Idle @ 5500 RPM

[Rotten1]

I traded a Tippmann A-5 paintball gun for my new project, GS850 (G?). It was not running when I got it, and had been pretty cut up by the PO. The exhaust was chopped and there were no pods on it when I got it to run and the idle was way high.

I know that due to the open exhaust and the lack of filters the bike would run weird, so, I did the following:

1. cleaned the carbs.
2. purchased and installed Dynojet Stage 3 kit
3. purchased and installed PODs

I started the bike today and reinstalled the tach to see the the RPMs and I am running at an idle @ 5500 RPMs. I adjusted the air screw up from 4.5 turns (DJ settings) to 0 turns with no change.

I am using a coke bottle to feed the carbs fuel as I am not yet finished with the tank installation. (modifying a GS550 to fit the GS850 Frame).

In trying to let the carbs run out of gas, I removed the coke bottle, and added vacuum (via my mouth) to the fuel hose and the idle dropped as I sucked back, inversely if I blow into the fuel supply hose the RPMs raise above the 5500 RPM.

Would not using the tank with a petcock valve cause the high RPM?

Thanks

[old_skool]

Well....at least your taking one already cut up and trying to resurrect it, How did you clean the carbs, you have to do a full tear down and dip them, install all new o-rings, or your wasting your time, and no advice will help, Your going to have your hands full trying to get it to run right simply because you have no baseline to go from, it was already missing most of the exhaust, you may want to add mufflers at least till you get it running decent, then you will be playing with jets and everything else with those carbs, your going to have them off and on many more times to get them right, be patient, and wait for the guys who have done this more than once to chime in.

[mike_of_bbg]

Welcome; first post I see. Things I'd look for if I'm idling high (you said it was idling high before you did work on it, so we'll say there was a problem already):

Idle adjustment up too high (duh).

Choke plungers stuck open. These bikes will run high with the choke on as the cylinders warm up.

Throttle cable tightness (should be ~1mm play when closed).

Obvious vacuum leaks (capping the petcock vacuum line? All sync port plugs in and tight?).

Intake boot condition and o-rings.

Did you check the sync when you cleaned the carbs? Is your 850 a 79 model or later (79 should be VM carbs, 80 and later had CV type carbs)? I know on the CVs that you can leave throttles hanging open if one is too far closed relative to the others. The petcock vacuum tap will by on cylinder #2 for CVs, #3 for VMs.

I believe that all 850s are G's - a G being shaft drive, though they may also be GLs, which would be a shaft drive "cruiser".

There are carb rebuild guides and a wealth of other information on BassCliff's site:

http://members.dslextreme.com/users/bikecliff/

[BassCliff]

Greetings and Salutations!!

Hi Mr. Rotten1,

Proceed through the maintenance lists in your "mega-welcome". Know that if you skip any steps or take any shortcuts you may be leaving you and your bike vulnerable to catastrophic failure.

Let me dump a TON of information on you and share some GS lovin'.

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", "Top 15 Tips For GS Happiness", the Carb Cleanup Series, and the Stator Papers. All of these tasks must be addressed in order to have a safe, reliable machine. This is what NOT to do: Top 10 Newbie Mistakes. 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

[TKGS750L]

idle

Rotten,

In addition to the other advise, the vacuum hose should be closed while not attached to the tank. The suck, blow thing I dont know about but it not being closed off will cause the engine to run funny. But, first things first, you will need to install an exhaust system or most if not all your hard work will have to repeated more than necessary. Once you have the exhaust installed here are some things that have happened to me:

1. The clutch cable can lay in a position that does not allow the throttle assembly to fully release(usually without the guard).
2. The interior intake boot clamp-screws can do the same thing.

My main concern is the lack of effectiveness of the idle screw this is what leads me to believe you may have something externally wrong with the carbs. If and when you have adjustment then you can begin to fine tune.
Good Luck!

[Rotten1]

Thank you all for the quick replies.

After reviewing the Carb rebuild guide there was a step that I missed in removing the cylinder that the needle slides into and clean the holes in the side. So I will start over on the carb rebuild following the guide to a tee.

Today I will also remove the intake boots and replace the o-rings to make sure there are no leaks.

I got the exhaust re-installed and should have a opportunity to fire it back up to see if the new o-rings and carb rebuild has helped.

Now that I know that the bike runs and the electrical is sound, I can focus all the attention to the carb issues.

[MisterCinders]

Looks like an L. Tkent likes to work on these with a flamethrower. I think you will end up with a sexy ride though.

[Rotten1]

UPDATE:

I finished the second carb rebuild, replaced the o-rings in the intake boots, reinstalled the carbs and fired it up.

I believe that the issues were a bit of all the possible solutions stated above. Thank you again.

The bike is now running and idling. I am going to have to do quite a bit of research on how the jets/air screw/needle all work together in tuning the bike.

Right now I have the Dynojet Stage 3 w/ 165 main jet, however, I had to dial back the air screw to 2.5 turns instead of the 4.5 that DJ recommended. I am sure that all of this will have to change after I get the bike in a riding state with the gas tank mounted and finding a seat.

I will be searching the forums for the tuning information to learn how all these jets work and correspond.

[TKGS750L]

carbs

If you were to describe your running issues(symptoms), or lack there of, it may be possible for someone to help with suggestions.