Causes and Cures for Popping on Deceleration

QuestionThere’s a lot of discussion about popping on deceleration and I have this problem myself. What are the most common causes and cures for this problem on a fuel injected twin cam motorcycle?

AnswerNote from the crew:

Popping on deceleration is due to unburnt fuel being ignited in the exhaust. The reason you do not hear this on a bike with a stock exhaust is due to the baffling of the stock exhaust. It is not only much quieter but also does not allow the fresh air to enter the exhaust due to reversion. This fresh air makes the exhaust hotter (think of letting a fire have more oxygen) which aids in the combustion of the unburnt fuel.

To REDUCE (it may not totally go away) popping on deceleration first make sure that you do not have any intake or exhaust leaks. If all that checks out then you can alter the fuel curve at closed throttle to help this problem. If you are using a PCIII then go into the 0% column of the software and alter the fuel curve from 1750-5500rpm. The value you enter depends on your model and setup. Some Magnetti Marelli bikes responded by having a -60 put in this column while most Delphi bikes respond by inputting a +25. Also make sure that you synch the Throttle Position so that it reads 0 while the bike is idling.

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36 Responses to “Causes and Cures for Popping on Deceleration”
  1. TREVOR
    TREVOR

    I have a 2009 sportster 1200 (XL1200L). Recently upgraded to V&H slash slip-ons. I still have the stock intake in place. No reflash or upgrade to ECM. On decel or downshifting I get a lot of popping from the exhaust.
    My question is if I install the heavy breather intake from screamin eagle and upgrade the fuel map would that improve the performance and get rid of the popping on decel/downshifting?
    Any suggestions would be appreciated. Please advise…

    Reply
    • driveshaft
      driveshaft

      Check neck bearings for grease and loosness..they may need repacked or replaced also check slider bushes for play in lower legs as this can cause same effect when traveling slowly on bumpy roads..its usally the beck bearings..one other thing to check is brake caliber to make sure it isn’t loose on the slides..first thing to do for all these things is to get a good jack like an atv jack that will lift the whole bike off ground..then check each place for play or loosness..to check the lower legs it will be necessary to remove the front wheel so each side can be checked and also that no heavy load from wheel and tire fools you into thinking they are ok..

      Reply
  2. Dave Pike
    Dave Pike

    I own a 2006 Harley-Davidson Deluxe which is beautiful. My local HD staff gave me the excuse that back-firing when deaccelerating is normal for a cruiser and stated that all cruisers do this some. Your opinion, please.

    Reply
  3. Tim
    Tim

    My 07 Ultra Classic has a Power Commander with true duels and O2 sensor bypass harness and have the same exhaust pop. Sometimes in the summer it’s so loud I look back to see if I blew off one of the Rinehart muffers. Bought this bike used in 2010 and don’t have the disk or any harness needed to interface with the Power Commander.

    Reply
  4. Keith
    Keith

    I guess I am just an old rebel because I like the pop and crack of the exhaust when I back off or let engine hold back speed coming down a mountain road.

    Reply
  5. George d
    George d

    I had the same problem. I added a fuel controller to add fuel and it never back fired again. I had 12 heritage 103 that ran so lean and hot i used more fuel to cool it down. It worked great.

    Reply
    • Sandy
      Sandy

      @George d is it just called fuel controller or can it be called something else I’m not finding anything called that where I live. Thanks

      Reply
  6. michael hyatt
    michael hyatt

    I have a 2006 Harley Davidson Street Glide with stock 88″ motor. I have installed Rinehart true duals with 4″ Rinehart slip ons. I installed Vance and Hines led fuel pak.I have replaced exhaust gaskets twice. Tightened muffler clamps. Removed injection module and intake. Replaced all orings along with injectors. I have tried several different maps recommended by Vance and Hines. Nothing ever seems to help the pop I get through left side (rear cylinder) exhaust on decel. The pop begins at 1600 rpms and is rear cylinder only. Any ideas?

