Carb issues

[anesbitt267]

So I'm very inexperienced with carbs need some help guys. My bike when I got it wasn't running very well. Rpm's would get stuck and no matter the temperature out I needed to full choke to start and let it warm up for a long time to ride it. I messed with every possible thing before taking the carb off. I accidentally replaced mid jet with main jet and it ran a bit better actually but was too rich and still had issues. So I took carb off again and replaced all jets. (Besides needle jet i think I can't find it). I believe it's the needle seat and tang that goes in it is replaced. Jet needle replaced but not sure if it's adjusted right. Now the bike starts up once again only on full choke and if I take choke off it dies along with a really bad up and down idle. Occasionally getting stuck at 3k+ rpm. Basically runs worse now and I'm at a loss with it. If anyone can help out I'd appreciate it.


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[The Buddha]

OMG - I dont think I even understand this stream of consciousness description of yours.

Jet Needle does not have a seat. It should not be changed - thank god for you it wasn't available.
Seat and needle should seal up, and if they do that, you're good.

I can sort it and jet to your setup if you send to me. So this is an 01+ I presume - Yea I have the jets for it. You should have while in there swapped to a 20 pilot, a 132.5 mains (if stock) lifted the jet needle, made sure floats are closing right - yes that's the seat, the O ring and the needle that gets pushed in with that tang, and synched the carbs by eyeball. Which I will do for $50 and return shipping. You in US right. Else shipping will kill ya and take forever and all sorts of nightmare.

Cool.
Buddha.

[Bluesmudge]

With stock jetting, the bike should require choke to start and run for the first 5 minutes. Once its been ridden around for 5 minutes you should be able to take the choke off. It sounds like it was running better to start with.

Since it sounds like you don't know what you are talking about with carbs, I would take The Buddha up on his offer. I think he gets a better deal on Jets than you or I can just ordering a few or one rebuild kit. At the $50 he is charging you aren't spending much more than you would on just the parts for a carb rebuild. JestRUs charges like $7 per jet so with 3 jet per carb that's $42 before you even factor in the price for new gasket and o-rings or shipping.

[mr72]

didn't you guys notice this dude's dismissive reaction to input before?

Hey OP, any new problems you are having are all due to the work you did on the carbs. The original problem is that you didn't know how to work the choke, and then you didn't know how to receive help from people who have more experience than you. Even if Buddha fixes your carbs perfectly, you're still going to have to learn to use the choke.

[Bluesmudge]

mr72, I didn't realize this was the same person I've helped before. Unless someone hangs out here for awhile I don't recognize screen names.

I just went through OP's post history and realized I've already spent way too much time giving them the same advice multiple times and they are the one to tell us that "a bike shouldn't start in the cold at 4K."

Ummm, ok that's exactly what the bike should do. So I'm done here too. OP, If you want help go read our old posts where we gave you all the info you need or just send your carbs to the Buddha. In the end though, the bike should start in the cold or hot weather at 4k - 5k until its been ridden for a few minutes. The Buddha's jetting will probably shorten the time you need the choke because he prioritizes easy starting vs fuel efficiency. If you want the bike to start cold without choke your idle circuit will be too rich for the other 99% of the time you aren't starting the bike and you will be wasting fuel. If you don't like this advice and don't want to learn how carbs work then just go buy a fuel injected bike.

[mr72]

Yeah BS, I only noticed because I came to this thread thinking, "hey, I can probably help with 'carb issues'" and then wondered why the OP was already on my ignore list.

[anesbitt267]

didn't you guys notice this dude's dismissive reaction to input before?

Hey OP, any new problems you are having are all due to the work you did on the carbs. The original problem is that you didn't know how to work the choke, and then you didn't know how to receive help from people who have more experience than you. Even if Buddha fixes your carbs perfectly, you're still going to have to learn to use the choke.

I've actually did everything you guys told me too. You've all been a lot of help I just don't think I know how to describe the issue. I understand the choke and all the other stuff but the bike just isn't right. Kinda new to everything so I sound very stupid but I have tried just about everything. Maybe it's a vacuum leak somewhere I don't know. But I can't get the bikes mixture right it seems.


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[chris900f]

Well, apparently you have an iPhone, so make a video of your start-up procedure/issues, upload it to YouTube and post it here.

[Bluesmudge]

Man, I have a problem: I'm still posting here.

One thing that is clearly confusing OP is that there are two "needles" in most carbs. There is the needle jet needle, which has the sharp thing down the middle that actually looks like a needle and that goes into an emulsion tube. Then there is the float needle, which looks nothing like a needle to me but its the thing dangling off the floats that seals the bowl when the floats rise. Based on the confusing first post here, I'm not sure which one was messed with.

