1989 sportster 883. Carb clean with good jetting, diaphragm in perfect condition, manifold seals changed, plug and plug wires changed. I haven´t check coil and ignition timing yet.
I had this problem untill yesterday. I toke out my carb and my intake manifold. Check if that is bent. Or has high spots (if you do sand it down cause air can seap thru) Check if the flanges are bent.(sand off all dirt and all pieces of old rubber) If they are bent get new ones. Place new seals (use bearing grease to make the job easier so they stick) handtighten the manifold (dont tighten) place the carb and airfilter. Now you can allign your manifold (if you dont you might misalign) take carb off again and tighten the manifold. Half a turn on each bolt. Else you comprimise the seal on one side. When its good and tight. Replace carb. And air cleaner. And enjoy your bike. Bit of work but easy to do by yourself. Just have to be patient. Prob have to take off fuel tank seat and horn assembly aswell. If you doubt you can put it back together just make pictures of what you do. Takes about 2 hours. Maybe 4 if its your first time.
OK I know this is an old video BUT I finally figured out the main problem with my 2006 harley 1200 custom... the spring that operates the accelerator pump was weak so it was not shooting enough gas when i would chop the throttle. I was watching it and it barely had enough tension to properly open that valve. I shimmed it with some tiny washers and my bike only pops like once or twice for like the first 10 seconds of idling i couldnt get it to pop once i was riding after a min of the engine warming up. If you have messed with jets and needle position and the air mix screw check that fucking spring dude!! Hope this helps!! It took me like a month to figure it out.
1997 Sporster 1200C. Same thing. New plugs, CV Permorance fuel mixture screw, and rebuilt the carburetor. I had to tune the carb on the rich side because the intake has a slight leak. Runs fine for now.
Your intake seals are wearing out. The poping is air coming in from the weakest points on the worn seal. Oxygen is added to the mixture, on a deceleration of RPMs. More oxygen to the mixture makes it sensitive igniting itself where the leak is and burning everything through the manifold. In some cases smoke will burst.
An air leak can cause this. I had to put a quality automotive hose clamp where the carb meets the intake manifold. I tighten it with a long 5/16" wrench from between the cylinders on the other side. It fixed my leak real well.
Videos and forums say timing needs adjusted. Air fuel mixture, low fuel pressure and or fuel filter. Also intakes and exhaust pipe sizing difference could cause backfires. One video on youtube shows how to adjust timing with a clear window plug, timing light, and a adustment of the pick up plate and sensor under the cover on the right side of the harley evo sportster. A lot of Harley's are probably similar location of timing port and ignition spark pick up sensor.
This Is a Lean Spit. Things to fix it. Check intake gaskets. If they are OK then look at you idle Jet. it is a stock 45 jet on a twin cam but sportster may be smaller. Buy some larger idle jets and keep upping the size till it goes away. Sea level should be 48 to 52 on a 88 twin cam.
My 04 does the same thing. Almost a hiccup at low rpms when u start to hit the throttle. I changed plugs, air filter, and ran some sea foam through a couple tanks of gas, but it hasn't changed yet. It does seem to get better once it's been ridden for a few minutes, but still occasionally happens. I thought the carb was gummed up, the only thing left that I can think of is the fuel filter...
Don't put sea foam in you're bike. It's not for them. .. strip and clean you're carb. Use a good kit from James gaskets. You'll get everything you need. Everything. Then use Carb " cleaner carefully on jets etc. Seafoam is Not for bikes.
@@michealharrelson2192 when it was sputtering and backfiring i couldn't even ride it. I did a full carb rebuild, replaced spark plugs, replaced coil. Still wouldn't run right. So i read some threads online and watched a few videos and decided to play with the gapping. It may be important to not that im running a mikuni carb and drag pipes. As i changed gaps it got better and better. I was fouling plugs about every 6 weeks since gap change its been almost a year and haven't had to get new plugs yet.
