Oh I'm not saying the theory is incorrect Steve just that it seems a bit odd to me. I suppose, if one had a CarbTune or something, you could adjust it till the "blue light" comes on, and that's it. Or simply adjust to highest idle and call it good. But I think that people sometimes assume that mix screws will magically fix issues like decel popping when in fact they can be simply exacerbating the problem by dumping more fuel into the cylinder.
I used to always think decel popping was due to a lean mix. While it most certainly can be an indicator, I tend to think more now that it's more indicative of cold air getting into the exhaust, whether it be via pods or bad exhaust gaskets (of which I think people also tend to overlook, they're pretty much good for one or two "seals" then they've been crushed to the point of not being as effective) or bad gaskets around the junctions on stock systems where the two middle pipes join the outer.
My reasoning for this theory is that certain other manufacturers have used a reed valve set up in the heads of their bikes for many years, even back to the late seventies and early 80s as a way to clean up the exhaust gasses without robbing horsepower from the motor. These are a one way valve that allows cold, clean air to be dumped into the exhaus pipes when the throttle is closed. This is designed to ignite any unburned fuel in the pipes up near the headers where the temps are hot enough to do so. The result of this is a popping sound. On a stock bike wih this set up, the mufflers are usually baffled well enough to cover this up or deaden it to the point of it not being an annoyance.
But remove that pipe, and install an aftermarket exhaust and suddenly there is decel popping that cannot be tuned out with carb adjustments.
I at first thought perhaps my pilot circuit was lean, so I added some mix screw. This in fact made it worse. More fuel unburned to ignite in the pipe.
I did some reading, and found out about this system and how to eliminate it (many modern carbureted bikes use this as well, often referred to as a PAIR valve) On MY bike the two easiest methods are either to remove the hoses from the reed valves and simply plumb them into each other. No air gets in.
Another way is to use aftermarket "block off" plates to eliminate the valves altogether.
Anyway, while popping can be a sign you're lean, it can also be a sign you may be rich, and have an air leak resulting in ignition of this fuel in the pipes themselves.
Those gaskets around the "Y" junctions will let air in, and many times that will cause popping. Exhaust gaskets at the head that are no longer sealing completely may also being sucking air and causing it. You can try to tighten up your header bolts, or replace the gaskets and see if t helps.
Even if your LM1 or whatever you use to check your AFR reads that you're good while on the throttle, I think more telling is what happens when you close the throttle. Does the fuel level or air level spike?
I wonder what can be done, if anything, to cure that? I'd assume if you tried to tune that out, it would probably have a detrimental effect when the throttle is opened. Unless perhaps you could decrease the size of the air corrector jet.
I've also found that the popping can be cured by fine tuning the needle clip rather than adding more turns out onthe mix screws. Listen to where the popping occurs. Is it more in the midrange of the tach on wind down? Maybe the needle can be adjusted a half step with some washers onthe clip to fine tune it.
Just thinking aloud. I'm certainly no carb expert, but I DO like to tinker with them alot. There's nothing quite as satisfying to me as far as working on a bike than having it respond as close to perfect as possible in every circuit. I'm not currently happy with the way my ZRX responds at WOT, but I've come to the conclusion that the design of the needles in the Dynojet kit for this bike are simply not as good as other companies designs. The needles in the last half inch look like hypodermic needles, there's no longer any metering of fuel by the needle at that point. I've tinkered and tinkered with these things.
Eventually I'll try a different kit. But even still, the problem is tiny, simply have to back out of the throttle for a split second when you get up to wide open or it sort of gags a little. Many probably wouldn't even notice it.
But otherwise, that bike carburetes smooth as silk. And that is quite enjoyable to me, especially when you're whipping her like a rented mule in the twisties. You know exactly how she's going to respond under any circumstance. At that installs quite a bit of confidence. Like you and the machine are one, it is simply an extension of your body. Beautiful
