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I bought a used 2016 Roadster (first Harley) a few weeks ago and its been great. Among other things its got the Vance & Hines exhaust, Roland Sands air cleaner, as well as a power commander 5 but it still has pretty significant popping during deceleration. The popping sound itself doesn't bother me whatsoever so I wasn't worried about it at first, but I can't help but think that it may be harmful in the long run. I would assume if the previous owner installed the power commander, its been tuned to some degree or at some point, but is there a way I can verify its been done optimally? I've read on other posts that SOME popping is inevitable with such a setup but I feel its quite frequent. If it had to describe it I would say 3 pops every 2-3 seconds approximately during deceleration. As far as MPG I'm getting right around 40 combined. Unfortunately I cannot get into contact with the previous owner currently.
There is a Report on Exhaust that covers decel pop at this LINK that you may find useful.
Below is a copy and paste from the above link-
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Myth #2 “Decel Pop is bad for my bike”
Or
“Decel Popping is indicative of a bad tune”
Decel popping does Not damage your engine...it is simply unburnt fuel that is burning in the exhaust tract after exiting the engine.
Decel popping is NOT indicative of a bad tune.
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.
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.
Most engines that are tuned for top performance, that also have free-flowing exhaust,
will have decel popping. This is normal.
If you have decel pop and you don't like it, (some of us do like it) then you need to do something to change the AFR in your pipes.
Changing the AFR in your pipes, to get rid of decel pop can be accomplished by two different methods, or a combination of the two.
1. Install some TTI’s. This will reduce the reversion, which will result in a change of the AFR in the pipes, resulting in an elimination or reduction in decel pop.
2. Use the decel enleanment strategies on your tuner to reduce/eliminate the decel pop. Do NOT richen your entire map, this will result in a loss of performance AND decreased MPG.
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That said, your plugs look different. I would first look for an exhaust leak.
I have a PC3 and has this issue. If it bothers you, plug it into a computer and go into the fuel mapping. Try adding like 10-20 percent more fuel at closed throttle from say 1,800 RPMs and up. Make sure you DO NOT add fuel at all RPM ranges as you would then be adding fuel at idle, which is not needed.
Thank you everyone for your replies, and also thank you DK Custom for that informative post. I don't mind the popping, I would go as far as to say I like it, but I was worried that it may be a symptom of a bigger issue. I'll take a look for an exhaust leak and will also plug in the PC to see what I can do, I was hesitant because the PC program looks somewhat confusing and I didn't want to inadvertently screw things up worse. Honestly though if the popping isn't harmful I may not change anything through the PC but I guess it can't hurt to get familiar with it.
The plugs look pretty good I think but I like to see more of an end view and a look see at the ring and the insulation color.
One plug looks a little richer than the other (by what I can see of the ring) but thats probably normal IMO.
40 mpg is a little low IMO unless your combined mileage means plenty of interstate vs some stop and go city traffic. I prefer knowing the mpg at say a constant cruise of about 55 mph then I can get a better idea on how my bike is tuned.
The last two fill ups were almost 2 gallons on the dot and the trip odometer read 77.x and 80.x. By my estimate, both fill up consisted of around 20 miles interstate (~70mph), 40 miles cruising (non stop around 55-60 mph), and 20 miles stop and go city. I'll try to get an more accurate/consistent MPG when I can. I haven't had a chance to do anything with the bike since the last post but these are some more pictures of the old spark plugs. I'll update the thread once I get some more information though.
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Do I need a dyno tune?
