Honda Shadow Backfire/Afterfire on Deceleration? - DIAGNOSIS

Does your bike need a little rejetting? Get a TJ Brutal Customs tuning kit for your bike HERE! - shoptjbc.com/search?q=tuning
First of all let's point out the facts :
- BACKFIRE is a sneeze, or cough, popping or little bit of flame coming out of the carb or intake.
- AFTERFIRE is popping out of the exhaust.
So we're going to tackle "afterfire" first:
If your bike is afterfiring, your pilot circuit is too lean. Start by adjusting your air fuel mixture screw(s). If that doesn't fix the problem, the answer is in this VIDEO!
This issue could also be indicative of an exhaust leak, a valve adjustment being out or potentially a vacuum leak (rare).
If your carb is coughing, that's also an indication of a lean condition. TJ explains and gives more details IN THIS VIDEO - so WATCH NOW!!!
---
Like what you see here? SUBSCRIBE to our channel, then make sure you’re following us everywhere else!
Get all the latest updates on new product releases via our Facebook page: / tjbrutalcustoms
Then follow us on Instagram, for all the off-color shit and exclusive content you LOVE: / tjbrutalcustoms
On the hunt for LEGIT BADASS CUSTOM HONDA SHADOW PARTS?! We’ve got ‘em! Check out our shop: shoptjbc.com/. (While you’re there, SUBSCRIBE to our email list at the bottom of the page.)

[@stevefavela9179]

I actually like the backfire pops specifically downshifting before a bridge and letting it pop and then gunning it 👌

[@mrkapusta9935]

I love that this keeps popping up (no pun intended). To anyone who sees this LISTEN TO TJ DAMMIT! I had this issue after removing that gheeeey Honda intake (velocity stacks now)and putting the gorgeous backdraft exhaust on my bike. I was told 10000000000 different things from, “it’s what you get with no baffles”, “you’re chasing gremlins dude!” Etc, etc. In a last ditch effort I listened and READ what TJ said to do... my 750 ace was all set for a trip to my mechanic. I purchased the largest set of jets off of TJ’s site. Double shimmed my float needles. Wallah! Bike runs incredible not ONE BACKFIRE on decel or hard downshifts etc. I was so shocked that I expected to see a unicorn cross the road on my test drive back home. My wife saw the huge smile on my face and immediately thought I cheated on her. THATS HOW GOOD IT FELT fixing that annoying problemo. Ride on my friends....

[@TimothyIpmanchilds]

What these parts , where the webite. I need this ASAP

[@jeffwest6691]

TJ - Thanks for the videos. They are always informative and entertaining. I too, thought my VT600 was running lean because of the decel afterfires. When I rebuilt my carbs I discovered the air cut off valves were both missing!. When I replaced them, no more afterfire.

[@itsreallytom4310]

Finally someone who properly defined afterfire and backfire

[@johnnyabbott5503]

P

[@plumblevelsquarebear8147]

Best description of a backfire/after fire I can find on the interwebs.

[@TJBRUTALCUSTOMS]

Thank you so much mr squarebear!!! !! i do my very best! i appreciate the comment!

[@FirstLightAdv]

Thanks for explaining it in straightforward manner!! Very helpful!!

[@javiersalido8073]

Easy and clear, thanks 👌🏻

[@fastcar1957]

I adjusted my 1100 just as he said and no more popping. Works!

[@wynteralexshoppe9089]

hello i have 1100vstar poping now when i come off the clutch. was that going on with you thanks

[@fastcar1957]

@@wynteralexshoppe9089 no just when letting off the gas at speed

[@boomerguy9935]

My 1988 Shadow VT600C VLX did this when I first bought it with 8400 miles on it when I went downhill from my house with no throttle in second gear. It was really as much a "backfire" as it was just a random "popping" sound which I thought was cool. However, to be on the safe side I synchronized the two carbs because I NEVER needed the choke to start it, no matter how cold the engine was. I gave it a full tune up with new air filter, spark plugs, fluids, etc. The spark plugs were clean so I figured the air/fuel mixture was OK -- not that I could adjust them anyway because they are sealed. After I sync'd the carbs, I noticed four differences: I needed the choke to start it The "popping" sound was gone The idle speed needed to be reduced (I still keep it at high idle as recommended by the service manual.) More power (This is subjective: my butt-meter says I have more torque and I definitely have more power going uphill and a higher top speed which I reach quicker.) Problem solved with just a simple tune up and synchronization which required a manometer and turning one screw. I love it! One extra note: Since synchronizing the VT600 requires removing the fuel tank, I discovered my petcock was bad. It didn't leak when riding but it would not close completely when I removed the tank and dribbled all over the engine when I pulled the fuel line off the discharge tube. This was an easy fix with an aftermarket petcock. So I extra fixed a safety hazard. I love this motorcycle!!!!!!

