Hanging RPMs on '79 GS850

[Tanerrx]

I recently bought a '79 GS850 that had been sitting for about a year or so, from what the seller told me. I cleaned the carb and put a new battery in and the bike starts and runs. I took the air box off and cleaned out a bunch of rust that was clogging the air return from the engine. Now it seems to idle a little high and the rear left exhaust (your left when you're on the bike) is putting out a lot of white exhaust and popping a little. The main problem is the hanging RPMs. When I give the bike a little throttle it revs dangerously high and doesn't come down for 30 seconds or so.

What could be causing this? I'm guessing since I unclogged the air return that the mixture in the carbs isn't right.

[tkent02]

What could be causing this?

34 years of neglect. Time to get to work:

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

[Steve]

How did you "clean the carbs"?

If you did not totally disassemble them, dip them for 24 hours (each), then re-assemble with new o-rings and gaskets, you need to do it again.

But, what's causing your problem? A lean pilot mixture. Probably caused by clogged passages from the carbs sitting for a year.

.

[BassCliff]

Greetings and Salutations!!!

Hi Mr. Tanerrx,

With stock jetting in the carbs, these engines need a stock intake system too. If you remove the air filter or airbox, if there are leaks in the intake system, etc, it throws off the air/fuel mixture. A hanging idle is one of the symptoms of an air leak. These engines do not take kindly to running without the airbox UNLESS the carb jetting has been modified to account for the increased air flow. Most of the steps necessary for the care and feeding of your GS can be found in the links below. It's your "mega-welcome".

If you are here you probably have a 30 year old motorcycle that needs about 20 years worth of maintenance. In the links below you'll find maintenance lists, documentation, wiring diagrams, "how to" guides, vendor links, tips, tricks, and a whole lot of GS goodness. This is your "mega-welcome". Let's get started.

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!

More links to helpful threads in the forum:
Help! Your Bike Won't Start
DON'T DO THESE THINGS
Help! Your Bike Won't Run Well
Oh God! Pods!


Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

[Tanerrx]

Thanks

Thanks for the greetings and responses. I feel better now having a couple people help confirm my suspicions. I did take the carbs completely apart and sprayed some carb cleaner (Sea Foam I think) through the jets and any other little passages I could find. I'll have to redo it with the 24 hour soak and new o-rings and gaskets.

Does anyone know what the pilot screws should be set at on the carbs? I feel like they might have been moved by one of the previous owners to correct the mixture due to lack of air getting in because of the clogged passage that I spoke of in my original post, and now that I've cleared it up the screws are probably not set in the correct spots. I've checked the Clymer Manual for the bike but all I can find is that I'm not supposed to mess with the screws.

I'll read through my mega-welcome in the mean time to see if I can find anything in there.

[Big T]

Pilot air or pilot fuel?

Fuel (bottom) - 5/8 turn or so, look for a mark on the carb

Air (side) - 1 1/2 to start

Hanging idle means lean condition

[Tanerrx]

Thanks Big T. I've been trying to find that info for a while now. I was wondering about the fuel pilot screws on the bottom of the carb and it looks like someone has messed with them because they are more than 5/8 of a turn out.