It does it, becouse of the factory dual fire ignition sysrem. Both sparkplug give ignition at the same time, so one of them gives spark when its not nevessary, and this spark ignites the air fuel mixture when the intake valve is open it can came back to the carb. Single fire is better, altough i think its not worth trouble converting it, dual fire just works fine, most hd riders can live with some bacfire... Put on the air cleaner cover.
Remove the plug that covers idle mixture screw. Turn counterclockwise 1/2 turn. Also noticed your cam chest is way to noisy but that's not causing pop out of carb
I have an '05 that did the exact same thing. I changed the intake gaskets and adjusted the idle back up to 950 rpm per the shop manual and it went away. Most sportsters do this and sometimes these parts fix it and sometimes they don't. I guess that's why the dealer doesn't want to fool with them.
I know this was 9 months ago but how did you figure out it was the ignition pickup and ECM? Is there a test for these? Mine has a similar issue.... had head gaskets replaced and crank position sensor.....
Hi Mate I know this was along time ago My sporty is doing exactly the same thing a 96mod I tried all the simple things first carb kit inlet manifold seals plugs coil leads looking at ECM next Can I just ask you did your bike only do it at Idle did it run fine the rest of the time because that’s what mine is doing just the intermittent miss sometimes reving it from idle I would really appreciate any feedback
@@joshuaread8431 Did you ever get yours fixed, mine is doing the same thing. exactly as you described, very intermittent and only when cracking the throttle from idle. would appreciate your feed back. Thank you
Yeah mine does the same thing if I don't let the engine warm up first. Especially on cold days. Once it's warm no problem. I assume it's normal just let it warm up for s couple of minutes before you ride it and you should be all set.
Could also be, jetting, lack of back pressure or bad fuel and the other few things posted..FYI, every time you change the exhaust you need to check jetting and may have to re jet..
Doug Schwarz - Sorry I'm new to working on a Harley myself. I picked up a 81 iron head 1000 Sportster so, the very little I do know is centered around that year. I would be guessing and I'm sure you already checked your clutch cable and made adjustments and checked trans fluid/gear oil level. Sorry I couldn't be of more help but, I don't want to steer you wrong.
I have the same issue with mine someone I bought it off of sayed cause it has a black gas tank and if u have it set for a while and don't drain the gas out of the tank and carb b4 u store it it does that was he right?
I had this problem untill yesterday. I toke out my carb and my intake manifold. Check if that is bent. Or has high spots (if you do sand it down cause air can seap thru) Check if the flanges are bent.(sand off all dirt and all pieces of old rubber) If they are bent get new ones. Place new seals (use bearing grease to make the job easier so they stick) handtighten the manifold (dont tighten) place the carb and airfilter. Now you can allign your manifold (if you dont you might misalign) take carb off again and tighten the manifold. Half a turn on each bolt. Else you comprimise the seal on one side. When its good and tight. Replace carb. And air cleaner. And enjoy your bike. Bit of work but easy to do by yourself. Just have to be patient. Prob have to take off fuel tank seat and horn assembly aswell. If you doubt you can put it back together just make pictures of what you do. Takes about 2 hours. Maybe 4 if its your first time.
Thank you I'm going to try this
@@LoRdOfCoRpSeS Hey, did that work?
@@digitalonscreen9076 I took off my gas tank to make this a little easier and it was pretty simple. So far it seems to have worked!
OK I know this is an old video BUT I finally figured out the main problem with my 2006 harley 1200 custom... the spring that operates the accelerator pump was weak so it was not shooting enough gas when i would chop the throttle. I was watching it and it barely had enough tension to properly open that valve. I shimmed it with some tiny washers and my bike only pops like once or twice for like the first 10 seconds of idling i couldnt get it to pop once i was riding after a min of the engine warming up. If you have messed with jets and needle position and the air mix screw check that fucking spring dude!! Hope this helps!! It took me like a month to figure it out.
1997 Sporster 1200C. Same thing. New plugs, CV Permorance fuel mixture screw, and rebuilt the carburetor. I had to tune the carb on the rich side because the intake has a slight leak. Runs fine for now.
Your intake seals are wearing out. The poping is air coming in from the weakest points on the worn seal. Oxygen is added to the mixture, on a deceleration of RPMs. More oxygen to the mixture makes it sensitive igniting itself where the leak is and burning everything through the manifold. In some cases smoke will burst.
An air leak can cause this. I had to put a quality automotive hose clamp where the carb meets the intake manifold. I tighten it with a long 5/16" wrench from between the cylinders on the other side. It fixed my leak real well.
Videos and forums say timing needs adjusted. Air fuel mixture, low fuel pressure and or fuel filter. Also intakes and exhaust pipe sizing difference could cause backfires. One video on youtube shows how to adjust timing with a clear window plug, timing light, and a adustment of the pick up plate and sensor under the cover on the right side of the harley evo sportster. A lot of Harley's are probably similar location of timing port and ignition spark pick up sensor.
This Is a Lean Spit. Things to fix it. Check intake gaskets. If they are OK then look at you idle Jet. it is a stock 45 jet on a twin cam but sportster may be smaller. Buy some larger idle jets and keep upping the size till it goes away. Sea level should be 48 to 52 on a 88 twin cam.
Change plugs
Make sure coil and ignition is working on both cylinders
Clean carb
Check gaskets
Make sure fuel petcock isn't clogged
Fuel lines good
My 04 does the same thing. Almost a hiccup at low rpms when u start to hit the throttle. I changed plugs, air filter, and ran some sea foam through a couple tanks of gas, but it hasn't changed yet. It does seem to get better once it's been ridden for a few minutes, but still occasionally happens. I thought the carb was gummed up, the only thing left that I can think of is the fuel filter...
try crankcase sensor
H2O FLuX you ever get this fixed? What was the problem?
Don't put sea foam in you're bike. It's not for them. .. strip and clean you're carb. Use a good kit from James gaskets. You'll get everything you need. Everything.
Then use Carb " cleaner carefully on jets etc. Seafoam is Not for bikes.
I have a 96 xl1200c. It was doing the same thing. I put new pugs and played with the gapping. Runs perfect gapped at 42.
Okay could you get your bike over 75 MPH
@@michealharrelson2192 when it was sputtering and backfiring i couldn't even ride it. I did a full carb rebuild, replaced spark plugs, replaced coil. Still wouldn't run right. So i read some threads online and watched a few videos and decided to play with the gapping. It may be important to not that im running a mikuni carb and drag pipes. As i changed gaps it got better and better. I was fouling plugs about every 6 weeks since gap change its been almost a year and haven't had to get new plugs yet.
It does it, becouse of the factory dual fire ignition sysrem. Both sparkplug give ignition at the same time, so one of them gives spark when its not nevessary, and this spark ignites the air fuel mixture when the intake valve is open it can came back to the carb.
Single fire is better, altough i think its not worth trouble converting it, dual fire just works fine, most hd riders can live with some bacfire...
Put on the air cleaner cover.
Remove the plug that covers idle mixture screw. Turn counterclockwise 1/2 turn. Also noticed your cam chest is way to noisy but that's not causing pop out of carb
I have an '05 that did the exact same thing. I changed the intake gaskets and adjusted the idle back up to 950 rpm per the shop manual and it went away. Most sportsters do this and sometimes these parts fix it and sometimes they don't. I guess that's why the dealer doesn't want to fool with them.
Could possibly be one of these two things:
1.Bad crank position sensor (easy to replace)
2. Intake manifold seals need replacing
No no...
My sportster is consuming fuel rapidly and backfiring into the carb, suggestions? And no it’s not leaking out the overflow
I know this was 9 months ago but how did you figure out it was the ignition pickup and ECM? Is there a test for these? Mine has a similar issue.... had head gaskets replaced and crank position sensor.....
Just curious was the bike sitting up a long time previously to this happening?
We still wondering lol
Finally I fixed the problem. it was the ignition pick up and the ECM.
