shouldn't pop at all....bad tune

 

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.

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.

Even if you like decel pop like the OP, it is always a good idea to check for leaks.

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

Another way to change the AFR IN THE Pipes is to install Thunder Torque Inserts.


If you don't like decel pop, and don't want to change the AFR in the pipes by changing the baffles or 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...although, with V&H and a few other pipes it is definitely more of a challenge.

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 decel pop. To get rid of it the tune is changed from best performance to best performance possible with no decel pop.

I have never heard of anyone ever tuning a bike for best performance (with total disregard for if there is or is not decel pop)...where they are ONLY tuning for performance.... ending up with a bike that has open pipes with no decel pop.

There are hundreds of threads and thousands of posts from competent tuners on this forum who have strategies for getting rid of decel pop, and many of them are successful in doing just that. But they are adjusting the tune specifically to get rid of the decel pop. Why? Why not just tune it for the best performance? Because if they stopped there, there will be decel pop.

Since so many don't like decel pop, they then go and do further tuning (changing the best performance tune) to get rid of the pop.

 

Do you have any evidence to support that, or are you just regurgitating stuff you've heard?

 

Ok, here's the evidence, my Fat Bob with V&H Staggereds and SE Stage 1 AC had a serious case of Decel Pop even after the dealer did their version of a tune on it. Fire Breathing Industries installed a SEPRT and did a Dyno tune on it and the Decel Popping completely disappeared. I now have Dave Mackie 575L cams,
Bassani RR II no Decel Pop.
Bob

 

You don't have a problem. After you have ridden the bike for a while you will realize that the popping can be controlled by your right hand. I really miss the old days...............As a matter of fact I don't remember having any problems with my old carbed bikes at all.

 

This is not even remotely close to true. The areas of the tables, usually ve and timing, are only adjusted in areas that the bike will only ever see on decel. Such as 0% throttle above 1500 rpm or very low map load timing adjustments (closed throttle) above 1500 rpm. How would adjustments at 0% throttle affect 100% throttle or any other throttle position for that matter? You can tune the bike perfectly for maximum performance and not affect that one bit by tuning out decel pop. I tune the bike on the dyno, while getting out what decel pop I can, then get rid of the rest after riding it. You can only do so much on the dyno, it needs real world riding to hear all the popping. Popping does not mean the tune is bad, that's just an extra step after completing the tune.

 

It's been acknowledged that decel pop can usually be tuned out. The question is whether it's indicative of a bad tune.

Take the 55 or 56 Chevy in your avatar picture:
If it has a manual transmission and a carburetor, you probably know that if you're driving along, turn off the ignition for a few seconds, and turn it back on, you'll get a huge bang in the exhaust. There was nothing wrong with the fuel-air mixture. It was fine, about the same as when you were driving along. It's just that it didn't get ignited in the engine.

 

100% it should NOT pop, it is the sign of a incomplete tune, not NORMAL, should be re tuned, and tables adjusted and should NOT pop

 

Depends on one's definition of an "incomplete tune", I suppose. An engine can have ideal and safe combustible fuel/air ratios all the way across the map, and still have decel popping. It doesn't necessarily indicate any kind of problem, or that action needs to be taken.

 

You can see my set up in my signature picture and I get decel pop all of the time. I've gotten used to it and was told it's my style of pipes.