    Reply
  7. Dean Borne
    Dean Borne

    i have 2015 harley dyna wide glide just change full exhaust to rinehart churchill 2/2 and change air intake to arlen ness deep cut intake and have been trying to remap with screamin eagle pro street tuner still have lots of decel popping and seem like mid-range power a little sluggish now have tried several maps cant seem to get it right any sugestions Help thanks

    Reply
  8. Dale
    Dale

    I have a 2001 super glide an it pops on deceleration. Any suggestions on what I can do to stop the popping?

    Reply
  9. Josh
    Josh

    i have a 2009 harley vrod muscle with toxic v-lux pipe and im am getting decel pop i have a power comander v in the bike but i have never tuned one before. how do i do this myself and where do i get the software? harley wants to charge me 1200 and a local guy wants 700. there has to be a better way?

    Reply
  10. Vin
    Vin

    Have a 2016 flhxs have stage 1 and stage 2 kits added. Recently added new bars and heated grips and now have popping. Replaced fuel filter, plugs, spark wires, exhaust gaskets, cleaned throttle body, new a/c, and replaced TGS and popping. I’m at witts end?

    Reply
  11. dimitrios pana copoulos
    dimitrios pana copoulos

    IS LOOSE SPARK PLUGS AND WIRES CAN COST BACK FIRING IN MY XHARLEY..

    Reply
  12. Paul
    Paul

    What would cause my Harley Davidson St., Bob to backfire and act like it’s going to stall them Surge

    Reply
  13. Brendan Mummart
    Brendan Mummart

    I have a 2012 Harley dyna with alot of decel pop. I installed a stage 1 air cleaner and the vance and hines big radius exhaust. i went with the harley now illegal super tuner. does anyone have any suggestions for what to change on my current map? I bought the software and cable kit to do it myself. not throwing money down the drain by letting harley do it.
    thanks

    Reply
    • Customer Service
      Customer Service

      Dear Brendan,

      Thank you for your patience. In response to your question-

      Unfortunately, We do not have any background or info on Super tuners. We don’t use them. We don’t like them.
      We can only suggest using a Vance and Hines FP3 or a Power Commander V.
      https://www.fixmyhog.com/video/vance-and-hines-fp3-install-016405/

      We’d love to have you be a part of our community. We are convinced you will enjoy the benefits of becoming a member and having access to the best instructional how to videos and professional tips. We would like to offer you a special promotion for your first-year membership.
      https://go.fixmyhog.com/c16769

      Sincerely,

      Mark
      Fix My Hog

      Reply
  14. David Belisle
    David Belisle

    Hi , I have watched many of your videos. I have a question I have a 2017 CVO stage 3 117 cid zippers rs468 cam. I have a power vision. I had CVO cans with fullsac baffles bike run good. I just changed the muffler to ones with a 2.25 baffle there a lot more open sound deep but the bike now has a big flat spot no power from 3400 to 4000. I can roll on throttle slowly ok but still feel it but if I try to juice it in that range the bike falls flat no power all most like cuts out. I added fuel using the global selecting changing the whole map by 1 percent the other areas seem better but big whole in the middle. I continue to add fuel in the mid till 5 percent with no real improvement once I can get passed the flat spot theirs power do you have any idea’s thank you.

    Reply
    • Customer Service
      Customer Service

      Hi there David!

      We’d love to help!

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    • Customer Service
      Customer Service

      Hello Drew!

      That’s a great question!

      The ‘Ask an Expert’ section is currently for members to our online community. We do have a promotional offer if you are interested. This would include access to expert advice (like this), plus discounts, hours of Premium videos, etc. Please feel free to take a look. You can message us right back with your question if you decide to become a member and you will have a response within 1-2 business days from our experts!

      Please follow the steps below to receive the annual membership at the introductory rate:

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      2. Click on the Premium Membership offer.
      3. The Checkout page will display your Premium Membership purchase.
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      If you have any further questions, please contact Customer Service at 1-855-231-0653 at your earliest convenience, or chat with us on our site.

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      Jessica
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      Reply