Backfiring and Decel Pop - Is It Bad For Your Motorcycle? | The Shop Manual

[@RevZilla]

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

[@KutWrite]

Which exact knife are you using at the open?

[@rilla513]

​@@KutWrite🎉🎉😂🎉😢🎉😮🎉😢🎉😢😢😮

[@b226tj]

I’ve got a Triumph Speed Twin 900 and occasionally on engine braking, it has started to pop really loudly…(note for later) I was coming into a corner decelerating from Mach Jesus and downshifting when I picked my corner gear and I heard a loud bang from the exhaust. Today I heard a loud pop when decelerating in a higher gear but at a lower speed.

[@patfuryy]

Decel pop is better than k-pop

[@___SSS___]

Emotional damage 😂😂😂

[@lifespanofafry1534]

Amen

[@jamesatwood4433]

False

[@Carlisho]

Both… both is good

[@classychandu5090]

Amen

[@justindavis1546]

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

[@AriH211]

Indeed! I had the throttle body blow off a Husqvarna out in the woods once. It was quite a surprise!

[@sund5]

​@@Seven-yg2srthose were wild. Had a TC610 quite the ride. A lot of power :-)

[@chrisd4813]

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.

[@flatman]

Have you checked the plugs to see if it's running lean? I just got a bandit with full exhaust and she pops like a mf. Gonna pull a plug and see how it's looking in the next few days but it does sound awesome

[@markalan4026]

​@flatman When you install a higher flowing performance exhaust system, you must also re-jet the carburetor(s), or reprogram for EFI fuel systems. You need to richen the air/fuel mixture to compensate for the added flow of the larger pipe, otherwise the engine will run lean. IMO, the explanation given in this video did not put enough focus on how increasing air flow with a performance exhaust, and/or modifying the air intake, will almost certainly disrupt the air/fuel mixture, causing a lean condition. Some of the main symptoms of a lean condition are, hard cold starting, popping on deceleration, higher engine temps, random stalling, poor throttle response/hesitation (especially off idle), and premature engine wear/failure.

[@rwebiscool]

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!

[@CarsandCats]

Shorter exhaust baffles allow oxygen back into the exhaust system due to camshaft overlap which can cause afterfire.

[@seanpatterson5574]

It means your bike needs to be tuned to work with the exhaust you've installed. You likely now have a lean stumble off the bottom too.

[@seanpatterson5574]

@flippy66They normally occur when installing an aftermarket exhaust. They always disappear when the machine is tuned properly. Convincing people it is normal, makes it easier to sell exhausts; as does convincing people it sounds cool.

[@R1ACE]

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 😂

[@TheRealJohnMadden]

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.

[@35764G]

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!

[@JeremiahHartmanPhotography]

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.

[@milodudeful]

Most newer bikes are already running incredibly lean from the factory should still get a tune if you change your exhaust or intake especially is you do both.

[@JeremiahHartmanPhotography]

@@milodudeful yeah they are way too lean. I agree with its mandatory to get a tune if you do air filter and exhaust. But since most of bikes restrictions are from the cat and breadbox resonators..just doing a slipon doesnt really do anything anymore. But getting a tune is always a good idea..these emissions regulations are pointless and in some cases cause more pollution.

[@milodudeful]

@@JeremiahHartmanPhotography Oh ya I see what your were saying now. Ya if you're just doing a slip-on you don't need a tune. Honestly kinda forgot about slip ons cause mine stone was one welded piece so I needed a full exhaust lol.

[@diegopescia9602]

@Oki The Vixen wow and how did you figure out it was the ignition coil? is it a common sympton?

[@NudaMan]

@@diegopescia9602y 03’ R1 sounded like a parallel twin after it got warm one morning and I was so worried I blew the engine or something but nope it was just a loose spark plug on the first cylinder 😂 ended up swapping plugs and ignition coils now the bike fired up no hesitation! It is a little lean with the slip on I got but it runs and rides how it should but it’s for sale currently lol

[@thedragonchatman5815]

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.

[@checkyourself164]

Who is manuel

[@thedragonchatman5815]

@@checkyourself164 manual. That was my spelling error lol

[@rickyrolls6460]

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!

[@AriH211]

Now you know!

[@D-Almighty]

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

[@hexsymbol2229]

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

[@ReddyHHH210]

Can anyone please tell me why does bikes like ducati or any supersport motorcycle produce a loud bang on quick shifting at high rpms ?? I am assuming that it is because the engine is taken away from one or more powerstrokes cuz of quick shifter , so to compensate the drag caused by the no powerstroke cycles , it pumps more fuel and air in the immediate powerstroke ??

[@shogginr557]

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

[@AriH211]

Thanks for the compliment. Can you think of any other topics we should cover? We're always looking for suggestions and ideas.