[@viktord.8018]

Stephen Burgess I just got a 1988 Shadow VT800C 3 weeks ago, and i noticed it does the same thing on deceleration, and sometimes randomly it will kinda struggle when going up a hill under load. Very rarely though, I’m wondering if I may have the same issue. I’m thinking maybe a carb sync will help, where did you get your manometer? Just looking for suggestions, thanks.

[@casparzimmermann8633]

Most often decel poping starts when the stock muffler is replaced with an aftermarket piece. The SAS (Secondary Air System) is designed to let air into the exhaust the help the Cat burn unignited fuels properly coming from the enginge. Aftermarket mufflers increase the airflow through the pipes, therefore nothing is timed to stock anymore. Loosing the SAS should solve the problem. Make sure to fit a dongel to not get any errors on your board computer.

[@MarkoftheMouse]

Perfect video. I didn’t realise there were two types. My bike does both. Sometimes when it afterfires I can feel the force trying to blow the air filter cover off. It never used to do it until I got my carbs ultrasonic cleaned. Only backfires through one exhaust/cylinder though

[@YNTGUNS]

I have this backfire, that happens sometimes in downshifts. Not all the time tho. on my injected 07 zx10r. Valve adjustment was done already and there all in spec

[@Tacbi0325]

Hey bro my motorcycle backfired only when I turn off .. just like switch off and 4 seconds pum 💥!!! Only one time after off ... what u think ???

[@pappydanny58]

Changed my pilot jets today. Got rid of the back fire but front cylinder is making a putting noise through the exhaust. Seems to run ok

[@Young937phoenix]

Thanks for this advice I put a new carb on my 250x honda sportrax and it's fine in first gear but when I switch to second when I let off gas it after fires. It very well could be a valve adjustment issue. It prolly needs done so I'll do that after I adjust the fuel air mix screw

[@IS-vy2yh]

I have upped my pilot jets and shimmed needles. Runs good BUT I very infrequently get a loud pop on decel, is it normal?

[@seanriddell8209]

Hi quick question Got a honda shadow 600, when mid way through the revs it started to burble and no accelerating. It's only happy low to mid range in the revs Is this too much air probs or fuel probs. Many thanks Sean

[@dennisball1091]

Thank you

[@pccidaos]

Hey, any idea to cover the frame neck with metal instead of plastic?

[@briansaunders4308]

so my bike is running a little ruff on acceleration and after I shut it down after riding it pops, its not loud just a quiet little pop, would this be an adjustment.

[@bryanmiller5074]

I used the jet calculator and it calls for smaller jets that are in there now. Mixture screw is 3. Still popping like hell

[@Spaceinvaderzim]

My shadow 2001 750 ace pops on acceleration or at idle ,i cleaned out the carb and adjusted the the fuel mixture screw. Show i buy bigger jets ?

[@marianojeffrey9177]

I would like to know what is the reason when my carb is making a hisking sound? Please help 🙏

[@TorbenVestergaards]

Hi TJ!! Greetings from Denmark, overseas! I just bought one Blaked out mean VT 600 Bobber Split Lane, with a lot of TJ’s candy on it! Paenut tank, v.stacks with Long Air fuel min screws etc etc. I just love it. I seems to have a litlle backfire from the pipes though, when i let off the trottle to fast, ore going down hill a bit. The iddle seems ok, but it stopped for a few times though. Even when riding at low speed it stopped between a gear shift yesterday. I may run a little to slow in iddle, i recon. My Q is: Do i just turn both fuel screws both sides the same way? And wich way? Right side shows number 2 upwards- left side (need unscrew a little cover)seems to have the nr. 1 pointed backwards! Besite that its running like ”a bat out off Hell” I only got it a week now and i F… love it. And people Ask about the sticker with the white ”cross” on the site..🤣Tj Cus!’ Thx Torben

[@StoneBridgePKPossekilla]

You the man thx

[@TJBRUTALCUSTOMS]

🍻🍻

[@TimothyIpmanchilds]

Just bought a Honda Shadow 750 2002 it pulls strong through all gears but spits and backfires when I hold the throttle at one speed what is the website to order the kit I need that website ASAP better yet a part number

[@marc-andretheriault8908]

Do you have a video where i could learn how to ajust the air fuel mixture on VT750C ??

