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P.J., Motorcycle Mechanic
Category: Motorcycle
Satisfied Customers: 751
Experience:  10+ Years as a mechanic and fabricator in an independent motorcycle shop.
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My 2007 Road King Classic has Vance and Hines Ovals fitted

Customer Question

Hi my 2007 Road King Classic has Vance and Hines Ovals fitted but it pops and spits back into the air cleaner when you roll off the throttle at low revs can you advise what I could do to stop this.
Submitted: 2 years ago.
Category: Motorcycle
Expert:  P.J. replied 2 years ago.
First let me say this is common and normal.
The problem is amplified by pipes that are more free flowing than stock as they allow more air to be present inside them and cause the combustion of excess fuel inside the hot exhaust pipe.
If you want to get rid of it because you feel that it is harmful then you need not worry as it will not cause damage.
If you want rid of it because the noise is annoying then you're not alone. Many people can't stand the noise.
The only way to get ride of it is by modification to the fuel map. If you have a stock ECM you are limited to an HD dealer, or an independent shop that has a Centurion computer system, to tune it. It will cost around $500.
You can do it yourself by the use of a self installed, and programmed, EFI tuner. You may already have one installed. The prices range from $350 to $850 for this option.
There is a specific programming section called decel fuel cut that needs modified. It reduces, or removes, the fuel within a certain RPM range and during low or no throttle input to help stop the excess fuel that is allowed to be exhausted and ignited inside the pipes.
I hope this helps. Thanks, P.J.