Decel pop
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, and does not occur with the stock map and free flowing pipes being the only change.
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.
To get rid of decel popping a lot of people put MORE fuel than is needed into the engine/over-richening the AFR so that more unburnt fuel goes into exhaust, changing the AFR in the exhaust so that is no longer optimum for combustion in the pipes. This is just a waste of gas. And if using decel enleanment found on most tuners it is still really hard to get rid of the popping/burbling when the injectors kick back in at about 1750 rpm.
Another way to get rid of decel popping is to change the AFR in the pipes (mufflers/Slip-ons). This can be done with different baffles, a lolipop or Thunder Torque Inserts. The benefit to the TTI's is that it will let you keep your sound, increase the low and mid range power, and reduce/eliminate the decel pop by reducing/eliminating reversion, thus changing the AFR (in the pipes) to one that is not conducive to combustion.
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For reference, the bike normally idles in the 30-35 kpa range. Letting off the throttle is what puts you under 30kpa and that is the area you add fuel in. No where else!
Last edited by jmeiers; Apr 23, 2013 at 01:42 PM.
For reference, the bike normally idles in the 30-35 kpa range. Letting off the throttle is what puts you under 30kpa and that is the area you add fuel in. No where else!
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I put on a V&H Fuelpak - problem solved!
Quick question - If they said they "remapped" it, why does it have a decel pop?[/QUOTE
Either they really didn't remap it or they did it wrong. It was done under warranty. This is why I want to solve the problem myself. Lost confidentce in dealer
It is very rare for an open pipe to NOT have decel pop when it is tuned CORRECTLY.
Decel pop is NOT a problem for the bike.
Decel pop might be a problem for some riders ears.
The majority of the time when decel pop is tuned out, it is done by dumping MORE fuel into the combustion chamber than is needed, thus sacrificing an optimum performing tune AND wasting gas.
If decel pop is really irritating, then dropping a bit of power by running too rich and using more gas than needed is probably worth it-BUT, that does not mean that it was not tuned correctly.