[@jacobrice1409]

Thanks 🙏 Simple and too the point. My “after fire” Is so loud it scares the hell out of me 😬😅

[@TJBRUTALCUSTOMS]

when im tuning its a real butt pucker move from the bike. rude! 😂

[@jacobrice1409]

After this video I took the exhaust off the manifold and the gasket had broken, causing the backfire. I’ve filled it with gasket paste (high temp) and the after fire is gone 🙏🙏🙏 Waiting on the new gasket now ❤️

[@mathewhampton2943]

Im trying to figure out what's going on with my 05 vtx 1300 it's running off 3 heads the one will fire if I ground out the coil but not on the plug I just changed the plug so I'm not thinking it's the plug and I changed the coil so it's not that either

[@dnosbush]

Can you direct me to the mixture screws on my 1987 Honda shadow VT1100C?

[@leedavis5903]

I have a 1998 honda shadow ace 1100 it backfires when Rev up and when slowing down or ilding

[@aliqadri4672]

How lean air fuel mixture cause after fire..???

[@robertomoreno5526]

My go kart 6.5hp motor wont start it only after fires. From the muffler. What can I do ?

[@scottjones5013]

Soh I'll give it a try

[@edwardarroyo8346]

What if you’re on a straight piped drag pipes?

[@johnragosa4193]

I'm getting after fire and I noticed that my front cylinder is cold any help is welcome 2001 vt600

[@glowiever]

what if it happens after you close the throttle? motorcycle is not moving, gear in neutral

[@xxwafflecone]

So I just bought a 2021 z125 pro with yoshi pipe on it, it has tunes and everything and it decel pops 2 out of 3 times when I let of the gas going anywhere between 35-60 mph I don’t mind it and actually think it sounds cool but I don’t want it to cause any potential engine damage so my question being if I were to just leave it be would it fuck up my Engine in any way ?

[@MarkoftheMouse]

Thanks for the video! Seems I have afterfire no back fire then. Could this be caused by a leaky head gasket therefore more air is getting into the engine? I say that because I have changed the pilot jets and mixture and it did not cure the issue. I tried another carb and that didn’t fix it either. It’s only the front cylinder as well and it has a rough idle. I sprayed carb cleaner around the head gasket and at a certain point the revs picked up so that’s why I think it’s a head gasket job.

[@johnhales716]

Same thing is going on with my VLX600.

[@bloodlust1000]

Tldr: If it rumbles or pops when coming off the throttle, its an afterburn which is fine (although you use more petrol but it sounds fub). If it goes bang and your valves shoot out of your engine or your air filter catches fire, its backfired (very bad)

[@TJBRUTALCUSTOMS]

HAHAHAHAH!!! VERY BAD! tHAT WAS HILARIOUS MAN! THank you for commenting! and thanks for the educational laugh!

[@MrNinja-ks8tg]

It will be cool to show how to adjust the screws perfect. My bike pops as crazy when i slow down…. Cops pulling me ove all the time …. I hate it 😢

[@TJBRUTALCUSTOMS]

That's a lean deceleration pop. Back out the mix screw, if that doesn't help. Go up one size on the pilot jet

[@robcarruth4187]

I have a 86 Magna VF700C. Completely rebuilt the carbs. #1 base carb will not idle down even when mixture screw is completely closed. I rechecked the float height, all good. Can anyone help with this problem

[@connortierney9450]

So I after-fire at idle just shooting big blue flames, previous owner installed the screws with the 1,2,3,4 but adjusting it either way does nothing, what do I do at this point?

[@connortierney9450]

@@TJBRUTALCUSTOMS like rust from the tank?