[@Mr_Doodleydoo]

@@AriH211 Could you do a video on the differences between stock vs aftermarket headers? Once the Cat is removed, would the headers from a full race system even make a difference?

[@ReddyHHH210]

​@@AriH211Can anyone please tell me why does bikes like ducati or any supersport motorcycle produce a loud bang on quick shifting at high rpms ?? I am assuming that it is because the engine is taken away from one or more powerstrokes cuz of quick shifter , so to compensate the drag caused by the no powerstroke cycles , it pumps more fuel and air in the immediate powerstroke ??

[@atem8101]

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

[@Camburger]

Love my cb500f. Received several compliments regarding sound at some red lights

[@MattyT_86]

I have n FZ1, and when I put on a different exhaust system the popping on the overrun was very audible - it did concern me initially, but learning how the PAIR system worked I understood it was nothing to worry about. On a stock exhaust or with the baffle in the current exhaust, the pops are not easily audible, if at all. I can take or leave it, but my father says it sounds very cool!

[@Totone56]

It seems to be a pretty common thing, my SV 650 also has a PAIR system. I wouldn't be surprised if it was linked to the Euro regulations.

[@TheDetroitSlayer]

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

[@Dexter-tx5fp]

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.

[@MRsickcat84]

Hi, any downside with turning off this option?

[@Dexter-tx5fp]

@@MRsickcat84 None whatsoever from a reliability or driveability standpoint. Enjoy the better driveability. Your emissions will go up by a minute amount.

[@MRsickcat84]

@@Dexter-tx5fp great! Thanks man!!

[@Daschickenify]

@@MRsickcat84 You will lose some engine braking (noticeable) and fuel economy (less noticeable) by disabling fuel cut.

[@dusty111]

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)

[@CarsandCats]

You like that? I tuned it out of my Ducati. I like an efficient engine, not a noisemaker.

[@dusty111]

@@CarsandCats efficient is quite difficult to achieve on this engine since there are very few people that know how to tune it and even less that want to do it. The nearest expert i got is located in a different country. As long as power delivery is linear and the engine runs healthy i am happy.

[@Psychx_]

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.

[@desertfresh3740]

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.

[@drjekyll5307]

Yep. Had a guy “help” me get my bike running again and switched the coils.. my god, my bike sounded like a machine gun!10/10 would not recommend.

[@francogestro6037]

I just did this. I’ll switch them back. Should’ve labeled them

[@drjekyll5307]

@@francogestro6037 i need to do that too!! Thanks for the reminder, im working on my bike tomorrow, so its on my to do list 🫡

[@6GearCutloe]

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

[@GeauxRilla]

Guy watched the video and learned nothing 😂

[@billstadelman4420]

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!

[@AriH211]

I'm glad you appreciate the show Bill. Sorry to rob you of an opportunity to rip someone a new one, lol.

[@billv39]

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.

[@Smooveon2s]

Would you say it’s required to get block off plates when installing an aftermarket exhaust?

[@billv39]

Not required but, unless you're an exhibitionist, the popping will be quite annoying. It will stress the packing in your pricey new muffler until it fails prematurely. It will also screw up the air-fuel ratio as indicated by the exhaust, making it impossible to dynotune the bike (it could be temporarily blocked for the tune).

[@WilliamBay]

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

[@thamomentum]

Years of riding and I had no idea. Thanks TSM

[@pauliewalnuts240]

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.

[@ronnievanmierlo755]

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.

[@SquireSCA]

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...

[@Kimsand520]

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.

[@michaelkrenzer3296]

My Buell Ulysses has literally a setting using the Bluetooth tuner to turn on and off decel pop. You can imagine which I choose for daily riding.

[@cfvgd]

You can also install AIS block off plates and almost remove it completely

[@jls.mp4]

riding 4strokes over 2 years now, i still doesn't get bored to decel pops

[@GeauxRilla]

It's been years and I still love the sound 🤷🏽 everything is subjective

[@joebaker5421]

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.

[@AriH211]

There's no reason carburetors can't be tuned for proper AFR. Folks been doin' it for decades. If your mechanic is suggesting that it's "because it's carbureted," then perhaps you should take the bike to someone that knows more about tuning carbs.

[@irish-thinker4429]

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

[@s.crambling3795]

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

[@Kalanioccc]

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.

[@rigididiot]

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.

[@DolfVeenvliet]

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! 😅

[@zxGHOSTr]

Glad to see you recovered well from your accident.❤

[@therealturbofanisme]

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

[@coolgeevee]

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.

[@Ghostsoulless]

Was curious about this. I get some shift pops occasionally after riding around for a long time at low speeds or being stuck at a light for a long time. Glad to hear a single pop isn’t a big deal, and assume it’s a build-up of fuel considering when it happens for me?

[@coolgeevee]

@@Ghostsoullesswhen you say stuck at a light, I assume you mean it pops after you start moving and then shifting, if so that and shift pops after riding for a long time are fine. If it's popping while you're standing at the light, you might wanna get that looked at.

[@Ghostsoulless]

@@coolgeevee Yes, after I start moving and shift into second and third usually. Figure it’s a buildup of fuel from idling for so long

[@coolgeevee]

@@Ghostsoulless it's not a buildup from idling because if it was; you'd hear a constant string of pops. Because once the buildup during idling reaches a point it starts popping in idle itself, that's why I asked if it happens while you're stopped. What's happening with yours is the moment you shift you close the throttle a bit to rev match (maybe even unconsciously) there is one cycle where you sprayed a lot of fuel but because the throttle closed a bit you mixed a bit less air, so net effect you ended up with a rich mixture so the remaining unburnt fuel burned off in the exhaust. You might have also noticed this doesn't happen on short rides but do on long, is just because temperature plays a role too. Overall, from your description, nothing major to worry about.

[@Ghostsoulless]

@@coolgeevee Interesting, I appreciate the explanation. Pretty new to the motorcycle world (come from classic cars), so always appreciate learning something new. Thanks again

[@onenessseeker5683]

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

[@absolemjackdaw6677]

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

[@BennyMalino75]

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.

[@roywalls5595]

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

[@ginoasci]

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.

[@1MrBryn]

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.

[@aluisious]

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."

[@x-man5056]

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.

[@leebanner1309]

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.

[@vincentrobinette1507]

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.

[@GrumpyGoat]

Nice concise explanation of the difference - thanks again.

[@AriH211]

You're welcome!

[@markconlon814]

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!

[@dustywheelz7854]

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

[@seventheleven]

Been meaning to get a carb jetting kit, finally ordered now

[@davidmatthews3093]

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.

[@LTVoyager]

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

[@silentfox8]

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

[@teamtoyota9048]

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.

[@ScottMiller-tu3gg]

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!

[@ARYAAN63]

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

[@StevenMayer6]

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.

[@flyinhawaiian9174]

'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.

[@sirjolly81]

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.

[@233kosta]

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 ;)

[@19Daantje98]

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

[@AriH211]

CLASSIC KZbin comment where someone comments BEFORE watching the video. The bane of my career as a video host. But at least you recognized and acknowledged your error, so thanks for that.

[@19Daantje98]

@@AriH211 Atleast it doesn't happen often tho 😂 I checked your channel. You're the guy from RevZilla, but on your more private account.

[@steventhompson3507]

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.

[@rebeldoc0133]

The MT03 /r3 also pops like crazy when u install a full system , nothing to worry about right? Cuz it was brand new And now im in 6k still banging the same

[@krassas2973]

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 😅)

[@andyandroseadventure]

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

[@kaziashiqueelahi7888]

Bro, you started making video again ?? Glad to see you !

[@caty863]

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

[@d.l.horton2093]

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.

[@CarsandCats]

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!

[@ricatiman]

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.

[@20Unknown]

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.

[@alexandergotz5568]

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

[@jaybosher6144]

My t7 started popping a lot after I put on a high mount slip on. Figured it was OK since I didn't touch the stock cat. It's crazy how much work they put I to stock exhausts to silence them and still run well

[@Lexx1976]

Which one do you have. I mounted on the MIVV Dakar and it's too loud with the db killer it comes with . I bought one with a smaller diameter and it's much better now. Much less decel popping. Almost the same volume like the oem exhaust, but a lower frequency.

[@jaybosher6144]

@Lexx1976 I ordered the short version of the huzar exhaust. I wanted the mivv or the ho corsa but I went cheap and rolled the money into other parts lol. It's a good pipe but it didn't come with a dB killer so yeah its loud. I ride with ear plugs since my helmet is so load so thats more of an issue for me than the pipe.

[@Wintersdark]

​@@jaybosher6144Really? My Huzar (also short) came with *two* baffles. With both installed, it was roughly the same as stock, with them removed it's about the same volume as stock with its baffle removed. Apparently running both baffles on the longer (500mm) can is significantly quieter than stock.

[@jaybosher6144]

@Derrick Whittet damn yeah I didn't have squat in my package. Figured it may have been extra. I'll live but I'd like to have something so im a bit more subtle when I'm riding around the woods

[@robinv2758]

As someone who has 3 KTM 390s with 3 different exhaust setups I can confidently say the less stock exhaust there is left the more pops you'll get. I have one with a stock exhaust which doesn't pop at all, one with just a slip on without db killer which pops occasionally but not too often and not very noticeable, and then I have one with a decat and slip on but with db killer to not be too obnoxious and that one pops like crazy when you let off the gas and it drops below a certain rpm

[@oscarkarinkanta]

if it is newer than 2017 then it is because it is running very lean. The new dukes don’t compensate with more fuel due to emissions. So the more you increase the airflow the leaner it will run.

