Boggs down when given throttle...please help.

[fxbrry]

I have a 1980 GS 850 that was given to me and has been sitting in a garage for 4 years. According to my uncle, the original owner, It ran fine when parked but now it only starts with full choke. It will onle idle but will not run without the choke. So today a pulled the carbs thinking they were gummed up but everything looked spotless and everything moved freely. I soaked it with carb cleaner and open and closed everything a few times to make sure nothing was sticking and reassembled it. I tried to start it and it cranked right up, with the choke. I eased the throttle a few times and got it to rev up. Where as before if I gave it throttle it would bog down and die. I let it warm up with the choke and took off in first gear with the choke still on. While going down the road and running through all gears it seemed to clean itself out and want to run, with the choke on. After a couple minutes of riding I was bale to turn the choke off and ride and it seemed to run normal in higher RPM's. The problem is that at around 1K to 3K RPM it wants to bog down and die without the choke. If you hold the throttle a few seconds it will finally kick in and take off and go. Here's the million dollar question...Does anyone know what could be the problem? It will not idle without the choke, even when It's warmed up. As a side note ( I dont think this makes a difference ) I removed the air filter since it was nasty and my new one has not arrived in the mail yet so I was running it without an air filter. I dont think this will make that much of a difference, at least it hasnt with dirt bikes I've owned in the past. I'm hoping that it will only take some running and riding so get everything cleaned out and freed up. Anyone have suggestions?

[TheCafeKid]

Running sans air filter will most certainly make a difference. Wait till your air filter comes in and then see how it runs, if its still bad..let us know :P

[Steve]

OK, you have at least two problems there:

1: carbs are still gummed up. Not sure how you "soaked the carbs", but if you did not take them completely apart and dip each carb in carb cleaner 'dip' for at least 24 hours, they are not yet clean. Click here to see the carb cleaning series that is in the Garage Section of this site.

2: you are trying to run without an air filter. Most dirt bikes of yesteryear did not have CV carbs, so you would have never noticed. The carbs on 1980 and later Suzuki GSs are Constant-Velocity (CV) carbs, which require, no, make that demand some sort of restriction on the intake tract to allow them to work right. I am surprised that you got anything above idle. :shock: For a quick test, you can tie-wrap a folded-over shop rag to the carb intakes. This is not accurate enough to do jetting checks, but the bike will run.

Until you get the carbs clean, tuned and synchronized, your bike will tend to be cold-blooded. Will almost always need half or more choke to start (cold). NEVER use any throttle to start the bike, it defeats the choke, making it very hard to start.

Before fine-tuning the carbs, you need to make sure the valves are adjusted. You can do a search on this site to find some excellent help on that subject, too.


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[mmarshall13098]

are you positive that all of the orifices are clean and open, especially the pilot jets (clogged pilot jets exhibit the symptoms that you are describing). air filters are critical...the carbs are "tuned" to run with the filter in place...removing this greatly changes the air/fuel mixture

[fxbrry]

Ok, thanks for the info guys. I thought that running without an air filter would affect the engine but wasnt sure how much. I should have my filter by next Saturday so I'll try this again when I have the filter in place. If that doesnt help then I guess I'll have someone that knows what their doing look at it. By the way, I didnt actually disassemble the carbs completely but I did take the carbs off the engine and upon inspection everything look spotless. I srayed them down really well with carb cleaner and made sure the buttlerfly valves were functioning properly. I didnt try to take the carbs apart since everything was so clean and working freely. I did removed the bottom caps and found that the floats were also spotless. I tried to remove the top caps but the screws were stuck and I didnt want to strip them so I left them in place. Can someone elaborate on what "pilot jets" are and what they do. I'm not too familiar with this. This bike will haul ass even when it's not running correctly. \\/ Thanks for the help.

[TheCafeKid]

Get yerself some PB Blaster and spray those top screws down...then read the carb cleaning section here on the GSR...learn it my man, you'll need to if you want to keep her running well. It's not that difficult to tear em down and clean em and put em back together....however i have found that balancing them afterwards is a different story...*sigh*

TCK

[rphillips]

Normally in carbs, it's not the moving parts that need attention. It's the little orafaces & passages that the fuel, air, & mixture need to pass thru properly. They are tiny. In a pilot jet, the opening is so small, you need to look close, just to see light thru it, tiny tiny. Like they said, the carb cleaning series on this site makes it pretty simple.

[Steve]

....however i have found that balancing them afterwards is a different story

The actual balance is not that difficult, it's just the fine-tuning of the mixture that takes time.

You (CafeKid) will see this when the rest of your parts come in. 8-[


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[mmarshall13098]

what ever you do...DO NOT be tempted to stick something into the jets to clean them...there are tools that you can buy to help clean the jets ($8-10) as for the pilot jet..i believe that someone already mentioned the carb clean series on this site..this is just a shot of the carb with the float bowl off. here you can see the pilot jet...take your time doing this and you will be fine

http://www.thegsresources.com/images...%20removed.jpg

[Johnny K]

Is your petcock hooked up properly? Make sure the hoses are hooked up. The small hole on the petcock is connected to the vent on the carb. I had the same problem and that fixed it.

[fxbrry]

Johnny K....I'm pretty sure the petcock is hooked up correctly. I reassembeled it the same way I took it apart but I dont know if it was hooked up correctly the first time. Can you explain a little more or maybe take a picture of the setup? There was a vent hose from the carb that hooked to the tank itself, a long vent hose that just dangles down and then two fuel lines that run from the carbs to the petcock on the tank. Stupid question...by petcock you mean the nozzel on the bottom of the bas tank where you select "on" or "res" ?

Thanks.

[Johnny K]

fxbrry, first of all there are no stupid questions at all. Trust me on that one. I am also a newb, and just wanted to add to that because it was the same problem I had as well. Unfortunately I don't have a pic to explain that. But these guys here are experts and without a doubt will help you in ANY situation that you come across as long as you tell them EXACTLY what is going on in that scenario. Sorry that I can't add to your question, just wanted to add input.

[KEITH KRAUSE]

Johnny K....I'm pretty sure the petcock is hooked up correctly. I reassembeled it the same way I took it apart but I dont know if it was hooked up correctly the first time. Can you explain a little more or maybe take a picture of the setup? There was a vent hose from the carb that hooked to the tank itself, a long vent hose that just dangles down and then two fuel lines that run from the carbs to the petcock on the tank. Stupid question...by petcock you mean the nozzel on the bottom of the bas tank where you select "on" or "res" ?

Thanks.

As others have said, it sounds like your pilot circuit is gummed up.
As for the tank to carb "vent" line you describe, the tanks fuel gauge uses an overflow line in case the gauge unit/gasket leaks. This way the fuel won't contact the engine. The line should just be run so that fuel will spill on the ground.
The two fuel lines from the petcock to carbs should actually be one fuel line, the larger one, and the other should be the vacuum line that should go to carb number 2.