I have a 2015 Breakout, open air cleaner and a thunder header. My decel pop was really bad. No exhaust leaks. Played with the decelleration enleanment tables, not much changes. I finally went into the afr tables at the 20 kpa and dropped it to 13.8, from 1700 to 3000 rpm. Then went to the VE tables at the first column and basically changed the same rpm area to 100 percent or more. The popping is now gone.

Is it normal to have to do this? I had it dyno tuned and that mad a big change as far as the bike runs, but they didn't do anything for the popping.

 

You were able to fix it yourself, which is great, but you should have taken it back to the dyno operator and had them get it right on their dime. Which they should have done the first time. Just sounds like they didn't care too much (or didn't know how) to get it perfect.

 

This place was recommended to me , however as I looked around I saw nothing but crouch rockets and bmw motorcycle. I got the feeling the didn't really know what they were doing. I will have to find a good tuner in central Oregon, or take it to the valley. But I am not going back to that place

 

Decel pop is not so much a matter of a good tune vs. a bad tune, but more a matter of exhaust configuration. Decel pop is Not indicative of a bad performance tune, only that the tuner did not know that you wanted it tuned out for your ears pleasure...or that they did not know how to tune the decel pop out.

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 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, even on the 2015's which are lean from the factory.

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.

Also, check for intake leaks at the intake manifold/heads.

Another way to change the AFR IN THE Pipes is to install Thunder Torque Inserts. Not only will these reduce/eliminate decel pop, they will give a good boost in torque in the low and mid range. See details & dyno charts HERE.


If you don't want to change the AFR in the pipes by adding Thunder Torque Inserts....

It is absolutely possible for a tuner and someone who knows how to use it to tune the decel pop out.

HOWEVER, the methods used to tune the decel pop out of very open pipes are almost always at the sacrifice of performance and/or MPG.

An open pipe with the best performance tune is almost always going to have some decel pop.

To get it tuned out, without just dumping gas in it, you will need to find a tuner that understands how to do it...it is possible.

 

I know what decel pop is. That was never my question. My question was, is it common to see that high of number on the VE tables at 0 percent throttle, and that rich at the 20 kpa in the AFR table? I know it will depends a lot on what exhaust is used. Maybe a better question would be , did I go about fixing it correctly?

 

Apologies, I thought both you and Nevil were flirting with the idea that it was tuned incorrectly.

I do not consider decel pop something that needs to be fixed (from a performance tune standpoint). Any tuning to be done to get rid of decel pop is outside the realm of tuning for performance. It is simply tuning for sound preference. Sometimes it is done where performance is not compromised, most of the time it is done at the expense of performance.

It sounds like you did what most tuners do, you dumped more fuel in, richening the AFR in the exhaust to the point that it will not burn.