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Decel popping

14K views 65 replies 17 participants last post by  dtmmil 
#1 ·
Hi guys was wondering what others have done to get rid of decel popping. I have Lloyd's timing wheel set at +6 and O2 sensors disconnected. I am considering getting Lloyd's VFC-III. any other suggestions...
And yes I looked in the manual :)
Jim
 
#2 ·
If you have an aftermarket exhaust then you will probably always have some form of decel popping. You can do a search on here because there are tons of threads covering the subject. I would think with the timing wheel set at +6 then you wouldn't have much popping problems but every bike is different. Your other option is to put the stock exhaust back on. Don't sound as cool but little to no popping. I rode the Blue Ridge on Friday up to Roanoke and took I-81 back home, great day for it.
 
#3 ·
Well the funny thing is that when I first put the wheel to +6 it seem to go away for a while. I will check the wheel again. Lloyd's Vic is surprised to help that. I am not sure.
I have stage 1 pipes on. The dealer put them on so I don't have the originals.

We rode to Charlottesville yesterday and took the BRPW back. It was a great ride. Only thing is that I am starting to get neck and upper back pain after riding for about 3 hours. Not sure why. I am going to change my riding position to liitle more forward. See how that works
 
#4 ·
Maybe you can try raising your handlebars a bit. They were a bit low for me, so I raised them. No need to remove the fairing, the two rear handlebar riser bolts are upside down making adjustment from underneath possible.


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#5 ·
Try plugging your O2 sensors back in. This may reduce the decal popping.
 
#6 ·
Your timing may be a little far advanced for a stock (or stage 1) tune.

Back it off a bit and see. It may also be advanced too far for your bike. Mine vibrated like an out of balance washing machine at +4. After asking around some Vic boards, I was directed to back it off a bit. Set to +2 and all was well and seemed to have all the advantages of the timing wheel.

Lots say a Vic is going to snap, crackle, and pop. If mine did, it would be fixed or gone. I have a Doebeck Gen +4 tuner. Said I'd never do that but the spark plugs told a story I didn't care for much. All seems well with the tuner and the tune now. Oh and no popping, coughing, or gagging. Burns me up to have to put a tuner on to make a stock bike work right though.

Congrats, and enjoy the ride. Hope things work out well for you. They should.

cheers
 
#10 ·
what model bike do you have

check your exhaust flange bolts bet there loose. Get them tight and go for ride when you come home put some gloves on and re tighten them.
You might have to do this more then once.
I have read where guys have found no exhaust gasket in head port
 
#11 ·
the vfc4 and pcv with at would be compareable to each other in that you can adjust pretty easily.

and i agree, op try plugging in your O2 sensors.


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#12 ·
no popping

running the dobeck AFR + thats gen IV my 13 hammer runs better than ever, popping matters little to me but noticed how quiet it was going down a steep mountain throttle closed. AFR gauge reading 11.5 at the time, wack the throttle and get a 13 reading, i love that fuel controller! i have a factory stage I tri-pro with holes drilled for a good sound, ness filter + 4 advanced on the Lloydz wheel, i am loving the bike even more than when i bought it!!
 
#13 ·
Well I put my wheel to +2 . Much worse.going back to +6 maybe try 7
 
#14 ·
I had mine at +7 for a while, no issues. However I backed it down to +5.5 "just in case".

I am planning on getting a PCV and dyno tune from Kyle at the end of August or beginning of September, at which point I'll sell my Cobra unit.


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#15 ·
Sweet! Kyle will have you running strong and smooth. thumb up
 
#17 ·
Kyle Crandall of KMC Powersports in Westerly, Rhode Island. He's one of only a handful of Expert Victory Technicians. He's one of Lloyd Greer's Qualified Mechanics and he's a great guy. thumb up
 
#18 · (Edited)
Ok guys, I'm from a slightly Different world with quads and dirtbikes and mainly carbs (but good ones though, FCR's are badass) but typically a decel pop is caused by a lean pilot circuit and richening that circuit will fix the problem. I realize that we're talking efi here but the concept is the same and the engine is going to react the same, it has no idea whether it's fuel injected or carbed.
Now, I'm not super familiar with efi tuning but I believe the Dobeck style controllers have settings for the pilot circuit if that's what they call it. I'd try richening that circuit a bit and also install Lloydz IAV. With that you can also shut down the rush of excessive idle air coming in and leaning the circuit when the throttle blades close.
 
