Seriously guys, he's trying to make his bike run UNDER 600 rpm!!! WTF?!?!?

Also, decel pop = lean.

 

Seriously, Wideband O2 sensors should be the Timing light of the 21st Century. They tell you in numerical form what the air to fuel ratio is within your motor after combustion. You think you're rich, but unless you drastically changed your jetting I doubt it. Not to be confused with a narrowband O2 sensor, which just about every fuel injection system on the planet comes with. Those just tell the ECM whether each pass by the sensor is rich or lean relative to stoich, but not by how much.

Ya aught to change your signature line to something like, "Just install an AEM Wideband O2 sensor and stop guessing!" so you don't have to explain every time someone comes on here asking how to tune their carb.

It's like that old proverb about giving someone a fish vs. teaching them how to fish. Installing the AFR unit is like telling them, "Here, put this on and answer your own questions. And learn something about how those little brass jets operate."

 

Air-Fuel-Ratio.

There are gauges you can buy (like this one) where you weld a bung into your front pipe, install a sensor, then run it to the gauge. It gives you continuous, real-time AFR readings.

Since the whole question is whether or not your AFR is correct, it's useful information.

That said, these are single-intake, low-performance, simple motors. Unless you've made extensive modifications to your intake, exhaust, valves or compression, then a "cookbook" tune (ie, using jet recommendations someone has already worked out) will almost always get you as close to optimal AFR as you are going to get with a simple carb setup. Detailed AFR graphs are what pro tuners use to optimize fuel injection maps, but they have far more tuning precision available to them than you do with a carb.

Start with the basics: Pull your carb and see what jets you are currently running. See if the idle adjustment screw plug has been pulled. (I bet is has, FWIW.) Assuming your engine/intake/exhaust are stock (or close), take everything in the carb back to stock. Replace all the rubber bits (gaskets and such) while you're in there. Give your slide diaphragm a good inspect and replace it if it's got any signs of wear. Replace the needle valve, and polish the needle valve seat with a q-tip and polishing compound. Go through the procedure to carefully set your float level. If your carb still has the plastic inlet nipple, may as well replace that with a brass one at this time, too.

No matter what else you do, you're going to have to go through all that anyway.

From there, get it all put back together and see what's what.

If it runs well and fuel mileage is reasonable, you're probably close enough. If you'd like to verify exactly where your AFR is at, you can install the above mentioned gauge, or you can find someone with a dyno and do a quick run. You don't need a full dyno tune (good thing, too, since most of the guys running dynos today don't know how to do much more than program a FI computer). Just a run where you get a graph of AFR vs RPM will tell you what you need to know.

Edit: Mattbastard is right. There's no reason to ever worry about anything under about 1k RPM. Set your idle there, and that's as slow as your motor will ever run. Worrying about tuning/AFR at 600 RPM is a waste of time.

 

Perhaps i misspoke so i will slow down and add more info so you can understand matt... the bike used to idol at about 800-900rpm. replaced 2 head gaskets that were shot and leaking. now the bike will idol around 6-800 RPM but wont come off of that idol without coughing and hacking regardless if i snap the throttle or slowly roll it. i have an excessive amount of soot on the pipe. i have decel pop and it really isnt happy but will run under 2000 rpm when riding. the plugs prior to the gasket job were a nice carmel brown. they are currently black but not wet. my assumption is that while the gaskets were leaking the previous owner just adjusted the carb to compensate for the air leak. i am not familiar with the CV carb as i had S+S on my shovelheads prior to this. so i came to the group of people who know these carbs better than i do in an effort to educate myself to be able to correct the problem. perhaps you should consider that not everyone is an "expert" like you before you spout off "wisdom"

 

thank you for being patient and explaining well.

 

Probably- but i /we/ cant teach everything to everyone at once!
Plus, I would have to reduce the 549 to the SQ route of the hypotenuse of the cantilever.
That gets booorish.
Anyone that is even remotely interested in engines and motorcycles ought to know what AFR stands for. It is not a big word like Stoichiometric.
No therums , no magic, no theory.Just dam blatant plain and clear.
Its that simple folk, you CANT read a PLUG anymore on Egas, yet everyone has the answer about lean and rich .
Keep doing it the caveman way.
Most people even if it was real gas at the pump would have no Fn clue how to read a plug anyway.
Why the fight have a modern tool?

 

Considering others on this thread fell victim of your excessively low idle parameters you don't just have to slow things down for me, but since you did, thank you for clarifying your issue.

There is an idle increase screw on the side of the carb. It doesn't physically push the butterfly valve open further directly, it rotates the round plate that the cables connect to on the side of the carb. Turn that screw in and you can see where it pushes against a tab that slowly rotates the plate which in turn increases the idle.

As a sales pitch, I pulled a Super E off my Evo build if you want it cheap. Lemme know, I never used it, went with a Mikuni before I fired the bike up.

 

just had never heard it referred to that way before.

 

i will think about it. always had good luck with the Super E on my shovels

 

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