the carbs were synced by the eye but i will visit a friend with a  gauge to sync them on thursday,any reasons why the air screws dont work anymore?or why the bike still stutters a little?

Synched by eye is actually better than synched by vacuum.
Now air screws have the habit of doing nothing, nothing, nothing, nothing and all of a sudden just taking it to the other extreme.
What is the issue you are trying to correct with air screw BTW everyhting else has to be absolutely spot on, remember jetting is best done WFO to shut throttle, not the other way around.
Cool.
Buddha.

Im having same problems. Im hoping my carbs come back fully serviced. I was cleaning the fuel tap and went on youtube to check what to do..... rust in tank ect.
i came across this (hope the link shows) https://youtu.be/jxItIFnjs0M
Im no expert and have only owned this bike a week or so.
Mine is a GS 500 E 1997
GOOD LUCK

Quote from: The Buddha on April 27, 2022, 09:54:53 AM
Synched by eye is actually better than synched by vacuum.
Now air screws have the habit of doing nothing, nothing, nothing, nothing and all of a sudden just taking it to the other extreme.
What is the issue you are trying to correct with air screw BTW everyhting else has to be absolutely spot on, remember jetting is best done WFO to shut throttle, not the other way around.
Cool.
Buddha.

left cylinder wont start and maintain rpm unless choke full almost on and right cylinder starts up without choke but has a delayed throttle and does some popping its really weird