OK, now for the run-down

[KRISTI'SGS550]

As some of you have already met me, but others have not, I will again introduce myself. My name is Cory and I am working on a 1981 GS550 for my wife. During college she had a 1997 CBR 600, but sold it when she was out of college. She missed bikes so much that I went out and found here this one. As far as I know everything on this bike is original, or orignial replacement parts.

When we picked the bike up it ran very well. Within a week the carbs began spilling gas. I tapped them with a screw driver and the gas problem ceased, the only way to start the bike was by using the choke. Before the carb spilling the gas problem the bike started without the choke pulled just fine. The bike began harder and harder to start and my wife decided she didn't want to ride it anymore, especially after it died on her going to work one day. I am not sure as to the details of this, she just called me and told me it died. I got off of work later that night, walked down to the bike, started it and rode it home. The bike had a little hesitation in the motor at this point. I let it "rest" and took it out the next day to hear it and ride it during the day. It started the same, rough and only with hte choke lever pulled. I rode it for about a half hour and it started sputtering. I walked/rode it home and found the front left corner of the cam cover was leaking oil.

I ordered the gasket for the cam cover and while waiting for the part to come I decided I would clean the carbs as well. I took the carbs off and cleaned them out; following a description I found on another motorcycle site. When the parts came I put everything back together and now the bike will not start at all.

I know one thing fore sure is the battery is dead. So I hooked the bike directly to a car battery, pulled the choke up and pushed the started button. The starter motor and everything electrical seems to be working great, no problems that I can tell here. The problem needs to be the spark plug, fuel system or air.vacuum. This is where I am confused. I am not sure where to begin or where to end with this one. I have been reading a lot of forums on here and have some good ideas on what I want to try, but I figured I would ask first and see if anyone has any ideas.

So does anyone have any ideas? I would like to get this bike running by summer for my wife. I want it to be reliable and want to spend as little money as possible.

I would like to buy a carb rebuild kit, new o-rings for the intake boots and a fuel petcock to begin with. Any other ideas/suggestions before I start?

Thanks in advance, sorry about the length of the post.

Cory

[psyguy]

on this site, you're most likely to hear the following:

strip and clean your carbs with new o rings (be meticulous)
check your petcock, may need replacing (not rebuilding)
make sure the air/fuel system is airtight, no leaks (be meticulous)
check/adjust the valves
check your coils
replace cables and caps (and new sparkplugs)

this is what you want to do on a bike of that age anyway, regardless of what particular part might the culprit at the moment

once you have all of the above done other possible faults are easy to find/diagnose as the esentials are sorted

have fun!

[psyguy]

I want it to be reliable and want to spend as little money as possible.

this may be difficult to achieve unless you can confirm that most parts are in really good shape and a few are obviously broken...

[KRISTI'SGS550]

this may be difficult to achieve unless you can confirm that most parts are in really good shape and a few are obviously broken...

I am sure all the parts are in great condition. Everything I have seen and touch is clean and seems to be working quite well and I don't think anything is broken, maybe just in need of some attention is all.

[psyguy]

The problem needs to be the spark plug, fuel system or air.vacuum.

yea, this pretty much covers everything i said... 8-[

anyhow, i'd start with confirming the spark
take the plugs off, plug them back into the leads, make sure they're grounded, crank the starter and see if you get a spark

[KRISTI'SGS550]

if the petcock seems clean and not damaged, but fuel doesn't flow from it to the carbs, would the first thing you check/clean be the carbs due to it being a vacuum system petcock?

[psyguy]

if the petcock seems clean and not damaged, but fuel doesn't flow from it to the carbs, would the first thing you check/clean be the carbs due to it being a vacuum system petcock?

what do you mean that the fuel doesn't flow?
try unpluging the fuel hose from the petcock and put a longer piece in its place, now suck a little to see if the fuel will flow (on "res" or "on" position)
try also the "prime" position - the fuel should flow constantly

also see that the vacuum line is not clogged, broken, kinked

[TheCafeKid]

my entirely not expert opinion. Check that there is no gas running thru the vaccum line of the petcock (the smaller hose) How to test? Put the carb end of it in your mouth and suck. Carefull (there are better ways to do this, such as a mightyvac or the like, but this will work, just dont swallow obviously) If gas is running thru that line, petcock is shot ( i would seriously suggest replacing it anyway, if you've ANY question at all about it. Sure its a lil pricey, but you wont have to for another 20 yrs)

Second, if you've got fuel spilling out of the overflows on the carbs, there are two possibilities i would consider, ONE, your float levels are screwed up, and TWO your float valves are bad. BOTH of which will require you to tear down the carbs, which you plan to do anyway...Since you're doing that, dont waste your money OR time with rebuild kits. They are often inferiour parts, incomplete and stupidly expensive for what they are. Instead, purchase some float bowl gaskets from www.z1enterprises.com and purchase a new carb and intake oring kit from www.cycleorings.com (while you're at it, i would suggest replacing the intake boot bolts with the stainless allen heads that are also offered on the cycleorings site, you'll need the rings for a set of BS type carbs and boots) Mr Robert Barr supplies the rings and bolts, great guy, super cheap, i think i have spent 30 bucks?? for TWO sets of the like.

