love the sound you're talking about but isn't that popping the same sound that causes valve damage from running low octane gas in a high compression, high octane only engine? Or is this a post chamber explosion? And would that not increase heat in the exhaust system? Or is it better than running too lean and overheating? If you couldn't tell, I'm clueless on this stuff.

 

Some folks like decel pop, others don't, and some think it occurs only because of a bad tune.



For a full report on Myths & Facts about HD exhaust, you can see a Report HERE.

Below is an excerpt from the report-


Decel popping does Not damage your engine...it is simply unburnt fuel that is burning in the exhaust tract after exiting the engine.

Decel popping is NOT indicative of a bad tune.



Decel popping occurs when one of two things are present.

1. The bike is so lean the exhaust is superheated and is burning the unburnt fuel that is in the pipes (there is always some unburnt fuel in the pipes no matter how lean). This is very rare.

2. The AFR IN THE pipes is just right to burn the unburnt fuel. This is quite a common occurrence when free flowing pipes are installed (whether or not a free flow A/C is installed). It can also occur if there is an exhaust leak that is introducing extra air into the exhaust tract.

Most engines that are tuned for top performance, that also have free-flowing exhaust, will have decel popping. This is normal.


If you have decel pop and you don't like it, (some of us do like it) then you need to do something to change the AFR in your pipes.

Changing the AFR in your pipes, to get rid of decel pop can be accomplished by two different methods, or a combination of the two.

1. Install some TTI’s. This will reduce the reversion, which will result in a change of the AFR in the pipes, resulting in an elimination or reduction in decel pop.

2. Use the decel enleanment strategies on your tuner to reduce/eliminate the decel pop. Do NOT richen your entire map, this will result in a loss of performance AND decreased MPG.

 

Wow Kevin, I am a customer of yours, but sometimes you make some wild statements...

re·port /rəˈpôrt/
noun

1. an account given of a particular matter, especially in the form of an official document, after thorough investigation or consideration by an appointed person or body.
   
2. a piece of information that is unsupported by firm evidence and that the speaker feels may or may not be true.

For the purpose of your "report" you must be using definition #2..... .

I read that "report"..... I saw plenty of opinion offered to address alleged myths & facts, but nothing suggesting a "thorough investigation or consideration by an appointed person or body" was offering a qualified explanation of them.

Just because someone puts animations to their opinions, and states their opinions as if they are fact, it doesn't make them true. Since I'm no expert, I won't debate it here, but I know several people (who know a whole lot more than me) that would take serious issue with several things stated in that report.

Unless I missed it somewhere in that report, the author is nameless, his/her training and experience are not offered for consideration/validation of his opinions, and there are no references (bibliography) for the author's claims and/or conclusions ... that "report" is really nothing more than a fancy opinion piece....

FWIW...... As a vendor, people will expect a certain amount of "marketing" from you. If you are going to offer up a report as some sort of definitive, factual information on a topic, you should be sure to qualify it, or you will lose credibility for all your "reports" and they will all be viewed as nothing more than a marketing piece.

 

YESSSS that's what I was trying to say earlier that confused everyone due to my lack of ability to know what I mean to say and say what I meant when I meant it and mean it and say it while typing it when I'm meaning it while.......DOH! Did it again. So, I talked to a certified HD master technician who does not work for HD, but does have his own shop. This is his full time job. He just works on HDs and not for HD and supports himself. These things must suck?! He agreed that the M8 can have both pipes and intake and no tune, but he acted like it would be stupid to spend the money on those and not get a tune. He hates fuel packs(probably because they steal work from him, but he says they don't do anywhere near as good as a dyno tune). He said that the M8 was not tuned lean to get mpg, they added valves and an oil cooler to do this. He hates the oil cooler and said that this engine still runs hot. He said if you want to increase performance and mpg you'd be better adding an add-on to the oil cooler if you're not going to dyno tune it. He said that there's nothing wrong with exhaust gas explosion, but you're wasting gas, and that you have to install some sort of I can't remember what he called them if you remove the cats and baffles. Something about laminate flow. He said the exhaust doesn't blow out hot air like a hair dryer, but like a card at a time off the top of the deck, just very fast, and that these devices increase the air flow rate letting hot air out of the exhaust by preventing backflow.