[@robinv2758]

@@oscarkarinkanta I know the newer ones run very lean, oddly enough my RC390 which is a 2018 models with the slip on only has very few and rare pops while my Duke 390 is a 2016 with a decat and slip on that has a lot of pops, the difference in cat and no cat is very noticeable

[@CaffeineFreak13]

I had a decel pop after installing a TBR system on my last bike and it sounded cool. Then i learned how to do it intentionally for showing my buddies and got it to throw flames lol. I didnt even consider the fact that it could be hurting the bike. Good info here!

[@Rettungssocke]

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! 😎👍

[@NBSV1]

See if there’s a way to block off the secondary air injection system if it has one. That’s usually the biggest cause of the decel popping.

[@Rettungssocke]

@@NBSV1 I pretty much doubt that... i mean its from 2004 and it is carburated.

[@NBSV1]

@@Rettungssocke They had secondary air systems back then. My 2002 Kawasaki is carbureted and it has it. Even with the carbs tuned decent it will suck in fuel when off the throttle, then the air system lets in fresh air which will let it burn in the exhaust. If you plug the ports it reduces the popping quite a bit.

[@Rettungssocke]

@@NBSV1 Oh okay... well anyways im glad its just decel poppin on my cbf... i was about to ask the mechanics to fix this stuff but they would probably rip me off and tell me bs... ^^

[@captaintoyota3171]

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

[@nayemislam2903]

Bro if you have time, please make a video on motorcycle security tips. It will be much appreciated

[@Kiwiriderandcarnut]

I had my Ducati monster tuned and all it did was dump even more fuel to already rich airhead. The decel pops were fun....for a while. Still get the odd airhead trait of airbox vacuum pop (infamous on old boschtronic Porsches)

[@wradford1]

My bike only decel pops when I release the clutch while slowing down. Sounds great too

[@RVAMotorsports]

Decel pop is rad, to a point...

[@o0Bananaphone0o]

Just recently got a KTM 950 SMR with full Akrapovic pipe on it. As soon as I close the throttle, it pops ALL THE TIME. Really annoying. Gotta remove the SAS like I did on my 950 Adventure to fix it. Zach probably appreciates their sound just as much as I do 😍

[@stevenfxgp]

​@@o0Bananaphone0o I love my 990 SMR, popping constantly. Matter of taste, I guess

[@RVAMotorsports]

@@stevenfxgp true

[@passionbaitsza]

Love mine popping sounds beast

[@tbone5448]

Makes the throttle smoother if its tuned for fuel on deccel

[@aaronwinter447]

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.

[@adriengahery9471]

Not so much tinkering on this episode, yet very well informed ! Keep up the brilliant work !

[@Gchethan31]

My single cylinder motorcycle decel pops , it's exhaust is conventional and long. Stock. Now I relaxed. I was worried about tuning even though my dad said it's normal.

[@jonobester5817]

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..

[@Brabobiker.]

I would highly recommend a ECU flash after a new exaust install. Those pop and bang can be fun, but as said it is a sign something isn't right (lean/rich).

[@michiganmoto7687]

Really only applies on a full system. Just swapping to a slip on should require changing fuel mapping.

[@everrybody]

What they don't mention is decel pops are for emission compliance as it is burning unspent fuel before it exits the exhaust. -honda r&d tech (not me)so if you have a Honda with a high flow exhaust from 2010 and up and it isn't popping. Something is broken

[@hainhatphung1371]

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.

[@148Reaper]

Love the loud pops when i blip my throttle on deceleration.

[@b5454]

Can you do a shop manual video on safety wiring a bike for the track?

[@TheGardenSnake]

1:50 bet that's off a CRF300L Rally

[@eatsblades]

Nice vid man. You're right lots of modern bikes are designed for decel pop..

[@aadithyen]

I have a CB350, and it's almost a year old. But almost from factory, engaging into first has always been a mess. Quite tight, loud noises and would jerk the bike forwards a bit, and would sometimes would just return back to neutral. The showroom said it was due to the auto choke pulling up idle revs on first startup, and it was completely normal. But it occurs always, not just during first startup. I've made it a habit to just start the bike in gear with clutch engaged. Is it bad to do that? And what might be the problem causing the noises during first gear engagement.

[@11begood31]

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

[@11begood31]

Thanks for posting this informative video been thinking about the entertaining popping for some time ,I don't get the greatest gas mileage but I don't worry about that not on a ride like that

[@wouterpetersen4715]

My father had a backfire problem once on his bike, the cause was a camshaft sensor that was not working probably.

[@NeverImpossibleTX]

Been backfiring for months now… glad I know

[@matthewsterpka1067]

Should you get a power commander to get your gas ratio working properly?

[@matthewhattia7091]

Question, how does that damage the bike?