Decel popping can be caused by a lean condition, or a leak, or both. I have an Evo with V&H short shots, with the loud baffles, and even they don't pop on decel. They did with a smaller pilot jet, but not any more.

A slightly louder rumble on decel is OK, bot not popping.....

 

@gree: @gree:

 

You have to remember a dealer is technically only allowed to tune to epa regulations. So unless you have an add-on fuel controller it's gonna be lean forever and even if you did a dealer still couldn't "technically" richen it up more than stock afr's which is super lean anyway.

 

I had a decel pop after Python slip ons, and an air cleaner upgrade and the HD download. I found I had a small exhaust leak on both clamp locations. Used some copper gasket sealand and now all is good.

 

If decel pop is the combustion of unburned fuel, why would a lean condition pop more than a rich condition???????????????????? Just curious.

Chances are, there is a slight leak between header and muffler, fresh oxygen is getting sucked in during scavenging and it is poppin' off.

 

in short because it cools it off enought not to ignite the unburned fuel.

 

gona take a tuning device if not a exhaust leak.
richen up the 0-2% cells depending on where in the rpm's it pops at.

 

On a related note, will decel popping cause any engine damage over a period of time? My recently acquired '03 RG pops pretty well on decel, so I am curious. FWIW, my wife happens to love the sound. Go figure...

 

On a related note, will decel popping cause any engine damage over a period of time?

No....but the lean condition that causes it will.

 

is it a backfire for sure? Or is it valve slap from no back pressure as you added pipes to a stock top end right? Need head work to get rid of valve slap. If it is a backfire it could be manifold leak ( easy to check with quick start) spray around head and manifold if you get a rev you got a leak. Becareful not to get a false positive (pinpoint your spray to just the gasket area of manifold and head). Exhaust leak can be usually found by listening close to the exhaust and head you should hear a leak if there is one. Timing of course is another culprit but does it fire right up and with electronic ignitions probably not there....

 

Hell ive done a bunch with different maps and i still have some low decel popping and I really dont give a S&*T.. .. some of you guys are so anal ........

 

I have an 06 U/C. I had a problem with popping from time to time on decel. My problem was a rattle that was about to drive me crazy. Found out that the baffle in my Rhinehart mufflers were rattling. I installed longer screws in the end caps that snugged up against the baffle to prevent movement. While I had the baffles out I wrapped some exhaust packing around them. I liked the sound better and thank goodness no more rattle. But, all of this rambling to say that since I did this, I have not noticed any popping on deceleration. Whether this had anything to do with this happening is anybody's guess. But it is something you might want to check on. I suppose with the extra packing, it made the muffler restriction more like stock. For information purposes I do have Rhinehart true duals.
Leon

 

Adding fuel at zero throttle position works for a lot of people.

But as others have said, make darn sure you have all the exhaust leaks gone first.

 

decel pop is caused by the combination of fresh air being mixed with unburned fuel being ignited by the heat fom you exhaust no engine damage will ever result the cause is generally an air leak into the exhaust or running to rich, not from runnng to lean because ther would be no unburned fuel in that case to ignite

 

Actually, this is not quite true.
A lean low speed condition causes popping.
The lean mixture is too lean to ignite in the combustion chamber during the piston cycle time.
It makes it's way into the exhaust pipe, and lights off when things slow down inside.
Leaning will just make it worse.
Low speed richening will reduce it alot but, with some pipes and cam designs, it will never completely go away.

 

I have a 2012 Super Glide Custom, stock pipes and I get a lot of decel popping and if I ride without a helment I hear a lot of rattle from the front of the engine. It only has 1600 miles, taking it to the dealer but because I am a new owner (my first bike) I am not sure what I am hearing just doesnt sound right. And because I am new to Harleys I have to trust what the dealer tells me and that is not comforting. Taking it to the shop today for them to listen to and see what they say.