I searched on here for this but have found bits and pieces to my question. I have a 2012 48 sportster with the vance and hines short shots, fuel pack and high flow air cleaner. I love the sounds of the pipes but I have a friend with a nightster with similar mods but he had the "jake brake sound" when decelerating and I dont. Just curious what I can do to make mine have it? Or anyone with this set up that has the sound or not. I talked to vance and hines about it and they said it happens or not due to when the injectors inject so certain maps will do it and not. Just trying to figure out how to do it with the fuel pack instead of buying a programer and re-tuning it thtat way.

 

Popping on decel is a result of bad mixture control and it's not something you should seek.

 

+1 It's the result of unburned fuel igniting in the exhaust pipes and is the result of 1) an exhaust gasket leak, or 2) too rich of a setting upon closing the throttle.

A properly tuned bike may have some pop, but it definitely should not sound like a Jake brake.

 

Just making sure we are on the same page, I'm not talking about backfiring if that is what you are talking about as far as "popping". But at the same time it makes since that the noise that I'm talking about would be unburied fuel correct? Their fore not good

 

My dyna with the vance and hines 2-1 propipe sounds like a jake brake when I let off the throttle. It has been properly tuned on a dyno with a TTS tuner.

If the bikes properly tuned, thats what it sounds like. (and we're talking no back firing or decel popping)

 

My friends bike I'm referring to is professionally tunes from a dyno and does the jake brake sound (not backfiring) every time he let's off the throttle from high rpm's. Iv hear this decel sound on many of bikes, just wondering if this is how a tuned/ modified bike sounds. And if it's bad for the bike. If it is a result of bad tuning I'm just confused why I have heard a lot of bikes like this, and they are all usually dyno'd or a bigger aftermarket motor in a chopper

 

Exactly what I thought, you sir know the sound I'm talking about.

So can I not attain this without switching my fuel pack to a better tuner and dynoing it? I was told the fuel pack is a cheaper basic tuner

 

I have the same noise on decell... When I took my FUELPAK off and thru into oncoming traffic and put my cobra unit on That was my exact version of the sound it makes now...

 

Haha, well I just talked to Vance and Hines about the fuel pack and the tech guy said the sound is caused from fuel still being injected for a short period of time after closing the throttle. If it is to much it will run rich and to little it will be lean, and said I can find the sweet spot by adjusting mode 23 on the fuel pack until It does the "jake brake sound".

 

No baffles will give you a Jake Brake sound on deceleration ....
Popping on deceleration can be caused by a mixture problem, usually it is lean
but cold air can get sucked into hot pipes on decel and also cause a pop sound.