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Okay, so I was having some slip-ons installed when I got my 1000 mile service on my '15 FLSTN Softail Deluxe. I kinda talked myself, or let myself be talked, into an air cleaner and a Power Vision map download...

I love the difference in my bike. My new V&H pipes are nice (a little loud, but I am getting used to it), and the bike's PERFORMANCE is ridiculous now--almost like having a different bike, really. I had heard people say that, but you just don't get it until you experience it.

The only problem is some deceleration popping. I've read that some is probably normal, and some is actually normal even on stock bikes--you just don't hear it very well or at all. I don't know, though, this seems like too much, but I am just too inexperienced to know. Let me try to explain and see what you guys think:

Maybe I used engine braking too much, but with this new setup I cannot gear down under much load at all or I will get popping. If I gear down by the owner's manual (5th at 50, 4th at 40...) then it is usually okay. If I gear down aggressively, though, like before a curve I want to fly out of....pop pop pop pop

I think I could live with that, since I don't need to aggressively gear down very much; but the real thing that is bugging me is that almost any gear if I come off the throttle quickly then I get some popping when I am not even at very high RPM. What I mean is, say I am in 3rd and just tooling along at 30, if I release too quickly....pop pop pop That just doesn't seem right to me. If I ease off, then it is usually okay. (And, of course, if I quickly go to zero throttle and pull the clutch it is fine, too. It only happens when under load, as stated.)

I'm trying to adjust my style to avoid it, but I wondered what you guys think. Everything was installed by the HD dealer, and they told me to expect some popping. I just don't know if there should be this much, whether I should ask for another map, etc...
 

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When you close the throttle quickly your gonna get popping of some kind. If its not loud as in BANG !!! Should just talk to you a bit and grumble also. Contact Power Vision, tell them what you have, may have up dated map. Just because HD Tech performed the work does not mean its right.
Check your muffler clamps and where head pipe bolts to the head. They may have loosened head pipe nuts to get everything lined up and did not tighten them properly. There is a procedure per HD manual for tightening. Get HD Repair Manual money well spent.
 

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I had that same problem with every "tuner" I ever used. Changed maps a bunch of times with same results. I hated it. This time when I bought my new bike I had the dealer just do the simple download. My bike runs great, crisp and clean, with no backfires or pops at all.
 

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Which VH pipes did you get, and which baffle are you using?


It shouldn't be popping.

If an exhaust is too free flowing or too short, it will cause popping.


My Thunderheader used to pop on decel until I added a restrictor plate in it to restrict how much air was allowed to enter the exhaust on the reversion pulse.

View attachment 321722

Do you have a dyno graph with an A/F mixture reading?
 

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I kind of like a little backfire on de-cel. Does anyone know or remember that was the sound people thought they heard when JFK was shot in Dallas. Another way the metric bikes could make that same sound is by quickly shutting the kill switch off during de-cel and then switching it back on. It is raw fuel loading up in a hot exhaust with lots of air to go with it.
 

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I had the same problem

I decreased the parameter "deacceleration enleanment" in the PowerVision software down to 60%. That removed 99% of the decel pop. I might try 55 or 50%, but I'm right now i'm pretty happy.
 

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:thumb
 

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I kind of like a little backfire on de-cel. Does anyone know or remember that was the sound people thought they heard when JFK was shot in Dallas. Another way the metric bikes could make that same sound is by quickly shutting the kill switch off during de-cel and then switching it back on. It is raw fuel loading up in a hot exhaust with lots of air to go with it.
I agree with XL, I have Samson mufflers on an EVO with mild cam and high flow breather. The set up is correct, tuned and dyno'd. If I let off the throttle completely on deceleration then yes I get the pops. If I let off gradually I can control and eliminate. As XL noted it's un-burnt fuel saying hello.
 

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I miss the popping sound. My Yamaha would really let her rip going down the hills when we were up at higher elevations. This Harley is super quiet.


Its running to lean.
Could be too rich as well. As I said, my carbed Yamaharley would do it in the higher elevations.