[@bigboi9611]

The previous owner of my bike refitted a supposedly stock exhaust. Before that it pretty much had a straight pipe on it. It is now afterfiring on the front cylinder. Might it be because it was tuned for the straight pipe?And now it's to rich for the stock flow?

[@bigboi9611]

@Nick Gur was a lose bolt on the front pipe

[@danielitoloshuertas4441]

My bike loss of power and is back firing when I decelerat any one that can help?

[@ricklancaster4714]

I've got a ? For anyone...a2002 Honda vtx 1800, sputtering when idle and holding partial throttle. But great when you call on it. Now..efi. I've checked plugs,wires,carbs and intake look perfect, fpr, ...any ideas guys??? Backfires out front carb. HELP

[@Amazingsoup49]

What about when your bike makes a loud bubble noise out of the exhaust when you shut it off

[@TJBRUTALCUSTOMS]

I'm sorry man but I can't diagnose sounds, but that could be a rich condition, just unburnt gas burning off.

[@tsjackson75]

TJBRUTALCUSTOMS I've got an 83 VT750C that is EXTREMELY hard starting (afterfires when cranking). Once started (If it starts) it runs perfectly, idle, midrange, and wide open. Shut it off, good luck getting it started again. Carbs are clean, compression is good, plugs firing...any insight would be GREATLY appreciated!

[@drdoofenshootz7]

Maybe check your float needles? It might be leaking and flooding the bowls.

[@puzyrewicz]

I have the same problem. I bought a bike from a neighbor that was sitting for 3 years. It will start after 10 seconds of cranking. Looks like to me that it is getting too much fuel. With choke open starts to backfire and after-fire.

[@nicfleck3213]

I need help, I have an 84 honda shadow vt700c it idles great but once it gets to 3000 rpm it's like it tracks out it bounces at 3k then backfires, I thought it was a clogged pilot, got them out cleaned them up and still the same problem? Idk what else it could be, maybe the floats out of whack? I'm not sure the specs to adjust it to on my bike any help would be appreciated

[@DeeJayTmipls]

Do a compression test. See if the air squirts out of motor oil room, or if it leaves the carb/exhaust. If the valves doesn't close properly, you'll lose a lot of compression, that's what happened to my Honda 250 TWIN!

[@user-xz9gk8tl1k]

I bought a new carb for my vlx600 I check the jets and bought a kit from y'all but it all ready had a 50 pilot and a 145 main but a 50 is bigger than a 48 right

[@TJBRUTALCUSTOMS]

Yes. 50 is bigger than 48.

[@marcusjohnson1487]

99 shadow 600. Aftermarket exhaust cv40 carb. Bike starts runs at idle the exhaust after fires like a shotgun.. ear ringing loud.. I can't figure out why

[@TJBRUTALCUSTOMS]

put the stock carb back on.

[@klownization]

So what does a coughing carburator mean? Is it just dirty or to lean or is that what they call a backfire? It is not coughing on decel but on steady rpms

[@SouthernGamer24]

My bike does the same thing, at steady high rpms, it pops and then dies while im riding. Did you find a solution?

[@rockyesterline7942]

After I put on my new pipe on my New 2022 Honda 450RL back fires out the exhaust when I let off the gas!! only one mile on it !! They said you need to put on a vortex ECU will reset the fuel injector ,air fuel and ,timeing' still waiting for it to show up it's been one month and a half they are hard to find becouse everybody wants them and are $800!! i did replace my copper gasket in the head that not any one on Utube has put on in any of there videos yet!!

[@TheVag98]

Hello everyone and TJ customs. I took out my carbs today Honda steed 400 cleaned them, put them on again with new boots etc. Problem is I adjusted my air fuel mixture so no more after firing which is good but after a hard acceleration and a cut back to idle engine seems to die out and can’t keep idle. Nevertheless as soon as hit the starter starts right up. Any possible explanation please? Thank you

[@TJBRUTALCUSTOMS]

That sucks man, but I'm sorry we just can't diagnose bikes in the comment section. We do have an e-book that has a ton of tuning information which you'll need- shoptjbc.com/blogs/news/performance-tuning-book-lp

[@tantuongnguyen851]

How to prevent gasoline from flowing in the exhaust pipe of a motorcycle 2008 Honda shadow 750

[@camdencrotwell349]

Is it ok if it does backfire a little bit like little quiet burbles or I should say after fire is it unhealthy for the bike? Cause I do kinda enjoy the pops

[@TJBRUTALCUSTOMS]

not great. keep tuning👍

[@joecader]

What about FI bikes?

