Yep, I left a little decel pop on both my Harleys when I reprogrammed their EFI's.. But KLX decel pops - with a slipon - can be really grating on the nerves..

Setting the butterfly to a higher idle runs the risk, during decel, of allowing enough vacuum to the slide to actuate it - not desirable as you would then get a "fuel dump" from the primary fueling system..
A little at a time is the key here - for those wanting to try the same trick - but only after you've set the screw on your stock #35 pilot jet to 3.5 turns out.

 

Or realize the pop is no big deal and live with it if it isn't irritating. My old MotoGuzzi used to clatter like crazy with the proper valve clearance, but it didn't bother me, I knew it was okay. Now the KLXs both rattled and after my experience with the 650 cam drive I knew that wasn't good and wouldn't continue with the faulty OEMs.

I live with the popping on the 650 because it isn't any big deal (full header with Supertrapp that isn't excessively loud according to my wife and a former neighbor, beside whose window I would start the bike at 6:25 am) so I don't get too shook up. Some of those other aftermarket cans may be obnoxious, I don't know.