#19 ·
dobeck AFR + adds or removes fuel

i am no tuner by far but my recently installed dobeck AFR + aka Lloydz Gen IV controller cured the decel pop. my understanding is unburned fuel in the hot pipes ignite, the dobeck unit removes fueling on closed throttle, my AFR gauge reads 11.5 going down the mountain throttle closed. i am still not sure its reading an AFR as some settings do, the idle green setting is said to remove fuel from the programming in the unit. bottom line it WORKS, drilled pipes. ness filter + timing wheel at 4 advanced!! unless someone makes a lightweight 304 stainless exhaust for my hammer my upgrades are complete + i am very pleased!!!
 
#21 ·
easily fixed!...stay on the gas:)

people fit performance exhausts cos they want the plus side of deep gutteral roar when accelerating but then complain at the crackle and banging when they back off:rolleyes:

Modified engines have 'character'

otherwise leave it stock standard factory OEM
 
#22 ·
Jpokerwinski , did you plug your O2s back in and try it ? i had a lot of popping with my bike when i unplugged them, worth a shot


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#23 ·
well i think prefer keeping the o2 sensors unplugged becuase i like that it runs a lot cooler and not so lean. i think i will try putting it back up to 6 and live with the popping. i have heard that the stage 1 pipes will do this, so there may not be anything i can do about it. i plan on putting a VFC on it in the near future.
 
#26 ·
JP,

You can run your timing all the way to +8 without issue. just make sure you run hi test gas. Your popping is from a couple of things

1) check the exhaust gaskets if you do not have the aftermarket ones (Lloydz) get them they seal much better than the stock (none) configuration.
2) The Bike is tuned in the lean configuration, pulling the O2 sensors will help some with the popping
3) if Kyle is tuning it go with the PC-V well worth the coin spent.
4) again if Kyle is going to work on it consider either Drop-in cams or the touring cams. Hands down the best mod I have had done to my XCT. Still smiling like a child everytime I twist the throttle.
5) I still get some popping when it is hot out, crap gas is my guess plus 90+ degrees and 90%+ humidity.

I started with my timing wheel at +4 no real impact, moved to 5 and then 6. Kyle tuned it at +6 and on the 80 and 100% throttle setting added another 4 degrees. Bike runs great.
 
#24 ·
try plugging them in just to see if it helps the popping , then unplug again, and i would go pcv or vfc4 instead of vfc3


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#27 ·
im suggesting his bike is to rich on low end and popping, thsts why it does it now after unplugging his O 2s.


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#28 ·
It's definitely lean. Mikuni does a fairly good job describing the condition in their booklet on tuning carburetors. I know it's about carbs and these are fuel injected... Mixture is Mixture.

http://www.mikuni.com/fs-tuning_guide.html
 
#29 ·
It's definitely lean. Mikuni does a fairly good job describing the condition in their booklet on tuning carburetors. I know it's about carbs and these are fuel injected... Mixture is Mixture.



http://www.mikuni.com/fs-tuning_guide.html

i had the same popping with mine, it was stock with thrush mufflers and a lloydz filter, followed the instruction and unhooked my O2s and got popping between shifts, and on decel, hooked the O2s back up and popping went away. all im saying is hook them back up and go for a ride, if it still pops, unplug them again. it will take less time then adjusting the timing wheel.


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#30 ·
Yeah the lead off is when you install an open exhaust on a properly tuned engine expect a little backfire on decal. It's that leaness of the mixture that wont burn in the cylinder but pools in the exhaust and sporadically ignites.
 
#32 ·
leaness wont pool fuel and sporadically ignite, that would be a rich condition!


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#33 · (Edited)
I'm gonna stick with Mikuni on this one I think they have a bit more experience with mixture control, that and the fact that these bikes ship lean. Added to the fact that he has aftermarket high-flow exhaust and he definitely aint running rich. DT you've been talking about different kinds of popping decel popping is caused by leaness while between shifts is usually caused by being rich. Which is why yours went away when you re-connected your 02 sensors and leaned your bike back out. All of these bikes are somewhat different which is why so many recommend a PCV the individual cells are set to what your specific bike needs fuel wise.
 
#34 ·
no im talking decel and between shift popping, for me it was to rich, causing popping , going off experience here.


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#35 ·
You said you had popping on decel then you disconnected your 02 and had popping when shifting and decel. Notice that you disconnected your 02s had no change in decel but you added shifting popping. These are caused by two different things.
 
#36 ·
no i didnt , i had popping on decel and between shifts with the O2s disconnected, i hooked them back up and popping went away.


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