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exhaust popping....

Colt.45

Colt.45

Member
Hey guys
Sorry to always be asking questions but new to H.D. so I'm sorta lost [most of the time]
A month ago I installed Night Rider's XiEDs on my stock 08 Rocker. Seemed like it ran a bit better then the next week I replaced the stock mufflers with Vance & Hines Twin Slash slip ons. At the same time I installed an Arlen Ness Stage One air filter system. Wow........the bike really ran good and of course sounds like a Harley now. I had a tiny bit of decal pop but not much. Now a month later I notice lots more popping and even what sounds like a bit of backfire on decal. I replaced the exhaust clamps with new H.D. when I changed mufflers. I did not loosen the header pipes at jugs....I did disconnect the neg. batt cable when I installed the XiEDs and then reconnected it of course. Since then I have disconnected the XiEDs and reconnected them [they were fine but wanted to be sure]. So, I'm out of ideas.....Anyone got an idea I've missed?
Thanks.......Colt.45
 
With the excessive amount of leanness with both added mods of air filter and exhaust you will want to consider a fueler of some sort.
 
dbmg
Yeah I have been thinking the same thing but am trying to figure out why it has gotten worse than when I first did the Stage one stuff a month ago?
Thanks........Colt.45
 
More might be necessary, it may be getting worse because of an exhaust leak. Re-check your slip on clamps for location on the slip ons and tightness. Check the exhaust flange nuts and make sure they are torqued to spec. If it is running really lean, the heat has certainly risen. That can cause things to expand and contract more that it has before. I think rechecking all the exhaust connections for tightness and torque would be a good idea.
 
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Checking the exhaust flanges for tightness is routine on my bike, usually on the back cylinder I find it loosens up over about a month. I re-torque to 10-20 inch/lb. on top and bottom and final torque is 100 to 120.
 
Actually, the decal popping is uncombusted fuel entering a hot exhaust system and "burning off". The XiEDs only work in closed loop, in other words at idle and cruise. The OEM ECM goes into open loop on decel; the XiEDs are out of the picture. The HD ECM does not shut off fuel on decel so there is some uncombusted fuel that hits the hot baffles in the muffler and burns off causing the popping.

Agreed you should check the muffler to header joint as well as the exhaust flange nut but even if tight, you will still get the decel pop. You need to get rid of the XiEDs and replace them with a better fuel management system that will allow "flashing" of the ECM to control fuel on decel. The TTS Mastertune, DJ Power Vision or the HD SEPST/SEST have that capability. The PCIII USB will also work with the elimination of the O2 sensors but that is a "piggy back" tuner that "tricks" the ECM in a similar fashion to the XiEDs. Either way, a dyno tune will be required to get it right. I have a preference for the flash tuners but check with your local tuner and see what he prefers.

I am not sure why the decel popping has gotten worse but it could be related to the fuel you are using, the additional heat in the exhaust system now that you have upgraded to Stage I and leaned out the AFR in open loop condition even more; just not sure. However, I can say, with certainty, that a more sophisticated fuel management system and a dyno tune will solve the problem. The bike will run more efficiently, cooler and stronger.:D JMHO.
 
Do Harley's have exhaust gaskets? Had the same problem with a Honda once, and replaced the gaskets and no more pop.
 
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