After it's cooled off, stick your finger in the tail pipe. Should be able to get some soot on it, but not too much.
 

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Before I took delivery of my '13 dealer did stage 1 with HD download. Excessive decel popping and I mean EXCESSIVE. Had dealer do 1,000 mile service and asked them to check about decel. Picked up bike and rode not very far, went back to dealer EXCESSIVE decel still there. Service manager said it won't hurt anything and there is no way to get rid of it. Wrong answer. I put a Thundermax auto tuner on and that fixed it--no decel whatsoever.
 

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I did stage one with pipes, breather and slip on's. popping wasn't bad enough to bother me but it was noticeable. Gave myself cams for my birthday last year then had her dynoe'd, could not be happier.
 

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I have V&H straight shot slip-ons, Screamin Eagle stage 1 intake and the dealer did the remap. There is some popping on a hard decel which I think is normal. The dealer remap brings the bike from really lean condition as a result of the exhaust and intake changes to the normal lean condition from the factory. A minimal amount of popping isn't indicative of a problem, true back firing (more like a shotgun blast then popping) would be.
 

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Discussion Starter #18
Sorry guys, been out of commission for several days--gotta work to pay for this thing!

The solution for me was a V&H FP3 tuner--seems like all the performance of the canned Power Vision that HD installed without the crazy pop. I can force a pleasant little grumble and faint pop if I downshift REALLY aggressively, and that's cool by me.

Took about 10 minutes to program the bike and I couldn't be happier. I'm running the stock map for my setup and really see no reason to change it, but of course I will play around with the autotune just to see what it does ;-)

I read a lot about this "issue" over the last couple weeks. I think when some people are adamant that it is normal / abnormal the difference in their opinions is probably the degree of the pop. Mine was obnoxious, annoying, loud, irregular sounding--pop pop...rattle.pop..rattle...pop pop. I feel confident saying that almost nobody would like what I had or consider it normal. On the other hand, if you read enough about this you will probably conclude that some pop *is* normal so I can't totally agree with the no-pop-at-all crowd either.

It may be too early for a recommendation of the FP3, but if I had it to do over again I would have installed my own A/C and slipons, and with the labor costs I saved I could've just about got the FP3 for free.

EDIT: One more note. FYI, the HD dealer did agree to try new maps until they found one I liked, free of charge, so I have no complaint with them. That just seemed like a lot of hassle going back over there, so I just decided to go FP3 after reading so many good reviews. I would have asked for a refund on the map download, but they didn't charge me the normal $200 license fee, only $80 for the download. I have that download saved in my FP3 in case I ever want to take it to them for dyno or warranty or whatever. I kinda would rather have my original HD map, but whatever...
 

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There is a very simple rule of thumb here. The more you modify an engine for higher performance, the more popping on decel you are going to get. Go to any track. Every motor on everything (bike or car) that is running in the races is going to pop on decel, that's just the way it is. Some guys running 'milder' performance modifications, yes you can tune that out, but in reality is you are detuning the motor and not getting the optimum performance you might otherwise see. My own bike sounds like it's straight off the drag strip, but I love it.

Bottom line is that it's the old different strokes for different folks. Whatever makes each of us happy is the only thing that counts.
 

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Discussion Starter #20
There is a very simple rule of thumb here. The more you modify an engine for higher performance, the more popping on decel you are going to get. Go to any track. Every motor on everything (bike or car) that is running in the races is going to pop on decel, that's just the way it is. Some guys running 'milder' performance modifications, yes you can tune that out, but in reality is you are detuning the motor and not getting the optimum performance you might otherwise see. My own bike sounds like it's straight off the drag strip, but I love it.

Bottom line is that it's the old different strokes for different folks. Whatever makes each of us happy is the only thing that counts.
That's about the conclusion I had come to after the best due diligence research I had available. I put on about 100 more miles today, and I may not have *quite* the performance I had with the power vision, but the difference is negligible, and the ride is *much* more enjoyable and *appropriate* to the bike (and just as important, to me), IMHO.
 
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