The jet needle never really needs to be replaced unless there is damage for some reason. Some "carb rebuild kits" come with a replacement jet needle but its usually of worse quality than the OEM needle and shouldn't be used unless you have visible damage to your OEM needle. Dyno jet also sells different needles but you shouldn't use those unless you are taking your bike to someplace with a dynometer to measure air/fuel ratio across the rev range to get the dyno jet kit set up correctly (that's what I did, and my bike runs amazing). Dyno jet kit without a dynometer = too many variables to get it running right.

Unless I am mistaken because of how confusing the first post in this thread is, all of the current "issues" are related to the bike's idle so there is no reason to be messing with the mid jet or main jet or needle jet. The only things that effect idle are the idle jet, the idle speed screw, carb balance, mixture screw, and float height. Vacuum leaks and float needle leaks can also effect idle, but since you "actually did everything you guys told me too," then a vacuum or float leak is unlikely with everything already replaced since you must have set the carb back to stock and  replaced all the rubber parts related to the airbox boots, carb o-rings and gaskets, and intake boots/o-rings, like I told you to do, so a vacuum leak is very unlikely unless you put something back together wrong. Go over everything you did when replacing all those things to look for something that was put on wrong.

I'll still stand by my previous posts in your other threads:

Smelling rich is normal with the choke on. The choke adds fuel (or chokes air) to make the mixture more rich for cold starts.

It kind of sounds like the previous owner bumped up the idle speed to mask another carb issue.  Maybe the pilot jet is clogged in one of the carbs but not the other. Unless you are saying the rpms bounce like that when the bike is cold with full choke, that sounds more like maybe a vacuum leak. The previous owner may still have been masking it because the bike will be less effected by carb issues when its fully warmed up. This is why its important when buying a used bike to always make sure a bike is dead cold before starting it for the first time. Feel the headers to be sure the previous owner hasn't warmed it up before you get there. A lot of issues are only noticeable during the warm-up period. That said, the GS500 is cold blooded, especially with factory jetting. With stock jetting it should require full choke for a minute or two when cold. Even if the ambient temperature is high. The entire GS series is that way. My GS1000 will never start cold without full choke.

You will need to start doing some diagnostic work. Its a 16 year old carbureted bike with an unknown history, so you are going to have to get comfortable working on carburetors and replacing rubber parts related to fuel and air. It could be a combination of issues which is difficult to diagnose (like old fuel or rust in tank plus vacuum leak). My strategy when I buy an old carbureted bike is to pull the carbs and replace everything rubber related to fuel and air and make sure all the jetting and carb settings are stock or +1 from stock if the bike is known to be lean from the factory like the GS500. Then adjust the valves. Then vacuum sync the carburetors. I throw is fresh spark plugs for good measure. That combination should get any bike with good compression running great. If the valves are out of spec and the carbs aren't in sync, that's hard to diagnose. Best to just do all these routine maintenance items all at once to set the bike back to "new."

I can't remember, what year is your GS500? Unless its relatively new, its probably due for new carb-to-head boots and o-rings.


One other, but less likely, possibility: Check the carb's CV diaphragm to see if it has any damage or pinholes. Damage to that diaphragm can make the throttle slide misbehave.

I will also add that its normal when getting a new-to-you but old and non-running bike back to a running state to have to pull the carbs 5 or 10 times to try things or find out what you didn't do correctly. Especially on multi-cylinder bikes. There are a ton of variables and they all have to be perfect or nearly perfect. Maybe you replaced all the jets and float needle but when you put the carbs back on and check the fuel height you then find out that you messed up the float height in the process of putting the floats back on. Totally normal and easy to do, you just have to try again. Float height is just a proxy measurement for fuel height, so even if you check the float height with the carb apart its best to check the fuel height with gas in the carb using the clear tube method. Fuel should rise in the tube to just below the float bowl gasket surface, if that's true your floats are set correct. You have to check both carbs.

I guess what I am saying is, you shouldn't come posting here every time something goes wrong because we are just going to send you back to the garage to pull the carbs again and check everything which you could have just done yourself. Its best if you spend some time on the internet learning how carbs work, especially CV carbs so you actually know what you are doing to your bike. Because at the moment you don't know enough to help us help you. You have to learn what all the parts are actually called and what they do so that you can actually describe the problem. If you don't like all that, send your carbs to The Buddha! Then you can just slap them back on to your freshly replaced carb and intake boots, connect the freshly replaced vacuum and fuel lines, and be done.

[sledge]

The first thing anyone who knows about BST33`s, I mean.....REALLY....... knows about BST33`s will say is.........

"Are the slides worn"

They will then say.............

"Because if they are......you are wasting your time trying to set it up"



https://store.moto-lab.com/articles/bst33-slide-guide-wear-indicators