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HOW TO TUNE A CARB / CARBURETOR (step by step guided)

Jul 02, 2021
whats up guys today we are learning about

carb

uretors everything you need to know about them how to adjust them what each component does how to install i am going to show you all this can be a very confusing topic adjusting the

carb

uretor but it isn't it has to be if you understand how works one of these spray bottles then you can understand a carb all we are doing is making the perfect mist inside the carb let me show you exactly what i mean i spent a lot of time and effort these little diagrams are made for you y'all teach them how to

tune

their carb so if they could turn back turn to the subscribe button and hit the little blue bell right on the side so they can get notified when new videos like this come in. off let's get started let's

tune

up this gy6 honda ruckus it has a slider style pwk carb it doesn't matter if you have a motorcycle an off road vehicle it doesn't matter if it has a carb these concepts will apply there are a few terms you need to know when it comes to carbs just because if you are talking to someone or if someone is talking to you about carbs then they will be on the same page so lean would not be enough fuel characteristics of a lean condition in a carb would be a quagmire you go to full throttle it's like it's too lean not enough fuel stoic that would be perfect the carb is running absolutely perfect with no hiccups and then rich rich means too much fuel so when you go to give it gas it's going to be like it's going to cough , sizzle and such, the opposite of swamp lean underfuel so lean underfuel stoic or perfect rich too much fuel so i have the carb completely taken apart by the way this is a pwk slider style carb we are working on all the parts have been broken down and labeled so i can tell you what they are called what the functions of each are part and then we can put it back together and you'll know exactly where all the parts go what they do and then we could dive into what components we need to change to make the carb work absolutely perfect so this is our carb body it's a completely stripped down version from the carb that we have i removed all the components i'm going to go

step

by

step

and show you exactly how all these components go on this carb so this is a pilot screw or an air fuel screw i'll show you what i mean in just a second so you have the screw, it's like a tapered looking screw and you have a spring that goes in there, the spring is there so it doesn't vibrate, basically you can call it a pilot screw or an air fuel. screw if it is an air screw that small part where you install this pilot screw or air screw is going to be on the side of the air filter if this screw is more on this side it is going to be a fuel screw the easiest thing to call is a pilot screw the more you back it out if it's an air screw it's goi I mean you'll give it more air it's a fuel screw the more you back it you'll give it more fuel so we'll install that a good benchmark would be to tighten it until that is slightly settled. so i just set it down slightly and you're going to turn one turn one and a half turns two turns for sea level turn two and a half turns for high altitude that's just a general setup you can set right away the box that doesn't its concrete at all i'll show you how to adjust that in a moment next we have the idle screw this is pretty self explanatory this controls the idle so you have your little washer that slides right in there and then you have your spring again the spring is so it doesn't vibrate this just installs on the side like this and you can't really get this assembly you'll have to apply a little bit of pressure as it has the spring you can't get this assembly until it's make sure you don't remove it it's a real easy finger screw you can't set this until you actually start the engine so I just do a few turns there and that's the idle screw Next, we have the choke.
how to tune a carb carburetor step by step guided
Pretty simple choke goes in and out like this. engine won't start when cold you pull the choke a lot of times on this style of carb you won't even need these let me show you how it goes in right on top of the carb you will see the little spot because it's pretty obvious because it has the threads you just match them up and just you take it down this is 14mm just get it nice and snug it's plastic so be careful we've got the needle jet here and the emulsion tube sometimes these two are together if they are together this complete assembly will be called a needle jet but since it is a two piece arrangement this is our needle jet and this is our motion tube this is the part we always It ends up on the floor people don't realize it's a two piece deal and let me show you what So the way this goes in see that rounded part that's going to be facing down into the bowl so so so if i drop it in there like that and pull out my tube of emulsion, you won't realize it's two pieces. and then it just falls off that's the reason you just have to be careful so again the end of the machine will go down to the point every time I look through the carb if I look down at the carb then it sticks out if I you did it any other way it won't open so make sure you do it the right way very important so emulsion tube or jet holder i'll show you why it's called a jet holder in just a second come back right where we drop it the emulsion tube in it locks that suction cup in place so i'm just going to turn it down so it looks like this and i need to turn it down with a wrench so let's go ahead and make this a nine millimeters, just tighten it. not like a serious titan because this is brass it will come off very easily next we have the main jet this main jet goes right into the jet bracket of course so it threads in as well and this is the 6mm .
how to tune a carb carburetor step by step guided

More Interesting Facts About,

how to tune a carb carburetor step by step guided...

