I need help getting an old 1977 Suzuki GS550 running. Can anyone help?

I’m trying to get this 1977 Suzuki GS550 I bought last year, running. A short history: When I purchased the bike, it was running, kind of rough, and started kind of hard. Ether was usually used if I remember correctly. So I thought I would take apart everything and give it a good cleaning. I have small engine experience from the military, so I’m fairly capable of projects like this one. I should have done a little better reading before I tackled this job because evidently, one of the jets was not supposed to be disturbed, it was set factory and I could not find a setting for it anywhere else.
I did trial and error for quite a while trying to get the carb settings right. I got pretty frustrated with the whole thing and shelved the project for about a year. I really want to get this thing running! I was Googleing stuff the other day and found an article someone wrote about turning all circuit screws out 2 turns as a starting point. That was the first solid thing I had found in a while. I tried it … and the bike started! Ran rough, when I tried to gas it it acted like it wanted to die. I let the bike sit for several hours. I went back out to crank it over and it started right up. Running rough, but started pretty easily. I turned the top screws on all 4 carbs out another half turn. Now each of those are set at 2 ½ turns out. It seemed to run a little smoother. I don’t have any gauges to check anything with.
I let it set over night. I came out in the morning to try and start it, nothing. I tried several times. I turned the 4 screws back the other way ½ turn. Now back to the original setting of 2 turns out. Cranking again, several more times. Still nothing. Ok. When I originally set all the circuit screws to 2 turns out, the bike started. Now, I have reset the screws from 2 ½ turns out to 2 turns out. Never adjusting the bottom 4 screws at all yet. Why won’t the bike run now?
Is it electrical? Last year when I was messing with everything, I also adjusted the points. One last thing I did just today, I did this with another bike I had many years ago and it worked like a charm, I put a couple tablespoons of STP cleaner in the tank to help clean the jets and things. My old bike ran like a scalded dog when I did this before! Are there any tricks I need to be aware of with these old Suzuki’s? I used to own Honda’s, Suzuki is all new to me. Can anyone help? I have included some photos.

I got it running again. Still rough though. The plugs were a little wet from over choking probably, so I cleaned them off and re gapped them. Started up. Now, I just think it's getting too much fuel. I not sure of the actual screw name but the one that controls the fuel inlet on the bowl of carb. I still have that set at 2 turns out as a base to start from. Have no gages. Do I lean it up now or allow more gas? 1/4 turn? If anyone knows the factory carb specs for this setting that would be awesome!

I'm not sure how much help I can offer other than to refer you to a Suzuki forum which includes a Suzuki motorcycle section . Go to www.suzukiforum.com
(http://www.suzukiforum.com)

Funny you posted this recently and I was at the stealership yesterday and they were working on an old 70's GS550! At any rate, I digress...

Looks like 2 turns seems to be pretty optimal as that's how you've gotten it running twice now. Playing with carbs in the past, I've found it best to just tinker, as the factory settings are more of a starting point. I didn't have much success with my Yamaha when trying to use the factory settings.

I would say to clean the exhaust outlet fairly well and run the bike at the 2 turns. See if you get any sort of residue - too rich will be sooty.

Any old bike, the key to getting them running, then running well, is making sure they aren't sucking air and aren't over/under fueling...

Easiest way to deal with this is to remove the carbs, then remove the intake boots that go to the head. If they are not fulla cracks and sucking all hella air at that age, I'd be very surprised. Nothing you do to it will make a damn bit of difference until this is dealt with, any float settings, idle mixture adjustments, etc will be meaningless.

Sometimes if the cracks are not too severe, you can get by for a while by pressing some RTV sealant into the cracks (from the outside) and kind of coat the entire exterior of the boots with RTV....it'll work for a while...and at least long enough to let you see how much of a difference it's gonna make, and how messed up your idle and mixture settings are now...because generally, someone's been idling it up and trying to richen the mix to compensate, not understanding what the actual problem is.

Then, while those carbs are off, take the bowl off of each and see how much crud is in them, the jets, emulsion tubes, etc. Get that crap outta there. Be careful not to bend the floats, but remove their pins and take out the float tip needles...they have a rubber tip that is supposed to allow them to stop the fuel flow when the float gets too high...usually they are shot, swelled, cracked, missing, something. Replace them. It's fairly cheap and easy, just drop new ones in. If the floats are foam type and all swelled or split, they're shot too. Will never work right. Replace and set float drop. If they are a pontoon type, hollow plastic or metal, make sure they don't feel like they have fuel inside them. If so, they're done.

