82 Gs550l Headache

[deerejohn]

I am very frustrated with the way my Suzuki runs and I cant figure it out. First, off the choke has to be just right when running cold. Too much choke and it races at 4000 rpm. Not enough and it stalls. Furthermore, when it starts to warm up I have to adjust the choke down as the rpm's start to increase and it starts to race. I don't know if this is normal or not for these bikes.

The bike seems to be very cold blooded, as I have to let it warm up for about 5 minutes before I take off on a 70 degree day, then it still seems to bo sluggish on the low end when driving. Once I get going and drive it for another 5 minutes, then it seems to run better.

The major probem it has is with the idle. The bike will rarely idle on its own and when I turn the large idle knob it doesn't seem to change much. After I adjust the knob and road test it, the idle races. I then trun the knob to back off the idle and it runs great at 1100 rpm for about 30 seconds and then tarts to stumble and finally dies. I have tweaked the knob so may times that I can't get it right. There has to be something I am missing. Please help!

Here are some details on the bike:

I bought it in non running condition with 5800 miles from a local dealer.
I completely cleaned the carbs twice and replaced all the orings
I replaced the intake boots and have no intake leaks
I set the idle pilot screw to 3 turns out from seated
The gas tank is clean and a new petcock kit was installed
An inline fuel filter from he tank to to the carbs was installed

[Nessism]

The part about cleaning the carbs twice has me wondering, why twice? Are you sure they are clean? Did you take them apart and dip them? Take out the pilot jets, pilot screws, spray all the orifices out with carb cleaner spray after soaking in the dip? Air filter condition?

[deerejohn]

I had this running problem after the first carb clean so I did it again to make sure. I cleaned all orifices. I have rebuilt many carbs in the past so this was nothing new to me. I dipped it and used compressed air and carb cleaner to clean each passage. As far as the the air filter goes, I would say that it is in ok condition. I can't see anything wrong with it.

[Nessism]

Sorry for all the bad luck.

The symptoms you describe sound like carb problems. Since you are experienced with carbs, I'm at a loss regarding what to suggest.\

EDIT: Went back and reread your post. It's normal for the idle to race like crazy with the choke. It's also normal for the bike to be cold blooded, although not to the extent you describe. Adjusting the pilot screws to 3 turns out is about right for the 550 so you may want to try that if you haven't already. Also, syncing the carbs might help if you have not already done that. Shimming the needles helps with cold bloodedness as well so consider that if the other stuff doesn't work.

Good luck.

[Outlander]

I am no expert here. I just rebuilt my carbs as well. My choke use to work, and when it did, I had the same issue. Bike would scream, and I had to let the choke down to about 2 grand, and let her idle there. Soon after, I could disengage the choke, and she would idle.

I wonder, though, if your float settings are right. Maybe you got to much fuel going in, or not enough? Did you bench sync your carbs? Once I did that, my bike run a lot smoother. Just some ideas.

Check your plugs, see what colors they are. Maybe one is richer than the others, or to lean etc. May help diagnose a problem.

[deerejohn]

I understand the proper way to sync these carbs is with a manometer, but howndo you bench sync them.

[Nessism]

Bench sync is when you verifying the butterfly's are all open the same using a piece of wire as a feeler gauge. Shouldn't be necessary unless you messed with the sync adjusters when the carbs were apart - go straight for the vacuum gauges.

[cconsultpa]

mine does the same thing

My brother got me a 82 gs550l with a kerker exhaust. even with a rejet on all 4 carbs this bike acts exactly the same way. The bike however screams on the highway. My new problem is the 100 jets love the fuel and I need to find a bigger tank that will fit on the bike. Just a gallon to a gallon and a half bigger that is compatable with the fuel gauge and bolts on. I work about 40+ miles from home and often get home on fumes. any help would be appreciated.

Thanks cc

[Griffin]

deerejohn, does this describe your problem?

"The 32mm Mikuni CVs, as they come from the factory, provide borderline unacceptable carburetor response on the 550 engine. It takes five to ten minutes of engine warmup and riding to work their best, which isn't any too good. Unless the engine is revved very high off the line, the bike will gasp and falter, faking out the traffic behind you at the stoplight. Rolling on a handful of throttle at any speed has the opposite effect, i.e. it slows the bike down, leaving it bogged in an immense flat spot. It is actually possible to kill the engine in a slow, tight corner by whacking open the throttle."

This is from the August, 1982 Cycle World test of the 1982 GS550M.

So, you may have your carbs perfectly clean, synced, and adjusted correctly to factory specs, and the bike will still run like ass. There are two possible solutions, one cheap, and one a bit more expensive.

What Cycle World did (and I also did on my GS750E to cure a mid-range stumble) is remove the needles from the slides and flip the spacers around at the top of the needle. As they come from the factory, the thicker spacer is above the needle flange, and the thinner one is below the flange. If they are swapped, needle height is raised, richening the mixture.

Here's what Cycle Word said after they made this adjustment:

"We had similar rideability problems on the GS450 we tested last year and cured them by swapping two washers around on the carb needles, effectively raising them to provide a richer mixture. The GS550 carbs are identical in design, so we tried the same washer trick and it worked. With the needles raised, the choke can be switched off after a short warmup, the stumble is gone off the line and there is no staggering flat spot when the throttle is twisted open at any speed."

Your other choice is to shell out $100 for a Dynojet Stage I kit. I'd try the needle shim swap first. It worked for Cycle World on two bikes (including yours) from this era, and it worked for me as well.