Decel Popping

[crimsonultra]

Ok guys here's a stupid question but I'm going to ask it anyway. What is decel popping? Is this something that is obviously noticeable/heard. Like WOW! what was that, or is it subtle that only a trained ear would hear. I was reading a thread where a guy put new slip on's and now he has decel popping. The recommendations were to ensure that he put the muffler way up on the head pipe. The reason I am asking is that I put Monster Ovals on my Ultra, and I occasionlly hear a slight pop when I roll of the throttle, but here's the thing I also heard this slight pop when the bike was 100% stock. So do you know you have Decel Pop when you hear it? Or am I just reading into things? Thanks.

 

[glider]

Stock mufflers will give you some decel pops and the lower restriction aftermarkets enhance the sound so it's even more noticable. Hard to tune it out completely.

 

[crimsonultra]

Glider, and Hobbit thanks for your quick response. If I read your reply's correctly decel pop is something that is just there, and is to be expected weather stock or after market. If so, why are people always asking how to qet rid of it like it will do damage to the engine or something? Does it do damage, and at what point do you do something about it, if you even can.

 

[glider]

It's an ignition of unburnt fuel in the exhaust more common when a custom map is used. The stock ECM programming cuts the fuel on decel , then restores it again when the RPM's get to about 1500 or so and when you alter the tables, you may get more aggressive decel popping. Many try to eliminate it but in doing so throw the fuel mapping out.
You'll actually see a flame inside the muffler if you were following someone when it popped on decel.
No big deal if you have some popping on decel as long as it isn't excessive which would indicate a problem of sorts.

 

[Flashback]

you should know if your decel popping. it's a distinct sound and only happens when you let off the throttle and dont pull the clutch in instead of just a general rumble of the engine slowing the bike you will hear pops and sputters how loud it is depends on your exhaust system as stated above it is amplified by aftermarket exhaust so more noticeable.

 

[jimharvey1]

So that's what you call the blue/yellow flames that used to light up the night out of the 1 3/4" Santee drags on my "fire-breathing" 80" shovelhead / '81 FXE. I just thought I was a little over agressive on my cam selection or had the S&S carb cranked a tad bit too rich. Hmmm...decel popping. Now I know. :bigsmiley12: