Better exhaust sound is just a slip-on muffler away! rvz.la/3zXQJQj

Decel pop is better than k-pop

I put a danmoto exhaust on my bandit, and the decel pops are amazing. Roll down a hill with barely any throttle input and it goes popopopopopop the whole way down. Really makes my inner child smile.

Glad you mentioned the correct definition of "backfire". One real backfire can bring everything to a halt.

I JUST installed an aftermarket exhaust a few days ago and was surprised by the decel pops that began after. This video was timed perfectly as I was wondering if that was a normal thing! Thanks Ari!

Great video.. I think most people get decel pops confused with lean pops and worry unnecessarily. Back in the day with carbs and simple EFI systems when you'd put a new exhaust on it would lean out your mixture causing the bike to run super lean and pop on decel (which was bad back then).... newer bikes are popping because of what Ari was saying...from fresh air being injected into the hot exhaust gas...so it's totally fine now.

Bought my R1 already tuned, after 2 and a half years I've got my AIS (pops & bangs) turned back on. I don't see myself getting tired of them 😂

This video has put my mind at rest after installing a slip on to my bike. I was getting popping sounds and grumbling when rolling off the throttle. Thanks!

Rock solid basics, well done Ari! You have a knack for picking subjects that have needed clarification for decades!

learned something new today , always thought that the they were the same thing, first time hearing the word decel pop in my entire life as well. I just installed an aftermarket pipe in my bike and some of my mates would tell me that my bike was backfiring , but thanks to this video i now know the diff of the two. great video as always!

Refreshing to see someone who knows what a backfire actually is. I love that he briefly mentioned off-throttle fueling as well. From the factory for emissions reasons, when you close the throttle completely you get whats known as decel fuel cut. When transitioning back to on the throttle and starting fueling abruptly again, this causes a harsh jerking transition. Any proper flash tune (not piggy-back trash like power commanders) can disable this. The downside (or upside depending on you) is angry demons releasing from your exhaust on decel, with potential for flames depending on your exhaust setup. The off to on throttle transition is 100 times better with this fuel cut disabled. Side note, cars and trucks do this as well. Its not as noticeable of a transition as on a bike, but it still makes a wonderful difference when disabled.

Decel pop is cool, the first 10 times... After that it just became incredible annoying to listen to when commuting or touring. It happend almost all the time on my Tracer 900 with an arrow exhaust that i got it tuned, way less decel pops and the bike ran much better.

I remember watching Ari Henning at the MC Garage when I got my GSXR 600 6 years ago. I just bought a brand new 2023 Vulcan S and now I'm taking his advice at the Shop Manuel. The advice from both the MC Garage and the Shop Manuel have kept me smooth as a rider. Thank you Ari.

I currently own a Buell XB12 and the decel pops are out of this world, i love it. Rolling downhill i get the constant pops and bangs. Got a real backfire twice which sounds way different (having the intake right under your chin so you can literally hear the engine breath makes it easy to tell the difference). The combination of a 1200cc V2 while accelerating and decel pop while letting go makes riding so much more enjoyable. (Remus exhaust + K&N air intake are a nice combination)

This video is really important for a lot of people, both car and motorcycle enthusiasts who love to do burble tunes just to get the "cool" backfires and flames from the exhaust. Probably one of the worst tunes you can ever do.

The CBR500R in the video is a perfect example of this. Bone stock they pop like crazy including mine because of the PAIR valves. Great video

Thanks for this vid. I've gone from a leaky manifold that was causing backfires to a fresh full black widow system on my carb blackbird. But I have been noticing backfires when I'm rolling down the revs. After this vid I'm convinced it's audible decel pops as they're quiet and in line with the audio clip. Thanks for putting my mind at ease. Keep up the great vids

I installed 2 Coffman shorty exhaust on my 2016 FJR1300 and the decel snap, crackle and pops sounds AMAZING!!!!!!!! People be looking around like WTF and I LOVE IT!!!!!!! #COFFMAN

It's funny, because when I saw the headline, I just KNEW it was an opportunity for me to rip a new one into someone who, yet again, gets things wrong. Alas, I temporarily forgot who I was watching. What I really like most about your videos is that you get into the real detail of definitions, and you VERY APTLY explained the difference between a backfire and an afterfire. It really is a hallmark of your Shop Manual Series of videos, and why I never hesitate to recommend them to friends. I know they'll get the best information. Thank you!

YES! BACK fire! It goes BACK through the intake. It's LARGELY a carb problem, but having your plug-wires or coil packs hooked up wrong can do it, too.

Ive had this argument with a few people. Youve also cleared up another argument Ive had about backfire and afterfire.

My 2002 Bandit had custom ground jets and was tuned by reputable garage. It also had a high lift intake cam and a slip on. Carburetors can’t be tuned like fuel injection and thus I had lean areas and rich areas. My rich area was roughly 6.5-9k rpm. If the exhaust was warmed up and I rolled off the throttle from at or above the rich area of the rpm band, I would get decel pops into decel bangs. There was nothing wrong with my bike or the tuning. Only because it was carbureted.

Decel pop is rad, to a point...

Accidentally installed my 1973 CB500 cam 180° out once. The result was true backfiring.

I love Decel Pop!! Love it. On downhill bends I laugh and cheer like a madman!!!😊 Scramble on!!

Great explanation and video as always! I thoroughly enjoy watching your videos and have been viewing them for years! You have always been a great help! Thanks!

That is my bike. Thing is freaking awesome

Finally, someone who knows what a real backfire is. 😁

Great video as usual! I just wish you would've included shift pops too. Just like decel pops on most cases shift pops are fine too as long as it's just 1 pop the moment you shifted your gear (mostly on upshift when you close throttle to rev match, so a bit of fuel remained unburnt and it popped in the exhaust). And in most bikes this will completely disappear with fueling adjustment.

Thanks for this. I did a lot of research and came across info stating decel pops are caused by being lean. However, your explanation of having a high flowing aftermarket exhuast with no cat makes more sense considering a 2 into 1 has a lot of scavenging and no restriction.

As usual, I'm the 2-stroke guy just watching this to hear about what The Normals are worried about. The most spectacular after-fires I've heard were both from bikes with bad ignition condensers. Super weak-ass spark leads to a TON of unburnt gas AND unused oxygen while trying to climb a hill or something. Eventually some of that weak sauce flame is still present when the exhaust port opens, and KABLAMO. A 2-stroke expansion chamber and stinger really makes this bigger and sharper than it would otherwise be. My cousin's 100cc Suzuki sounded somewhere between a .30-06 and a Civil War cannon. My 400 triple did the same thing in the street a few years ago, and it REALLY got peoples' attention.

Years of riding and I had no idea. Thanks TSM

Also trying to adjust the fuel ratio to eliminate decel pop isn't always what's best for your motor...a happy bike is a popping bike, you just don't hear it as much with the stock.

Thanks to your video I now know what causes backfiring and could instantly fix it on my bike by setting the needle one step richer. Engine runs cooler now aswell.

Thanks. I never knew that the perforated screen on my air cleaner was a flame arrestor. Also, at least on GSXR's, it's fairly common to remove the air injection system when an aftermarket exhaust is installed. PAIR blockoff plates are sold for that. That moves the flames to the back of the muffler and lessens the sound.

Nice concise explanation of the difference - thanks again.

Great video. Nothing sounds better than hearing those backfires, ESPECIALLY under the bridge.

I don't mind a little bit of popping. Stock bikes do it, you just don't hear it much because the CAT and mufflers... well, they muffle the popping. But once I do the exhaust and tune, I jam a marble in the AIR hose and 100% block that system. No need for block off plates, a marble does the trick every time...

Thank you now I know what making popping noise when slow down I changes out my exhaust make it look better!!

Dude. So good. Love that you actually explain/clarify the misnomer of the afterfire "backfire" Great video as always.

Decel pop on my 919 is my favourit thing about it 😊

I was surprised by the decel pop on my Multistrada but the dealer told me it was normal. After a while I figured it was engineered in for "character."

Hi Ari and greetings from Greece!! I love your videos and I learn a lot all of those years from you!!! I would love to watch a video of you, to explain what is the trail and the caster angle and if it is factor to choose one bike from an other. ( I am not very good in English so I hope to make sense 😅)

You forgot one major thing to check...Valve clearance. As the valve seats erode, the valve clearances become tighter, increasing valve overlap. Excessive valve overlap invites carry-over during the transition from the exhaust stroke and the intake stroke, allowing unburned fuel and air into the hot exhaust. By opening up the valve clearances, the carry-over is greatly reduced, reducing popping. Too much valve clearance will create more low end torque, but will reduce high speed torque. It also 'hammers' the valve train at higher RPM. When doing a compression check, tight clearances will show low compression, but if the compression seems 'too good', chances are, the valves are too loose.

I'm literally battling this right now. So happy this came out today ! Thank you so much for the vid !

I would love an episode on electrics... Voltages to be precise. At what voltage is your battery charging or discharging... When are you in trouble? How can you tell how full the battery is? How do you know if your battery is dying or your regulator is failing? So many questions! 😅

The next time someone says to me.."Blooming hell you're bike pops and bangs when you're slowing down!"..I'm gonna show them this video!!.🤣🤣....

Did you choose a CB500 on purpose on or was it simply coincidence? I love the burbles and pops that my CB500X makes on the overrun through its standard pipe.

I love you Ari, you're the reason why I work on my own bike, please don't ever stop making videos!

it means you need to turn the airscrew in or change to bigger jets. After making sure the float Hight is correct in the carb. also blocked carb jets can do it

Then you get the people who get those annoying "burble tunes" which keeps fuel flowing off throttle, you see it more on cars, but I've seen a few bikes with them too. Normal decel pop should only last a second or two

my snowblower pops when the throttle goes from full to low all at once. and it’s extremely loud. i’ve had it for years and runs great. starts every season with no issues. has never blown up.

I have a ducati streetfighter 848 with full open Termignoni slip ons. Was professionally tuned. Pops and bangs (like a shotgun) constantly when off the throttle. Also when using quick shifter will pop on the up shift, especially when not warmed up fully(with a nice blue flame). Great video(as always)Pity not more audio examples.

I can program in developing pop and some flames with my tuner, it’s a fun trick to shoot some blue flames once you get the hang of how to make it happen.

Thank you for this info mate. My XR500R head bolts are stripped x3 and when the bike is cold it runs smooth but when it heats up it back fires. Your video helped me understand that is could be compression loss causing the pop. I'll get my bike sorted next week.

I've had pops and burbles and crackles of some sort since swapping my muffler for one without a cat. I really like the new sound, but once or twice when downshifting, when I blip the throttle it pops and usually it's ok but messes with my rhythm, but once or twice the engine actually stalled out when the pop happened, while I had the clutch pulled in.... makes me worry a little now that I might be damaging my bike

I ride a bmw s1000r with midpipe and SC project shorty can. It pops and bangs like crazy at low RPM blips and then gun shot backfire at 8k rpm. I fn love it. I do worry tho that it needs an ecu tune. But at 15k miles no problems so far. The slightest opening of the throttle on decel makes it crackle.

What about the kill switch backfire on carbureted bikes. Are those bad as well?

I hated the fuel cut off when I was riding. It made the bike unridable. I was so glad when I got it turned out of the bike.

Finally a Video that helped me to understand what's going on with my cbf600. Just installed an aftermarket slip on and ever since worried me if that decel popping is going to destroy my engine or not. After one year its still driving and i guess everything is alright. Thanks for the video! 😎👍

My SC Project pipe is still fully noise compliant, but it's pops off the throttle are absolutely musical compared to stock, without being obnoxious.

lots of times your "decel pop" is caused by hot air from your engine mixing with cold air coming in from the surrounding air which makes a pop, it happens especially on chilly mornings/nights

Glad to see you recovered well from your accident.❤

My bike made a super loud gunshot *BANG* once under heavy downshifting.. Never don’t it again since 🤨

My 200cc made-in-India moto called TVS Apache is known for those pop sounds that are loved by many. However, they are only clearly pronounced when the muffler is hollowed, which I don't want to do on my bike. I wonder why the manufacturer doesn't engineer this into stock muffler as a feature bcs it's clearly loved by clients

I have seen videos where Dyno tuners are able to retune the ECU's and give the customer the choice of Pops and Bangs, or normal, quiet operation while maintaining increased power levels. As a Ducatista with aftermarket pipes and factory race ECU, mine has no pops on decel that are audible, but a friend with a pops tune sometimes shoots flames, and makes such annoying bangs... usually on throttle closed decel from about 7000 down to 2500RPM. Riding behind him can be exciting. We should respect peoples need for peace and quiet, and not have ridiculous tunes to make even more noise.

one should perhaps differentiate with the Backfire: too big or no DB killer (bad for the rear silencer) or too short Header (bad for the exhaust valves). In both cases, fresh air is announced through the Muffler and ignites unburned exhaust residues. but if it just pops out the back, it will damage the insulating wool in the exhaust at most. However, if this mixture explodes up to the exhaust valves, it can hurl them back against the valve springs into the combustion chamber or at least cause a second hot flame front on the valve disk

Been backfiring for months now… glad I know

my monster 1200R was having a lot of decel pop with a SC project slip on. After a tune, cleaned fuel injectors and removal of the secondary air system they are pretty much gone.

I removed my stock slip on and replaced it with a slip on that has no muffling, basically an extended straight pipe. Ever since then my carbureted bike 'backfires' (afterfires) like crazy, sounds like someone clapping really loud. Would that still indicate that "all is not well" with my bike setup?

Fun fact; the Thunderheader exhaust system, specifically designed for v-twins, is made to have thunder like decel pops, which sound like backfires. Hence the name Thunderheader.

My old car had lpg. One backfire exploded the air intake. Had a bad coil. My mt09 has a full two brothers exhaust. It has great de cell pop. I can also get it to shoot flames plus loud bang if I floor it then down shift for a rev blip. So excess fuel is in the system. It isn't tuned for the pipe and smells rich. Happy to have rich then lean. So I leave it. 15 000km and still fine.

Hallelujah for this video. A question we get everyday and I will point people to this video for an explanation. Good job Ari

My Yamaha had an AIS (air injection system). Installing after market slip-on exhausts made the bike pop like crazy on deceleration after tuning and syncing. Removed the AIS system since I didn’t need the extra air with the more breathable exhausts and no more pop occurred. It was more so an emissions thing.

This guy has the best vidz

Good presentation. Anytime you open up your exhaust, you must richen the mixture of carb or EFI, or your bike will run hotter. I took the absurd Cat of my bike and installed the Booster Box. Idles better, off the line better, accelerate better and sounds better. If it pops I can't hear it on the bike. It's only louder when you dial it on. But I did notice a few weeks back, a few threads of fiberglass hanging out the back. Haven't seen any since. Meh.

My 650R (bone stock) burbles VERY nicely whenever I ease off the power. It's not very loud, but it's there, it's noticeable and it sounds good to me ;)

Ole corn pop was a REAL bad dude!! He’s the one you REALLY need to be worrying about. 😂

Now you, someone recognised who can explain motorcycle en engine stuff, explain that backfiring is the loud pops from the exhaust, while backfire is actually when the fuel ignites in the intake of an engine. Might get really confusing for a lot of people.. Edit: When I wrote this and started watching, you literally explained this. My bad xD

Pretty simple to tune out afterfire. I've messed around with it a lot when designing my own fuel maps on my Ducati. Basically, you need to cut fuel when TPS approaches zero at rpm. You can get more aggressive at higher rpm because TPS voltage will be higher just to maintain said rpm so you can cut it sooner. No pops for me. I also get 55mpg!

The decel pop on my 99 Valkyrie that has 6 into 6 pipes that someone else put on who knows when and at one time had glass wrapped baffles that are long gone sounds great on decel as well when getting on it and just cruising along, I am loud and proud, I'm thinking if they don't see me they sure as hell hopefully are gonna hear me, four thousand in two years that's how long I've had the bike ,man oh man it's the interstate model at just turning 90 thousand that beast scoots ,sorry for being long winded but you gotta let it out now and then

How does Ari learn this stuff? Does he watch Ari videos like me?😮

Thank you. For awhile I thought my 88 BMW K75 was backfiring when engine braking in 2nd, but its just a deceleration pop. Love the sound.

There are some Quick shifter kits (plug & Play, and tuning required) that also artificially promote decel pop (NOT backfires damnit!), notably with a small amount of fuel to be sparked up at exhaust's end. Fun and game, though shops already tell me this artificial recreation won't damage the engine, it's just that there is a small intervention from that QS kit to trick your bike's ECU spare a few (but unnoticeable) amount of fuel, nothing more. It's actually used in Racing tournaments (armature ones I assume) to let the bike breaths better through rev range aka. quick shifting FTW, and burning unburnt gas also helps with that, though flushing your pipe - probably at every race's end - is a must. Same for street use, I guess. Huge thanks to Ari for explaining this mechanic quirk that even I can't confidently realize on my own. A coincidence that some aftermarket QS kits also have this decel pop feature that's still being "labelled" as Backfire is like an itch on my nuts.

You're a bit off on this. According to the Internet a backfire is gas igniting outside the cylinder, period. Pre-cylinder is def bad, but post is common as hell. Any carb running even a little rich is gonna have combustion in the exhaust when you suddenly let off the throttle. It's normal to hear that pop, pop pop, pop pop. There's just extra fuel in the hot ass exhaust. If you're shit is igniting on intake, yeah, that's a problem. It's all still backfire though. Never even heard of "de-cel pop" lol

My Triumph Speed triple 1050 has the decal pop as standard i love it.

When I fitted a SP race can on my ZX9R c2, it constantly popped on decel, so I turned the fuel screws out a 1/4 turn, still get a slight popping, but not as bad, but I also removed the klean air system!

There are also quickshifters that cut spark plugs, instead of cutting fuel, to chop power just monetarily enough for gears to shift up, with open throttle, and no clutch use. And then there's 2-step systems that cut power the same way, to launch a vehicle at a predetermined RPM, like for a car, the best RPM to launch without losing traction, and for a bike, best consistent RPM to launch without doing a wheelie. A senor that knows when the clutch is held, engages the lower 2step rev-limiter for launching. And then there's turbocharger Antilag systems. All 3 of these lead to unburnt fuel in the exhaust. Turbo Antilag does this on purpose, delaying the spark plugs, so the cumbustions still happen after the exhaust valves open, so they keep the turbo spinning when off throttle, so, you don't have to completely start building boost all over again, when you get back on the throttle, like when exiting a corner. But that style of Antilag system puts a lot of stress on the exhaust pipes, and turbine of the turbocharger. Best used when you don't care about longevity, like a Rallycar time-attack event.

I ended up with this Chinese Apollo 250 Enduro and have had nothing but problems with the cheap carb/s. The cheap replacement cuts out on acceleration and also has decel pops. I'm looking at a Nibbi carb now but not sure what size. Pretty sure the old carb was running lean..

another great Ari video.

Thank you for talking about the difference between after fire and back fire!

Already knew the answer but watched anyway. Any bikes I've gotten new or near new in stock config have had decel pop with you roll off, especially after a stretch of WOT. The harder you roll off, the more pronounced the decel pop will be, but it's still only a few pop-pop-pop and settles down again.

It can be as simple as a leaky exhaust: My old (old? ANCIENT!) Ducati Paso 750 starts to backfire when one or more of the blindrivets holding the muffler together is missing. Strangely, it does NOT backfire if the connection between header and muffler is leaking, only when the rivets are missing. Never heard it backfire on a dirty or poorly adjusted carb. The Honda CB400T I had before it (end 80's, early 90's) did the same: Backfiring on a leaky exhaust.

2:53 thats dedication to drill a hole through a stock can so the camera can pass through.....

Please more I need them!!

My vintage kerker 4-1megaphone has "afterburn" decell pop like a champ. Sounds amazing prolly looks cool at night if i could see it.but i do get an odd true backfire here n there, think its my waste spark ign ignitor being 40yrs old

Dcel popping is a lean condition on deceleration and can be tuned out via the fuel controller..i personally cant stand it but some people love it

Thoroughly enjoying watching this. I didn't understand what was going on when those two dial test indicators were being used on either side of that shaft sat in v blocks and then the counterweights were being struck it was being struck with a mallet. I don't understand how that brought the readings to zero.

i got a buellxb... the only reason i ride it is for the decel pop... netflix was filming a tween show 13 reasons why in my home town and i was riding my pretty quiet dirt bike... thier security tried to force me off of a public road and then came out and threatened to beat me up... i just went home and got my buell... i filled up and rode my bike around that block until my gas light came back on... it was so cool they called the cops out a couple times... but since i wasnt actually doing anything actually illegal they couldnt actually do anything...

'85/'86 Honda Shadows were notorious for decel pops. I seem to recall Honda stopped making them for a few years before coming back with a completely different style with no decel pop; but according to Wikipedia they kept making them from '87 onwards, albeit with the different style. Weird.