Spray out the jets and tubes with carb cleaner, be careful because it WILL come out of someplace else, that's what you wanna see, but not as it shoots cleaner straight in your eyes...be aware of where the motor side of the carb is pointing...that's where it should exit from. If blocked, it's goona shoot straight back at the stick it's spraying from, so be ready for that too.

Take the tops off the carbs...I suggest loosening the screws, then spray the perimeter with WD-40...because under that cap is a diaphragm that is responsible for lifting the slide and needle...they will be brittle due to age, and if you rip one taking the cap off, you're buying new ones, and that includes the slide, and they are not cheap. Watch out for the springs, one on each slide, take things apart slowly so things don't jump out at you before you see how they went in.

See if the diaphragms are obviously split, if so, that carb will never respond to throttle. Also see that any compensating holes under the diaphragms are not blocked...that will make them refuse to move too. The slide should move easily up and down in the bore...if they are stuck, or gummy, gotta figure that out too or it'll never work right.

You can CAREFULLY peel the diaphragm away from the carb body (the WD-40 helps here too), and pull the slides and needles up and out, so you can see if they need cleaned. If corroded or varnished, clean them with some crocus cloth or Never-Dull, and the bore as well. They should slide up and down easily in there when you're done.

Once you got everything clean, replaced as needed, and put back together, it should be easier to get it to start and run so you can fine tune it. Carb synch is a whole nuther issue, but if you get this far, you're in the ballpark, it should run pretty good.

Couple of other things to keep in mind...when you fool with the points, you are not just changing points dwell, but usually shifting the timing, the way they are set up. There's an order to it that it needs to be done in, and I can't remember it at the moment. You need to get a manual for this thing.

Also I've seen several oldies like this that the points cam had gotten corroded, and rubbed the block off the points...so they failed to open or opened very little...again, clean with something just aggressive enough to remove corrosion without removing metal or scoring the surface. That lobe also needs lube. It'll wear out a new set of points quick without it.

Many times I've seen the ignition coils that looked great, but when you remove them so you can see the underside, they are literally exploded, cracked open and insulation hanging out...obviously, that's a problem. Amazingly, they will usually run, but on a humid day or a splash of water off the road, you're done for the day.

The plug wire end caps screw onto the wires...you can twist them off (counter clockwise) and trim off 1/4" of plug wire, clean up the little screw terminal in the cap, and twist them back on...that'll give you a much better contact there. Some dielectric grease would be nice too, if you wanna get fancy...makes them more weatherproof.

If it has a vacuum line to the petcock, make sure it's not split, chase it down to the source, if it sucks air it will interfere with fuel flow. Don't know if they used those that early though.

These are direct control carbs, no diaphragm.

Yes, disassemble and clean carbs.

Hasn't been mentioned, check for spark on all four.

Bike never ran good in this owner's experience, check compression.

If you want to campaign a 35 year old bike, serv ice manual is a must. I just saw Clymer for under $25 on E-bay.

Speediva "to clean the exhaust outlet fairly well " What does this mean?

These are direct control carbs, no diaphragm.



That's a good thing...old diaphragm carbs are always a problem....until you refit them with new parts...

Clean the very end of the exhaust pipes out - if it's running rich you'll get sooty black residue inside the exhaust pipes.

"if it's running rich you'll get sooty black residue inside the exhaust pipes. "

Ah - quick and easy diagnostic. No reason to clean this out tho', would you think? Won't interfere with breathing.

Do check point gap. Do check static timing.

I look at picture of air box and see no air filter. is there air filter? If not, you absolutely need to replace.

"if it's running rich you'll get sooty black residue inside the exhaust pipes. "

Ah - quick and easy diagnostic. No reason to clean this out tho', would you think? Won't interfere with breathing.

Do check point gap. Do check static timing.

I look at picture of air box and see no air filter. is there air filter? If not, you absolutely need to replace.

Wasn't the OP asking how to check to see if it really is running too rich?

<OP>I got it running again. Still rough though. The plugs were a little wet from over choking probably, so I cleaned them off and re gapped them. Started up. Now, I just think it's getting too much fuel.</OP>

It sounds as though the OP is unsure if it's rich or lean, so the classic residue test would at least eliminate rich if it's not getting the residue.

http://www.thegsresources.com/

try here there are a lot of good guys that will help. the gs have a bunch of known issues. the regulator rectifiers seem to be a week point on the bikes. they have a good trouble shooting paper for that.

since the bike is older, it uses points, the condenser will dry out over time. it is just a capacitor. mite as well change it with a new one. then do a electrical check. simple stuff like spark boots, wires and coil. see if you have any nicks scrapes or other damage from the years. one nice thing about the bike is parts are still around.