Carbon fouling problem

[earlfor]

Yep, works just fine. :-) The point I was trying to make is that if youre a bit rich, you can restrict fuel, or increase air. The result will be the same.

E.

No air box lid effects the intake enough that the vent lines should be removed, just as with pods.

[KEITH KRAUSE]

Yep, works just fine. :-) The point I was trying to make is that if youre a bit rich, you can restrict fuel, or increase air. The result will be the same.

E.

Okie-dokie Earl.
Jethro says his problem is only at idle though. Apparently the other throttle positions burn well. If he DID want to remove his lid, he'd have to re-jet for the other jetting circuits, which he wants to avoid. He just wants stock everything.

[Jethro]

Okie-dokie Earl.
Jethro says his problem is only at idle though. Apparently the other throttle positions burn well. If he DID want to remove his lid, he'd have to re-jet for the other jetting circuits, which he wants to avoid. He just wants stock everything.

That's right, just as god (Ichiro Suzuki) intended it!

My bike idles like a champ, will idle at 1050 RPM all day long. But a little stutter as I leave the stop lights (unless I blip the throttle first).

[KEITH KRAUSE]

So Jethro, did you install the vent lines? Any change to the stutter?
Also, I forget if I asked...does the stutter get worse as the bike warms up? If you let it idle a moment, then blip the throttle (completely warmed up), do the rpm's jump up then DIP down below the normal idle? Both are richness symptoms.

[Carter Turk]

What about the emulsion tubes ovaling out, allowing more fuel past the needle.

I bought a set of 90 GSXR 11 carbs for my 1150 5 years ago with a used probably tinkered with Dynojet kit and used K & N's.

The needles looked really blunt on the end more so than stock.

So, I bought a Factory jet kit with needles that had a taper not a blunt end. I thought I would get more precise metering for fuel/air.

I popped those in to reccommended settings and fouled more than a dozen plugs. I leaned the pilots, lowered the needle, lowered the main, turned the airfuel mixture screws in, leaned the floats, replaced the needle jets, nothing would keep the plugs from fouling. I bought new filters, thinking that might be it. No!

I realize these carbs weren't designed for this bike, but heard other people had success with this set up.

I went back to the Dynojet kit it came with it ran finally. My unscientific explanation is the fattest part of the needle is a different diameter.

I also remembering hearing the GSXR carbs emulsion tubes had a tendency to oval over time causing a rich condition.

Thought this might be something to check. Wouldn't the needle be fully down at or near idle? If there was a wear problem there on the tubes, likely fuel would be getting by?

[Jethro]

So Jethro, did you install the vent lines? Any change to the stutter?
Also, I forget if I asked...does the stutter get worse as the bike warms up? If you let it idle a moment, then blip the throttle (completely warmed up), do the rpm's jump up then DIP down below the normal idle? Both are richness symptoms.

Update- I finally installed the vent lines and LO AND BEHOLD they make a big difference. The bike leaves from a dead stop smooth and flawlessly. Did you expect the vent lines to make that much of a difference, Kieth? I sure didn't. I almost didn't install them as I am currently building the ultimate set of carbs for my bike. Clean as a whistle with polished caps and float bowls. I need to get o-rings from Robert.

Anyway, I rode a whole tank of gas through the bike yesterday and even after sitting at a stoplight for a few minutes, the bike pulls away smooth.

Interstingly, I had my float level tubes hooked up when I put the vent lines on, and the fuel level seems to no longer jump around when I play with the throttle. Before, I would blip the thottle and the fuel would instanly drop a little, then fill a mm too high before leveling off. The vent lines seem to slow down the rate of fuel intake/output, making the bike run smoother. Makes a difference.

[KEITH KRAUSE]

Update- I finally installed the vent lines and LO AND BEHOLD they make a big difference. The bike leaves from a dead stop smooth and flawlessly. Did you expect the vent lines to make that much of a difference, Kieth? I sure didn't. I almost didn't install them as I am currently building the ultimate set of carbs for my bike. Clean as a whistle with polished caps and float bowls. I need to get o-rings from Robert.

Anyway, I rode a whole tank of gas through the bike yesterday and even after sitting at a stoplight for a few minutes, the bike pulls away smooth.

Interstingly, I had my float level tubes hooked up when I put the vent lines on, and the fuel level seems to no longer jump around when I play with the throttle. Before, I would blip the thottle and the fuel would instanly drop a little, then fill a mm too high before leveling off. The vent lines seem to slow down the rate of fuel intake/output, making the bike run smoother. Makes a difference.

Yes, I did expect a noticable difference. Like my post back on the 3rd said, removing the vent lines on a bike with a stock intake will result in a rich condition, which is what you had. Your observations of how this effects the float bowl supply/fuel level makes sense. As I've tried to say many times over the last 3+ years, the floatbowl venting is very sensitive to changes. People think it's such a simple thing that it doesn't matter, but it does. As always...pods= remove vent lines, stock airbox= keep the lines on.
I've never taken off or forgotten to replace the lines on a stock bike before, so I had no "test proof" of the effects. But the bike would have to run at least somewhat rich. HOW RICH and what jetting circuit would be most effected was the question. Your test helps prooves that it is noticable.
I'm glad you mentioned the lines were removed though. After reading your posts for such a long time now I've decided you have pretty good mechanical ability and to be honest, I figured your vent lines were on after you said the bike was "completely back to stock". I wouldn't have thought otherwise to ask.
Anyway, I'm glad your bike is running well and I hope others have learned something here too.

[Jethro]

Go figure, make it look like the picture and it will work! I haven't had a stock airbox on either of my GS's for the past 12 years, so I really wasn't used to needing the lines. I imagined it would make a difference though- and it did. Thanks for all the help bros!