Carb vent lines

[FlyingSteve]

If the 2 vent lines are facing down and sitting by the swingarm, could that cause an issue with the carbs leaking fuel out or idle issues?

Other than those 2 vent lines and the 1 vacuum line for the petcock, are there any other hoses/vacuum spots??

[Calvin Blackmore]

model and year will be required for the specific parts of your questions.

[FlyingSteve]

Right then, 80 GS550E

I should say the issue... When I bought the bike, it idled with no issue. After I got it, I stripped it down, cleaned some parts up, etc... Nothing major. I took one of the carb float bowls off to see the size of the main and pilot jet.
I didn't screw with anything else and I put the carb bowl back on. Today I finally got the bike all back together and after I started it up, I noticed fuel leaking from the one carb and I think it may have been the one I took apart.
So I started to take the airbox and everything out and when I pulled the plastic box off, some fuel spilled out... Well, I started the bike back up again and this time the carb didn't leak any fuel.

However, it will idle with the choke pulled up a little bit but if I try to close the choke, it dies. If I hold the throttle open a little bit, it will stay running with the choke closed. I'm thinking vac leak, maybe on one of the carb boots, since I did remove them from the engine... But I was curious if those 2 vent lines could cause issues because they are facing down and the hoses run down to the swing arm.

[Dave8338]

Idle issues may be related to the fuel dripping out. Both are likely related to the petcock. As for the routing of the lines, they are supposed to be draped up on over the stock air box. Do you still have yours in place?

The only other lines that I can think of are the valve cover breather and the vent line for the fuel gauge if you have one.

OK, I see that you DO have the stock air box, GOOD...this will make things a lot easier to fix. Have you pulled the carbs apart, soaked them and put things back together with all new orings.

[Calvin Blackmore]

AHA

Ok so the carb vents I doubt would cause a problem
I cannot speak of the other vaccuum oroented lines as I do not have that model but there is a manual at basscliff's website.

http://www.mtsac.edu/~cliff/storage/gs/GS550_77-82_all.pdf

that would save you an opinion from soeone who may have a modded setup but are unaware of the fact.

[FlyingSteve]

Eh the petcock works fine. I have the stock airbox but I am 2 curse words away from throwing it in the trash and getting pods. I'm so effin annoyed with how stupid the whole airbox setup is and how much crap you have to go through to get to the damn carbs.

Only other thing I can come up with is that I put the megaphone exhaust on... It is a 4-2 exhaust but I would imagine it flows slightly better than stock... Also the left side muffler is not on... As in it isn't connected to the crossover pipe. But I doubt that would cause this big of an issue with the idle.

[BassCliff]

Greetings and Salutations!!

Hi Mr. FlyingSteve,

I believe I have yet to offer you a "mega-welcome", containing a couple of task lists which will usher you into GS nirvana if you take no shortcuts. Let's get to it...

I just stopped by to welcome you to the forum in my own, special way.

If there's anything you'd like to know about the Suzuki GS model bikes, and most others actually, you've come to the right place. There's a lot of knowledge and experience here in the community. Come on in and let me say "HOoooowwwDY!"....

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", the Carb Rebuild Series, and the Stator Papers. Now let me roll out the welcome mat for you...

Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

[Calvin Blackmore]

Eh the petcock works fine. I have the stock airbox but I am 2 curse words away from throwing it in the trash and getting pods. I'm so effin annoyed with how stupid the whole airbox setup is and how much crap you have to go through to get to the damn carbs.

Only other thing I can come up with is that I put the megaphone exhaust on... It is a 4-2 exhaust but I would imagine it flows slightly better than stock... Also the left side muffler is not on... As in it isn't connected to the crossover pipe. But I doubt that would cause this big of an issue with the idle.

it would most assuredly cause a massive problem with idle.

[Suzuki_Don]

All air intake and exhaust must be completely sealed. These GS motors are very susceptible to air leaks of any kind. Seal the airbox, intake boots (both from airbox and to engine) and hook those exhausts up properly.

[FlyingSteve]

Well before I monkey with anything else, I will reconnect the original exhaust system and see what happens. I suspect that maybe the carb intake boot o-rings, at least one of them might be leaking but I'm going to see about the simple stupid things first. Sealing the airbox shouldn't matter... The only thing that should affect the carbs would be an air leak after the carburetor. But I put the airbox back together as it was before when it ran fine.

[tkent02]

Sealing the airbox shouldn't matter... The only thing that should affect the carbs would be an air leak after the carburetor.

Sealing the airbox matters a lot.
The airflow restriction is what calibrates the carbs, it has to be right for it to run well at all.

[FlyingSteve]

Can I put like a K&N cone filter on the end of the plastic air box or will that still screw it up pretty bad?

[BassCliff]

Hi,

From your "mega-welcome":

***********Quoted from Mr. bwringer************
Every GS850 [and most other models] has (or had) a set of well-known issues that MUST be addressed before you have a solid baseline for further troubleshooting. It's a vintage bike, and it's quite common (as in, every single GS850 I have had contact with) that there are multiple problems that have crept up and slowly gotten worse over the years. It's not like a newer vehicle, where there's generally one problem at a time.

