Tuning out decel popping

[Kevin In TN]

Hey Dave!

2009 XB12R Firebolt
US / Domestic model
Software - BUE2D242

My bike has really started popping pretty vigorously through the exhaust on decel since the weather got hot. I want to work on tuning that back out. It has gotten to where it pops even in between gear changes.

When changing the Decel value, what am I actually changing? In other words, does increasing the value add more fuel on decel, or take it away? I've noticed if I just crack the throttle, it will not pop.

Second, what is a good increment to move it while experimenting? 10 points at a time?

Thanks!

[xb9fog]

Stock Exhaust and Intake?
Anything been changed or is it box stock?
Unless there has been some changes in these areas from stock, it should not pop like that and there may be something else (mechanical/electrical) causing this.

The Decel correction parameter, to the best of my knowledge, is a global adjustment for the decel region, and is a percentage.
(ie 100=100%)
higher percentage adds fuel; lower number removes fuel.

Have you tried a manual reset calibration of the TPS?

[Kevin In TN]

Intake is stock (airbox and filter), exhaust is the stock can with the "loop" pipe in the rear most chamber removed.

It popped a little when it was cold out, doing it more now that it is hot. Enough that the guys I ride with (all grumpy old men, like me, unfortunately) started griping about it.

I did not think to try resetting the TPS. I thought the '08 and up models were supposed to be self zeroing at Key ON? I'll see if I can find out how to do that first.

Other than the popping, she runs like a striped ape. Plugs indicate near perfect combustion, pipes don't even blue anymore from not being so lean. That's why I am hesitant to screw it up, and wanted to ask first.

[Kevin In TN]

Just to follow up on this for anyone else working on Decel tuning on an XB -

Adding fuel (increasing the Decel percentage) definetly will get rid of it, in all but the most ham fisted overrun condition.

With a K+N air filter, open airbox, and home brewed muffler, I ended up with a Decel value of 145 - a big increase.

In the course of getting it where I liked it, I noticed an additional function of the Decel correction - tip in throttle response.

By setting the Decel value lower and leaner - at 80 or so - it positively killed throttle tip in. Tip in is the point where you re-open the throttle from closed. By having it set too low, there was tiny delay, or lag, when you ask for increased fuel delivery. This was extremely annoying, as it upset the chassis when trying to get drive out of any corner that i was decelerating through.

Having it set a little too rich, which is where I ended up to get rid of the popping, causes the engine to be a little bit slower about returning to idle. This is only noticeable when you pull in the clutch, and let it return with no load - on decel and in gear, it is imperceptible. Throttle tip in is right on the schwantz, though, and no more noise.