Is my bike lean (or rich)??

[Anonymous]

I'm trying to figure out if my bike is running lean or rich. It's a 1980 GS550L and I can often smell a faint smell of gas when I'm running it. I'm including a picture of the exhausts, which I put on within the last thousand miles (at the beginning of the summer). They were shiny silver when put on, but the two inside tubes (#2 and #3) are a golden color now, while #1 and #4 are golden with a slight purpleish. The picture shows #1 on the right and #2 on the left.

What does this mean in terms of rich/lean, and what can I do to fix it? I cleaned/synched the carbs at the beginning of the summer as well. Do the screws on the carb need to be adjusted, and if so, in or out (CV carbs)?

Thanks for the help.

--Tyler

[sv650]

Read the plugs

Have a look at ther posts about "Reading Spark Plugs" to get an idea of how your carbs are set. They look like thay may be lean, but you don't know at what throttle position.

You could also use a "Colourtune" plug to view what is happening in the cylinder while it is running.

http://www.xs11.com/tips/maintenance/maint34.shtml

or

http://www.surenet.net/~verhey/colourtune/Intro.htm

are two sites that detail this process.

SV

[rosco15]

looks lean. Mine started doing that till I richened it up. I confirmed I was a tad lean on a dyno.

[Anonymous]

Will the color fade away in time once I've richened it?

--Tyler

[sv650]

No, but

Will the color fade away in time once I've richened it?

--Tyler

No, but there are products that you can use to remove most of the discolouration.

SV

[KEITH KRAUSE]

1 and 4 are running lean. If you're sure all the jetting (including mixture screws) is the same in all four carbs and the carbs are clean, then I think the carbs synch needs checking again. If you hook up the tool and 1 and 4 levels are lower than 2/3, that's the problem. Lower vacuum compared to the 2/3 carbs will create a lean mixture. If you hook up the tool and all the levels are very close, then I think you need to re-check float levels and re-clean those carbs and check for intake leaks. Any "high idle" problems when the motor's warmed up?
Once you correct the problem, "Blue away" will quickly remove the bluing but not much of the golding.

[Anonymous]

At the beginning of the summer, I had the synched the carbs so that #1 and #4 were slightly above the others, as my books told me. I'll go through them again though.

I do get some high idle problems when the bike's warmed up. Would that be a symptom of an intake leak, and if so, what's the best way of fixing it? However, if it's an intake leak, it would seem weird that both #1 and #4 were lean instead of just one of them, unless I had leaks on both sides.

--Tyler

[KEITH KRAUSE]

OK. If your idle raises more than 300 rpm's from cold to warmed up, then you have intake leak(s). You can't check or re-synch the carbs with a leak. Nothing at all strange about which carbs are lean. Each one has an o-ring in its manifold. This is the most common area to find a leak. Make sure your manifolds are in good condition too. Sometimes the clamps are not tight, but the o-rings are the most common problem.
When replacing the o-rings, apply some hi-temp' bearing grease to help them last and torque to 6 ft/lb. I suggest replacing those Phillips screws with Allens. I would then re-synch the carbs and adjust the mixture screws for the highest rpm and re-set the idle with the idle adjuster knob.

[Anonymous]

I tried the spraying a mist of water method. At first, I couldn't get the rpms to drop at all that way, but finally I got tired of it and just went crazy with spraying. Suddenly the bike just shut off (stalled), so I guess I have an intake leak on the #1, but the leak itself must be on the back side, where it's hard to hit with the water.

When I removed the carbs a little while ago, I don't remember seeing o-rings in the connection between the manifolds and the carbs, but rather just a raised portion of the metal. Are there supposed to be o-rings on a 1980 GS550L with CV carbs? If so, would they be on the engine side of the manifolds? The clamps are definitely tight, most of them maxed out. Perhaps slipping an extra bit of rubber in there to tighten it down more would help.

--Tyler

[KEITH KRAUSE]

I'm pretty sure your manifolds have o-rings. The manifolds are between the carbs and engine. The raised area you're talking about could'nt be made of metal if it was intended for sealing. I'll bet this is really your o-ring sitting in its groove. The way you described your water test, it's hard to tell if your leak is the manifold or the o-ring inside it. If you got water right between the manifold and engine and it drops the rpm's, then that would indicate the o-ring. I know you can't get a shot of water in there and see where it's going easily. Usually, the o-ring is the problem.
If it's been several years since they've been replaced, then they usually start to harden by then. Taking the carbs off disturbs the o-rings and they leak.

[Anonymous]

I looked at some schematics of that area on bikebandit and realize that the o-rings weren't where I thought they were. I had thought they were right where the carbs and manifolds connect, rather than where the manifolds and engine connect. Thus, I hadn't been squirting water quite in the right area.

I doubt that the o-rings have ever been changed, and I know that the carbs have been removed multiple times within the past couple years (once by me, a few times by the owner before me).

The bike is having trouble starting at the moment potentially due to other problems, but I'll look into doing further tests and replacing the o-rings and let you guys know how it turns out. Thanks a ton for the help!

--Tyler