I don't understand carbs one bit.

[Iarn]

So, a lot of things, here.

Hopefully, I don't come across as too ignorant.

I don't know any thing about how to operate or adjust these things. I don't know what I don't know, and that's an intimidating thing.

Part of the reason I got this bike is so I could have fun working on it and learn. However, working on these carbs has been a very frustrating experience for me. I'm a younger guy, so I've never got to have much hands on with carbs, on top of that, carbs seem to be going to way of the dodo these days and finding everyday examples to tinker on has been a challenge for me.

I've searched these forums, and read what I could but everyone is coming from such a place of experience when talking about carbs that it may as well be Greek.

First things first: could anyone provide some good resources on carbs for the inexperienced layman? I've searched and searched, yet I don't understand any of the material I've found.

Second, onto my issue: I just rejet my carbs to larger jets, in preparation for a K&N lunchbox filter and a 8" Delkevic exhaust.

It seemed like a simple enough procedure, even for a carb idiot like me.

Once I got the carbs removed, I unscrewed the four bolts securing the float bowl. I unscrewed the main and pilot jets and replaced them with the new larger jets. Checked gasket, soft and pliable. Put float bowl cover back on. Put carbs back on the bike. Re-hooked all the vacuum hoses, fuel lines, got throttle cables and choke cables perfect, put everything back the way it was. I adjusted nothing on the carbs, except the jets.

Now I see I have four tiny o-rings in this jet kit. Wtf is that for? I don't even know.

I install the lunchbox as it's simpler to re-install than the stock airbox. Still stock exhaust at this point.

So proceeding to attempt start, set frame petcock on PRIME for ~30 seconds. Set to ON and tried to crank, took quite a while. Maybe 20 or so seconds of intermittent cranking.

She starts, smells rich, to be expected. Idles at 1,200k or so for a split second then goes to 4,500k and sits there. Turn out idle adjustment screw all the way until it starts clicking. Now seems to idle at 3,500k.

So, now, here I am, don't know anything. And to the best of my knowledge I did this without adjusting anything else on the carbs beside the jets and she's acting wacky.

Is it the missing o-rings?

Will installing the exhaust fix that?

How bad did I mess up? Did I miss a lot of important things, or what?

[NYNJ8]

This thread is a great place to start: http://gstwins.com/gsboard/index.php?topic=56601.0

It is a sticky in the general discussions forum.  Don't give up, keep reading and tinkering.  Those who know how to diagnose and repair even minor carb issues are able to find really good deals on bikes when their owners give up and dump them.  I picked up my 06 GS for $1,100 because it had a dirty float bowl and an unseated needle.  The previous owner saw gas leaking from the airbox drain hose and was eager to dump it.

[Slack]

Your new exhaust may solve the issue. It depends on what size jets you just put in.
The thread by Ben, linked above, is your best friend!
These are the other pages I found helpful when learning carbs (I had previously had one experience tuning carbs on a bike 10 years prior. So I didn't really remember anything):
http://www.factorypro.com/tech_tuning_procedures/tuning_carbtune,CV,high_rpm_engines.html
http://www.gstwin.com/carb_work.htm
http://wiki.gstwins.com/index.php?n=Upgrades.Rejetting
http://gstwins.com/gsboard/index.php?topic=35237.0;topicseen

I would pick up a few sizes from http://www.jetsrus.com/a_jet_kit_street/suzuki_500_GS500E.htm# so you can get it tuned just right.

[Iarn]

Yeah, that thread by Ben2go  was great for learning the general bits of the carb.

Thanks for the links NYNJ8 and Slack. I still scratch my head when people talk about needles and turns and such. What does that mean? Are needles jets?

And I bought a jet kit from TheBuddha, he suggested 147.5 mains and 20 pilots for the K&N lunchbox and the aftermarket exhaust. Which is what I installed.

All I used from the kit was the 4 jets. It came with 8 bowl nuts and 4 o-rings, which I didn't use since I didn't know what they were for.

[Big Rich]

Where are you located Iarn? Some people learn best by reading, some learn by seeing, and some people need a person next to them to explain things.... you might be best at having somebody standing next to you explaining things.

I'll dig up some good carb / info sites I've found later (getting ready for work now). But when people refer to "the needle", it is the needle mounted to the slide inside the throat of the carb.

Edit: here's one link that explains carb function: http://www.dotheton.com/forum/index.php?topic=16745.0

[Iarn]

I live on the outskirts of Baton Rouge, LA.

Thanks for the resources, I've been and will be poring over them for a while. 

[Iarn]

Just did a more thorough warm-up on my Eleanor. She starts quickly now, immediately, without the choke. Where before I'd have to choke it and try once it twice to turn her over. She starts at about 1,100k RPM. When I turn the choke on, the tach needle will hit 5k from cold start. As the engine warms up, the RPMs rise. The problem gets worse. Once she's warmed up reasonably well, I turn off the choke and hovers at about 4k. Which is what my choke RPM used to be.

The RPMs also aren't very steady. You can hear and see on the tach that with the choke off at 4k RPMs the needle is going between about 4,000 and 4,300k RPMs, and it isn't very metered in how it stutters. Somewhat erratic.

[Slack]

Your running 2 main jet sizes to large right now.
K&N Lunchbox with stock exhaust uses a 142.5 main on most GS's.
You have 3 options:
1) install the right size jets for your current intake and exhaust set up
2) install the right exhaust for your current intake and jet set up
3) install the stock jets and intake until you can do 1 or 2

Did Buddha not send you any mid-main jets? 62.5 or 65?