[@rajnikantpatel6316]

lean mixture cause rpm rising possible? without accelerated some time rpm is increase it self,lean mixture screw cause problem possible?

[@rajnikantpatel6316]

@Ruff Justice thank s..

[@Tacbi0325]

Hey bro please help me ... I send a question u never answer

[@johnhales716]

I have a BAD afterfire from the front cylinder and the exhaust pipe stays cold. I try to adjust the air fuel mixture and the only outcome is a bigger BANG. I just got done installing jet kit, velocity stacks with the smallest jets and 1 washer like in your video. Any suggestions? The other cylinder responds fine.

[@61zachary]

John Hales mine is doing the same thing!! Figure it out yet?

[@johnhales716]

@@61zachary not yet still working on it

[@carsandclutch5793]

My bike idles fine but does pop back through carb while holding at steady rpm and occasionally pops back through exhaust 2002 spirit 750 doesn’t do it if my choke is slightly on

[@deejarvisful]

If the problem goes away with the choke slightly out, then one or more cylinders is running lean.

[@jevoneverett8549]

I recently put a vance and hines exhaust on my bike and the back one is after firing? Any input? Thanks in advance

[@pappydanny58]

I have the same setup and the same problem. Any luck?

[@hamishdow2188]

Anytime you tinker with the exhaust or intake rejet accordingly

[@pappydanny58]

Finally found a rejet kit with everything I need www.ebay.com/itm/333592756516

[@Videometh]

Off topic but will the vt600 hardtail kit work for the vt750?

[@Videometh]

TJBRUTALCUSTOMS okay thank you!

[@Basement31]

Any major damage if a bike owner doesn't fix his after fire issues right away??

[@Basement31]

TJBRUTALCUSTOMS thank u for replying. Will keep that in mind!

[@TimothyIpmanchilds]

Dude your awesome ...... Now " ok google " who can fix my carb near me. Lmao Carb sound like it spits and backfire ONLY deceleration or holding one speed 30 - 40 - 50 - 60 - 70 ONLY or on deceleration.

[@Penguin32880]

What causes afterfire on acceleration? 2001 ace deluxe 2. Bike idles great, quarter throttle is okay(kind of sluggish) anything past quarter throttle and the bike afterfires.

[@jeffbatchler2899]

This sounds like a slide needle problem. Shim needle or unshim. Dont change the factory slide spring or needle

[@Penguin32880]

@@jeffbatchler2899 thanks. It's almost like a misfire. I just changed plugs

[@jeffbatchler2899]

@@Penguin32880 what mods are done to the bike as far as intake and exhaust.

[@Penguin32880]

@@jeffbatchler2899 stock intake. Vance and hines pipes.

[@jeffbatchler2899]

@@Penguin32880 jet sizes should be 105 front 108 rear and a 40 pilot jet from factory. These hondas are picky on the air fuel mixture. Too much air will give popping on acceleration, too much gas will give fireballs or black smoke on acceleration. When sitting idle and you rev it up in neutral do you notice it as bad while revving? Or more under a load?

[@travisjohnson1277]

What if someone cut the pipes off about half way?

[@travisjohnson1277]

@TJBRUTALCUSTOMS i bought a back from a guy online its a Honda vt750 shadow and when i ride it ill be going up the road and when i get on it and wind out the gear right about the time im winding out it begins to cut back and sputter . The pipes are cut off about 1 and maybe 1/2 foot from the block could that be causeing the cutting back im experiencing??

[@travisjohnson1277]

It seems like im getting air back into my engine

[@travisjohnson1277]

Running lean thats not enough fuel to carb?

[@blueberryboyz2485]

So is this bad for your engine life

[@HoChiMin88]

So what's the solution lol

[@TJBRUTALCUSTOMS]

Tuning.

[@dicktrickle4197]

AFTERFIRE RACING who's got it

[@bryanmiller5074]

Not true... it has 2 due with air going into exhaust... igniting unburned fuel !

[@Tacbi0325]

Please

[@starzanhorse4758]

ok, afterfire now what?

[@zachmunz4907]

nah

[@kennypool]

Blah blah blah with crap audio.