GS850GL: Where to start to learn how to tune carbs?

[Guest]

I have a 1982 GS850GL. It was sitting for a couple years until a few months ago when I finally decided to get it back into working order.

I met a neighbor who is a mechanic. I took off the carburetors, he helped me clean them, I put them back on. He taught me about cleaning my gas tank with vinegar and sealing it with Red-Kote, which I did. I changed my oil. I changed the battery. I paid someone to fill / smooth dents in the tank and repaint it. I replaced the clutch cable (the reason the bike was grounded in the first place was a snapped clutch cable). I spent a bunch of time degreasing and scrubbing years of dirt and grime off every space I could reach.

Eventually, I got to a point that I was ready to start the bike. I could turn the engine, but it wouldn't start. I knew the carbs were full of gas. My mechanic neighbor taught me how to spray ether into the air box. That works. When the bike starts, with the choke open, it idles very high, around 3000 rpm. I can find a sweet spot in the choke that idles around 1200 while I let it warm up. No matter how long I wait, if I close the choke completely, it stalls.

I'm guessing the problem is that the carbs need to be tuned. I don't even know where to start with a job like that. I'm feeling a little lost without my mechanic neighbor, who got pulled away by a side job. I have the Haynes manual, but it honestly doesn't have enough pictures, context, or explanations for me. It's over my head. I have very little automotive experience. I've basically listed it all above, except that I've also changed my air filter once before. I tried reading through [this post](https://www.thegsresources.com/_for...our-Bike-Won-t-Run-Well&p=1659623#post1659623), and half the terms are Greek to me. Is there a course I can take somewhere to learn the basics? What should my first steps be? Thanks in advance.

 

[GSXR7ED]

I have a 1982 GS850GL. It was sitting for a couple years until a few months ago when I finally decided to get it back into working order.

I met a neighbor who is a mechanic. I took off the carburetors, he helped me clean them, I put them back on. He taught me about cleaning my gas tank with vinegar and sealing it with Red-Kote, which I did. I changed my oil. I changed the battery. I paid someone to fill / smooth dents in the tank and repaint it. I replaced the clutch cable (the reason the bike was grounded in the first place was a snapped clutch cable). I spent a bunch of time degreasing and scrubbing years of dirt and grime off every space I could reach.

Eventually, I got to a point that I was ready to start the bike. I could turn the engine, but it wouldn't start. I knew the carbs were full of gas. My mechanic neighbor taught me how to spray ether into the air box. That works. When the bike starts, with the choke open, it idles very high, around 3000 rpm. I can find a sweet spot in the choke that idles around 1200 while I let it warm up. No matter how long I wait, if I close the choke completely, it stalls.

I'm guessing the problem is that the carbs need to be tuned. I don't even know where to start with a job like that. I'm feeling a little lost without my mechanic neighbor, who got pulled away by a side job. I have the Haynes manual, but it honestly doesn't have enough pictures, context, or explanations for me. It's over my head. I have very little automotive experience. I've basically listed it all above, except that I've also changed my air filter once before. I tried reading through [this post](https://www.thegsresources.com/_for...our-Bike-Won-t-Run-Well&p=1659623#post1659623), and half the terms are Greek to me. Is there a course I can take somewhere to learn the basics? What should my first steps be? Thanks in advance.

I can't believe (yes, I can) I posted #10 on the attached link on 6/7/2013.

I bought a carb-tune a while back and even lent it to a member here and he returned it!

My accumulation is rather expanded...if and when I take inventory of all my "T" parts, boy will I be surprised!

Probably not...shaking my head...lol

Ed

****

 

[Nessism]

You might want to check the Newbie Mistakes link posted in my signature to see if anything applies.

 

[sacruickshank]

I have a 1982 GS850GL. It was sitting for a couple years until a few months ago when I finally decided to get it back into working order.
Eventually, I got to a point that I was ready to start the bike. I could turn the engine, but it wouldn't start. I knew the carbs were full of gas. My mechanic neighbor taught me how to spray ether into the air box. That works. When the bike starts, with the choke open, it idles very high, around 3000 rpm. I can find a sweet spot in the choke that idles around 1200 while I let it warm up. No matter how long I wait, if I close the choke completely, it stalls.

The Newbie Mistakes thread is certainly a good reference.

Given the info above describing behavior when closing the choke, the most likely issues are:
1. Idle circuit passages didn't get fully clean during the recent carb cleaning. Ultrasonic cleaning and compressed air are the best/only methods to clean and test for clear passages.
2. air/fuel mixture is wrong, either via air leak somewhere or mixture screw setting

 

[Guest]

How did you clean the carbs? Did you take everything apart and clean everything separately? Did you remove the jets and clean out the tiny holes in them and look at them in the light? I was in the same place that you are now in a dozen years ago and found it rather daunting at first. I dipped the carbs in Kleen flow carb cleaner for 24 hours and blew them out with a compressor. But they were still not good so I bought a sonic cleaner - try Harbour Freight, and Sharpertek carb cleaner that you mix with water - 85% water. There are other cleaning solutions on the market as well that are water based and not loaded with benzine and other chemicals. Could not believe the stuff that came out of them after half an hour in the sonic cleaner. I also bought a gasket kit and carb kit from Z1 enterprises just in case i needed another jet or part. Make sure that you use the right screwdriver for each jet, they are brass and if you use the wrong driver you can knacker the heads easily. There are some little passages deep inside the carbs that cannot be reached and I found the sonic cleaner was able to clean these. Study Bike Cliff's website - carb cleaning tutorial complete with pictures and step by step instructions. You might also want to change the O rings in metal flanges that are mounted to the engine. They get old and you can get air leaks here. Available at Z1.And a special nut driver with a screwdriver that goes through it for adjusting them when on the bike.

 

[Guest]

Carbs were definitely clean. Took everything apart. Cleaned everything separately. Ultrasonic bath. All done by my mechanic neighbor with decades of experience and all the right tools. I'm pretty confident it is not a problem of dirty carbs.

 

[Nessism]

Is the airbox installed?

 

[Guest]

Have the valves been checked/adjusted? VERY common problem with a non-start situation.

 

[650Skull]

Diaphragms in good condition??..............Holes in them also has the same syptoms

 

[sacruickshank]

A few more things to check in the long list ...

1. What is the setting for the air/fuel mixture screws? 2.5 turns out seems to be the norm for the Mikuni's on these bikes.
2. Are the intake rubbers and related orings in good condition? Still supple, no cracks, etc. If not, they may be letting excess air in, which is OK when you have extra fuel from the choke (if that's how choke works on these bikes), but too lean to run when there's no extra fuel.

 

[gustovh]

Try resetting your idle. With engine running turn idle knob until the rpm’s rise and shut off the choke. Then set to desired rpm.

V