[Iarn]

He did not include any mids. He seemed to be under the impression I didn't need them.

I can do #2 and see how she behaves then. I have the exhaust, just need to slip it on some time, when I have time.

I was thinking more to troubleshoot the problem before putting the aftermarket exhaust on, but if you think it'll improve the situation, I'm down to try it.

[Big Rich]

Iarn, what year is your bike again? I was unaware if you have later style carbs....

But the way your engine is revving up has me concerned. Either your idle is set very high, the throttle cable isn't fully returning, or you may have an air leak (which the orings in your OP may suggest).

[The Buddha]

O rings - may be to lift the needle on a 01+ bike - atleast in my kit it is, but I dont send 4, I only send 2. Past 2 ... its already too much.
Anyway, you have too big mains as slack pointed out. Pipe needed with your setup. K&N filter on a bike with a stock pipe is rather hard to jet right.
Cool.
Buddha.

[Slack]

Iarn: The carbs need to be tuned to what is currently on your bike. You can't "pretune" your carbs for a modification your going to do in the future. Rejetting doesn't add power, it can only optimize the power the engine would have already been generating if it was jetted properly.  As Rich stated you may have some throttle or choke cable issue; But you won't know for sure until you aren't pouring extra gas into the engine by using jets that are too large for your current setup. All that extra fuel could be the only problem you have.

K&N filter on a bike with a stock pipe is rather hard to jet right.

20/65/142.5 

[Iarn]

Iarn, what year is your bike again? I was unaware if you have later style carbs....

But the way your engine is revving up has me concerned. Either your idle is set very high, the throttle cable isn't fully returning, or you may have an air leak (which the orings in your OP may suggest).

2004 GS500F

O rings - may be to lift the needle on a 01+ bike - atleast in my kit it is, but I dont send 4, I only send 2. Past 2 ... its already too much.
Anyway, you have too big mains as slack pointed out. Pipe needed with your setup. K&N filter on a bike with a stock pipe is rather hard to jet right.
Cool.
Buddha.

I finally know what those do, thanks!

Iarn: The carbs need to be tuned to what is currently on your bike. You can't "pretune" your carbs for a modification your going to do in the future. Rejetting doesn't add power, it can only optimize the power the engine would have already been generating if it was jetted properly.  As Rich stated you may have some throttle or choke cable issue; But you won't know for sure until you aren't pouring extra gas into the engine by using jets that are too large for your current setup. All that extra fuel could be the only problem you have.

K&N filter on a bike with a stock pipe is rather hard to jet right.

20/65/142.5 

I see, so the concept of pre-tuning is a mistake in this regard. Thanks. I'll install the exhaust in the next few days and see what comes of it.

[The Buddha]

The pre-tuning - LOL is a new word - if you were eventually going to install K&N and pipe - you can just swap the pilot drill out the caps on the air screws set it to 3, and leave all the rest stock. But the 147.5 mains needs K&N and pipe. I dont usually put in 2 sets of O rings though. I must have done that just to confuse you.
Cool.
Buddha.

[Iarn]

I'm actually working on the pipe installation as this is being written. If quality permits, I'll be posting some sound comparison videos of the exhausts.

I'll also report back with any problems after the install.

[Iarn]

Okay, new exhaust is on, in addition to the K&N Lunchbox. No apparent change in behavior. I rode it around the neighborhood to warm it up and hear the new sound, and the idle maxed at about 5.6k.

The exhaust didn't fix the issue. She's warmed up right now, I'm going to take a vid of the tach. I think it's acting slightly erratic, but i'm not sure.

In 1st gear, warmed up, zero throttle input from me. Bike likes to sit at about 4900RPM under load. When I pull in the clutch, it rises to about 5600RPM

ALERT: Loud droning bike at 5.6k RPMS. Here's a minute of it idling. No choke. No throttle.

[The Buddha]

OK pipe and K&N are in, and 147.5 mains and 20 pilots and 1 of those O rings and 3 turns out on mix screw
OK you could have an air leak, or a hanging cable ... or - well after eliminating all that - try 3.5 or 4 turns out. 3 is just a starting point per se. People adjust it winter to summer sometimes.
Cool.
Buddha.

[Iarn]

Whoa whoa whoa. WHOA. Slow down there cowboy. What's this about 1 o-ring and mix screws? Nobody mentioned anything to me about that.  The only thing I altered on the carbs were the jets. I've altered nothing else. 

[The Buddha]

Yeaaaayyyy I am a cowboy. I always thought I was an Injun ...

Ok the O ring is under the e clip on the needle. It will lift it up about 1mm.
The air screw set to 3 - well ... its the formula. Its independent of the air filter/pipe. You set that to where it runs best. Its mostly idle and low rpm control.

Cool.
Buddha.

[Slack]

Yeaaaayyyy I am a cowboy. I always thought I was an Injun ...

Does the engine speed change as you turn the bars? Higher to the left or right?
That would indicate either the throttle or choke cable being out of adjustment.
Try disconnecting the throttle cables and start the bike to see if the problem persists.
You can normally hear the hissing from an intake leak if that's what's causing it. Use a piece of hose as a stethoscope: put one end in your ear and the other near the carb boots.