These common issues are:

1. Intake O-rings (install NEW OEM or Viton only - common nitrile O-rings will quickly deteriorate from heat)
2. Intake Boots (install NEW -- these cannot be repaired)
3. Valve clearances (more important than most people think)
4. Carb/airbox boots
5. Airbox sealing
6. Air filter sealing
7. Petcock (install a NEW one)
8. On '79 models, install new points or Dyna electronic ignition (or at least verify that the old points are working correctly)
9. On all models, it's fairly common to have problems with the spark plug caps. These are $3 or $4 each, and often worth replacing if you're keeping the stock coils/wires.
10. Stock exhaust with NO leaks or holes -- good seals at the head and at the junctions underneath.

What I have noticed at the rallies is that very, very few 850Gs are actually running right. Make VERY sure it's actually running the way it's supposed to before busting out the modifications.

Brian's E-Z and fun plan for GS850 happiness:

1) Seal the airbox and air filter with weatherstripping.

2) Ensure no intake leaks. Spraying WD-40 or water doesn't tell you much, since very small air leaks can cause problems even though they won't suck in enough WD-40 to make a difference. Replace your intake boot o-rings and boots if needed, and seriously consider spending the lousy $28 for new airbox/carb boots.

3) Ensure clean carbs with correct settings, new o-rings, and original OEM jets. No, not just squirted with something. I mean completely disassembled.

4) Check/adjust valve clearances (Manual calls for every 4,000 miles. This is not optional.)

5) Ensure healthy electrical system.

6) Seriously consider upgrading coils and plug wires.

7) Install new, stock NGK B8-ES plugs gapped to .031".

8 ) Fine-tune float height and idle mixture screw to ensure best off-idle transition.

9) Clean air filter and reinstall with only the lightest oil mist -- over-oiling and/or letting the filter get dirty is a common and critical mistake, and will make the bike run funny at low speeds and run rich. This may take a few tries.

10) Make sure the exhaust seals are sealing.

11) Ooh, much better now, huh? You're gonna need upgraded suspension - Progressive or better fork springs and shocks. Set suspension sag appropriately.

12) Upgrade brakes with new pads and stainless lines to deal with all that extra speed.

13) Install new petcock, since I'm going to head to the roof with a rifle if I have to read about yet another #2 plug fouling and failed hillbilly attempts to rebuild the petcock and/or deny there's a problem.

14) Oh yeah -- check compression somewhere in there to ensure the valves and rings are reasonably healthy.

15) You'll probably need new OEM clutch springs -- the clutches last forever, but the springs get tired after 20 years or so under pressure. E-Z and cheap.

Carburetor maintenance:

Replace the intake boot o-rings, and possibly the intake boots. Here's the procedure:

http://bwringer.com/gs/intakeorings.html

Here's an overview of what happens with this particular problem:

http://cycleorings.com/intake.html

You'll also want to examine the boots between the carbs and the airbox. There's a good chance these are OK, but check them over.
And finally, if things still aren't exactly right, you'll want to order a set of o-rings for BS carbs from the GS owner's best friend, Robert Barr:
http://cycleorings.com
Once you receive these rare rings of delight, then you'll want to thoroughly clean and rebuild your carburetors. Here are step-by-step instructions that make this simple:
http://thegsresources.com/gs_carbrebuild.htm
--------------------------------------------------


You've got a 30 year old motorcycle there and it needs some TLC. If you don't do it right and just donky-donk around with it, you will never get it to run properly. Most of these classic GS bikes run best (and most reliably) in their stock configurations. Clean the carbs properly, adjust the valves, seal the airbox and the rest of the air intake system, etc. Do it all correctly. Period. Otherwise you will be continually frustrated.



I can't say it any plainer than that. Do it the right way, the first time, and you won't have to worry about it for another 20 years or so. Keep us informed.




Thank you for your indulgence,


BassCliff

[Steve]

Can I put like a K&N cone filter on the end of the plastic air box or will that still screw it up pretty bad?

I don't know what is "like" a K&N cone filter, but yes, you can put one on. Just be aware that you will then have to re-jet the carbs to get things to get anywhere near "normal".

Actually, changing the exhaust will probably require re-jetting to some extent, but going to pod filters will require even more changes.

The biggest advantage of pod filters is that it is easier to remove the carbs. However, the only reason you will have to remove the carbs after the somewhat mandatory full cleaning regimen is to keep trying to re-jet the carbs for the pod filters. If your tolerance for frustration is rather high, go ahead with the pods.

.

[Danjal]

The carb vents can cause fuel to leak. While the needle valve is more then likely the suspect in the type of problem it causes Ive had it happen. As fuel moves out of the bowls it creates a vacuum, and it sucks in some air from the vent to compensate. If you plug that up it creates more vacuum and hasw no way to relieve it besides suck more fuel in through the needle valve. Pretty soon it starts flooding the carb with fuel and just starts letting it roll out the jet. My 85 GS550ES spewed fuel out the idle jet intakes and ran the RPM's up to 4-5k... just dripping merrily away. The vents were linked between the 2 carbs. If you plug up a vent with debris im sure it could do the exact same problem. All you need to do is pull the hose off and make sure you can blow air through it. As little fuel that flows throughone of these it wouldnt take too much air to displace the vac that is in the bowls. SO remove the lines if you suspect blocked vents and just blow in them. If you get air..its non issue unless you can see a visable kink in the line. Just check and move on.