Fuel issue? Airbox?

[mostholycerebus]

I'm having a weird issue with my 1985 GS550L and am hoping someone can shed some light. The bike turns over strong, fires up pretty easily, but the idle will not stay constant. It seems to have two modes: either low and pretty strong at 950-1000rpm, or it will surge up to 3000-4000rpm.

The carbs were just cleaned by a middle-aged suzuki mechanic. I also noticed that the rpms drop when the bike is tipped left, like put on its kickstand. Then when upright it runs faster. I noticed this when I was playing with adjusting the idle, it would idle ok at 1k when on the kicstand, but shot up when i put it upright.

I did the coil relay mod, but need to look at it again since it was just but connected, not soldered.

One of the intake boots had a tiny, tiny slit under the clamp. But it was sealed TIGHT, we even tested with starter fluid, so i don't think that's it. regardless I intend to replace that boot and the intake o-rings.

Any other ideas?

[Nessism]

Sounds like carb issues. My guess is that you have an overfilling floatbowl issue based on the fact that the bike runs differently when on the sidestand. Did your mechanic replace all the various o-rings inside the carbs or just hit them with carb spray? And that cracked carb boot sounds bad; using spray to judge leaks is not reliable and often misses the problem.

[mostholycerebus]

My cousin had the rebuild done, this is a donor bike i recently received. AFAIK none of the o-rings were replaced, he didn't want to wait for me to order them.

As far as rebuilding, I would have to buy the tools and figure out how to sync them to do it myself, right? Might become my winter project.

I think I may have seen like a single drop of fuel when I was messing with it last, would that be caused by the bowl o-ring too?

[doggies]

Question

I have a 81' 550. What is the relay mod. you mention and what does it do. my bike is doing some of the same things,running way too rich. Thanks.

[Guest]

i would double check the floats levels first
if that is good, i'd check the float bowl valves (that they are not leaking)

and definitely make sure the intake boots and the orings behind them are ok BEFORE further troubleshooting if you want accurate results

an intake air leak may as well be your main problem

[Steve]

I have a 81' 550. What is the relay mod. you mention and what does it do. my bike is doing some of the same things,running way too rich. Thanks.

The coil relay mod uses a relay to bypass most of the stock wiring to send full battery voltage to the coils for proper firing. If you are running too rich, this will not fix it. To determine whether the coil relay mod might help you, check the voltage at the coils when the bike is running and compare that to the battery voltage. If there is more than one volt difference, you might consider the mod. Some guys have found more than two volts difference, so it made a big difference for them. There is less than half a volt difference on my wife's bike, so I have not done that mod.

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