Clean those puppies well. Cant stress this enough. Dont try to chinselmonkey out on it, or you will just become frustrated. Assure when you clean your carbs that your slide diaphrams have NO holes in them anywhere, not even a tiny lil pinhole. replace ALL the orings, assure ALL passages are clear, some people suggest removing all the rubber and plastic bits and soaking them in Berrymans or the like. Personally this is what i do, but there are varying opinions. Rinse the carbs well with water, blast all the passages out with air, assure your float levels are set correctly based on the factory specs, and reassemble.

I will also mention that it is imparitive that you inspect your valve clearances, and replace shims as needed as per your factory specs. And lastly and certainly NOT least, assure that your airbox fits tightly, and does not leak ANYWHERE. Air leaks are a common problem on these old girls, and carb balances are a tightwire act. The BS type carbs, from what ive read, as i personally have not had to deal with them much, are particularly intollerant of air leaks as they are vaccum operated rather than mechanically operated.

There are GREAT tutorials on this site, provided by other members on alot of the common proceedures. I do believe BassCliff has an excellent guide on valve adjustements, his bike is an 850, but as both his motor and yours are the Zook 8valve design, the proceedure is the same. And the GS Garage also has a great howto on the BS carb clean and rebuild.

Finally, dont give up, as much as you may get annoyed, as long as you press on, eventually, and fairly cheaply if all your other bits are in line, you'll get her running right.

Good luck!

[SqDancerLynn1]

The vacuum CV carbs NEED to be spotless & you need to change ALL the O rings. DId you reinstall the air box ???

[TheCafeKid]

One other thing i forgot to mention..important as well. If you've had fuel leaking like that, overflowing, likely its made its way into your crankcase. if your oil smells of gas, for certain it has. Change the oil and the filter, as the gas will wash your cylinder walls and cause serious damage over time.

[KRISTI'SGS550]

Clean those puppies well. Cant stress this enough. Dont try to chinselmonkey out on it, or you will just become frustrated. Assure when you clean your carbs that your slide diaphrams have NO holes in them anywhere, not even a tiny lil pinhole. replace ALL the orings, assure ALL passages are clear, some people suggest removing all the rubber and plastic bits and soaking them in Berrymans or the like. Personally this is what i do, but there are varying opinions. Rinse the carbs well with water, blast all the passages out with air, assure your float levels are set correctly based on the factory specs, and reassemble.

I wanted to get a kit because i am worried about the jets and the o-rings. Do you think though I can just clean the jets and replace the o-rings and be OK, if I do a great job? I am planing on buying the intake boots, screws and o-rings from Robert soon. I will add the carb o-rings as well.

Thanks for all of the great ideas! I will be trying all of this and keep you folks posted.

As with the petcock I will test it later and reply on how it reacts to the tests.

[KRISTI'SGS550]

The vacuum CV carbs NEED to be spotless & you need to change ALL the O rings. DId you reinstall the air box ???

I never took the airbox out. But on that subject. Would taking hte airbox out make taking the carbs out easier? These things are horrible to get out and even worse to get in. I fear I am going to damage me intake boots and air box tubes when reinstalling the carbs. Any tips, ideas or secerets to these things, anyone?

[psyguy]

I never took the airbox out. But on that subject. Would taking hte airbox out make taking the carbs out easier? These things are horrible to get out and even worse to get in. I fear I am going to damage me intake boots and air box tubes when reinstalling the carbs. Any tips, ideas or secerets to these things, anyone?

as long as all the rubber is as soft as it should be, you should have no problems, but do expect it to be time consuming.
i think you DO want to take the airbox off, makes the carb removal/replacement easier (IMHO)
you want to inspect the airbox anyway

[TheCafeKid]

I wanted to get a kit because i am worried about the jets and the o-rings. Do you think though I can just clean the jets and replace the o-rings and be OK, if I do a great job? I am planing on buying the intake boots, screws and o-rings from Robert soon. I will add the carb o-rings as well.

Thanks for all of the great ideas! I will be trying all of this and keep you folks posted.

As with the petcock I will test it later and reply on how it reacts to the tests.

The only prob you'd likely have w/ the jets is stripping them when taking them out for cleaning. They are made of brass, and rather soft compared to a steel screwdriver, so use a good fitting tool. Other than that, soaking them, and replacing the orings will do just fine.

[KRISTI'SGS550]

Thank-you both for the great ideas! When I have the carbs off for cleaning I will make sure to insect the boots for damage. Also I will order the o-ring kit and soak all the carb jets and carb bodies to clean all the jets, tunnels and passages. Then we will move to the valves, spark plugs, plug cables and so on.

Thanks again for all the help guys. I will return with more questions I am certain.