V
Jon Makina , how did you fix it ?
Hi Mate I know this was along time ago My sporty is doing exactly the same thing a 96mod I tried all the simple things first carb kit inlet manifold seals plugs coil leads looking at ECM next Can I just ask you did your bike only do it at Idle did it run fine the rest of the time because that’s what mine is doing just the intermittent miss sometimes reving it from idle I would really appreciate any feedback
@@joshuaread8431 Did you ever get yours fixed, mine is doing the same thing. exactly as you described, very intermittent and only when cracking the throttle from idle. would appreciate your feed back. Thank you
@@christopherjones7092 did you fix yours mine is doing same thing
My bike is now making a click sound after a rough start where I didn't pull the clutch to start.
try the crank shaft position sensor. it times the spark and fuel intake. cheap and easy to do yourself
Yeah mine does the same thing if I don't let the engine warm up first. Especially on cold days. Once it's warm no problem. I assume it's normal just let it warm up for s couple of minutes before you ride it and you should be all set.
Common sense which this guy has none
Its called the sportster hiccup . Almost all of them do it. Mine sometimes and I think its the dual fire ignition.
Christopher Skeen I have a single fire and mine does it also. ?
I covered the holes someone put in my breather and only run high octane with the ethenal and it only hiccups when it's cold lately.
So...your under the impression that this is normal...???
@@jerryking1434 i am , but im no mechanic. I was told you could put new high performance ignition and might fix it.
have you checked the vacuum or power to the VOES just behind the carb.
My bike does this and it has been sitting for along time
Ny older one does that when running lean, inrich a little and it goes away.
Can you please share more information? How did you fix this?
Could also be, jetting, lack of back pressure or bad fuel and the other few things posted..FYI, every time you change the exhaust you need to check jetting and may have to re jet..
Cyclo TeChTwIsTeR My 2000 sporty won't go into 1st gear without a grinding noise
Doug Schwarz - Sorry I'm new to working on a Harley myself. I picked up a 81 iron head 1000 Sportster so, the very little I do know is centered around that year. I would be guessing and I'm sure you already checked your clutch cable and made adjustments and checked trans fluid/gear oil level. Sorry I couldn't be of more help but, I don't want to steer you wrong.
It's a Harley ! POP ! POP ! $$$ POP ! $$$ Again !
Mine is doing the same thing!! What's the fix? Thanks!
MyDrummerjoe iv
I have 05. 883 it does same thing
Mine 04 ...Does it too...Sportster hickup.
I have the same issue with mine someone I bought it off of sayed cause it has a black gas tank and if u have it set for a while and don't drain the gas out of the tank and carb b4 u store it it does that was he right?
Yeah it has to be warm, the carb has to be warm or they fart/pop and back fire, nature of the diaphragm carb.
My FLSTC backfires when cold and doesn't when it's warm so you gotta be right.
Sportster 2004... Idem...😢
Its a older bike....time 4 a carb rebuild
mine backfires when I ideal it down or cruise with low rpms. could it be the exhaust gaskets??
gebroni brothers I don't know, but mine does the same thing. And I have an S&S super E
@@motoadventuredude Ik this is a little late but..
czcams.com/video/eSky1ZfHdhA/video.html
I think it might be the points
Ignition timing is all screwed up
I have a 1974 1000 xlh at 65 or 70 mph it cuts out , why
Gator Stimson too old lol
Points not advancing perhaps
Es igual a la mía!!!
Bad intake seal
Carb jets
Clean your carbs my brother
Is it Palestin flag ?!
BTW ... thanks for sharing the solution..
you're a fucking moron, profiling a person because of his name, you go away fucking peice of shit
Needs more air less gass
What would make your bike pop while riding down road
Marshal Wilkinson lots of chrome and a custom paint job.
@@stoneyswolf God damn
Trop riche en essence .... Tu as trop d arrivée d essence ...
Desserrer un peu la vis de richesse sur la carbu tu dis ?