I just tighten it just right and this is where our fuel will go. now a lot of people get confused about what a jet is i mean you think a jet are you thinking like a plane or something weird a jet is basically a screw like this with a hole drilled through a very precise hole so that's our main jet this is going to control three quarters of the throttle to open it all the way then we have the pilot jet this controls the idle and it just settles into this circuit again your carb may be slightly different but the concepts remain the same so again a the jet is basically a screw with a very precise drilled hole the pilot jet will look a little different than the main jet as you can see and then you just adjust these they are just brass so no need to really get the heck out of them just to dive into these jets as this is the most talked about part in any type of carb adjustment is jet this is the pilot jet e he pilot jet can be called an idle jet can it be called an idle circuit pilot circuit there are a few different terms but the end result is this skinny pilot jet that controls idle to quarter throttle and then you have your main jet here and that's going to control the three quarters throttle at wide open so there I'll teach you about the rest here in just a second but on the sides of the jet you'll find a little microscopic number and that refers to that jet size so if you need to go up or down if you're thin or rich you can do it lets say you had a jet 120 and it's too thin and you needed to enrich it a bit then you like a jet 122 just for reference so this is kind of a unit that needs to be assembled within itself . we're not going to do a wire to be a little bit different but this is our nee dle jet the needle jet is going to control quarter throttle to three quarter throttle so this is like your main cruise circuit so what i'm going to to do is take the slide this is called the slide i'm going to drop the needle the spout needle just like that and then you've got your cable lock or sink spring seat it'll go down like this so you've got your spring if i push it down below you'll see what I mean look at those kind of locks you can do it backwards like this then it doesn't go all the way down so make sure it's the right way it will slide down very easily and then you have the top of the wire here so cable top cable cap whatever you want to call it then normally you would have the throttle cable coming up the top and it will lock up there let me show you how this goes into the carb they are like blocks when or you're a kid you have to line it up so that at the same time the needle has to go down the needle jet hole you'll find out you'll know what I'm saying and if you do it yourself but I'm going to drop it obviously it didn't get caught because it fell all the way down since it's spring loaded i have to push the cap down i'm just going to hold it down with my fingers like this and then you can get your screws to start again normally your wire would go in from the top here so I'm going to make it start by hand and then just rotate it down so it doesn't. coming loose so we've pretty much put the carb back together completely but there are a few more components we need to put on the bottom here so we'll go bottom up so this is the float bowl drain. your float bowl works like a toilet if you know how a toilet works this would be like the tank behind your toilet where the water is held so i'm going to the cool thing about these carbs is if i pull the drain from the float bowl i can get to the main jet which is great since i don't need to remove the whole float just tighten it good and refit this is the drain for the fuel so it's normally one piece i just took it apart because i wanted to show you how did the two pieces come together this is his float imagine the back of your tank in your toilet how does that work if you know how that works that is going to be the same concept so you have your float pin which is this guy and then your needle what is this let me show you how it works on the carb here is the float needle if you notice there is a little button right there if you had a clogged carb that button would not push but what i have to What to do is drop it on the float so see how that works and then I'm going to drop this down I see I have this at an angle so it doesn't slide off the float.
how to tune a carb carburetor step by step guided
I'm going to drop that like this and line up those holes because that's where the pin goes. I'm going to go I'm going to slide my pin in there just like that and that's how the float works if I go up and down like this the float needle goes up and down and as you see this carb is on the right side so that when gasoline comes in, there's a cap on this, but when the gasoline gets in and flip it over like this and take out the float canister the gas goes down through this hose right here through this valve right here where the float needle is at as you fill this float bowl the gas will start to make this float float when it floats up it's going to kill the fuel so see where that is on this line here with the line on the carb this is the proper setting that you need, the final step is to install the float bowl onto the carb so you just align it. going up sometimes it's a little tight and difficult it goes on like this and then of course two screws hold it down then you have the hose for your power jet there's a little jet in here and when you open it all the way open it all the way open if you notice it getting fuel fr move the flow bowl up to what they call the power jet and see that little hole there that little hole feeds fuel at wide open throttle it won't start coming out of there until it's wide open and that's a complete carb we just put together you can use this to clean your carb too now that you know it goes together for reference this is how the carb mounts it has your air filter attached and goes into your intake manifold it mounts to the actual engine and then of course the throttle cable goes in at the top.
how to tune a carb carburetor step by step guided
I know what you're thinking. There are many components to a

carburetor

, but at least now you know what each component does. Where are you going. how it looks Now I can show you how. to tune a

carburetor

let's do it now that you know what a pilot jet is pilot screw jet needle and main jet let me tell you what they do so you have your pilot jet that will be completely idle at 100 percent throttle closed to quarter throttle open the nice thing is you have the pilot screw or the air fuel mixture screw you can adjust it in or out to get that perfect idle once you have that perfect idle you can adjust the throttle screw true idle down so that it is at correct idleyour jet needle which is going to be your main set point will be quarter throttle to three quarter throttle which will be like your cruise circuit your jet needle then you will have your main jet which will be fully open three quarter throttle to wide open wide open, all of these circuits overlap each other, so it is very important that you only make one adjustment at a time.
I always start my carb adjustment with the pilot jet. so you can get it to idle perfect then I open it wide you might stumble and spit on the way up but if you can get it wide open then you know your main jet is kind of close and then I start working on my Needle jet, cruising speed, if you can dial all of those perfectly you will have a perfectly working carb to get to your jets. If you are just doing your main jet, you can remove the drain from the float bowl and it can go directly to the main jet without removing the entire float bowl.
You need to be careful with these float canisters if you have gasoline. this o-ring could swell and it's hard to put back on so your main jet here is going to be for three quarters of the throttle fully open to fully open so you have your main jet here this guy that's going to be three quarters throttle to fully open then you have your pilot jet sitting right next to it it's kind of dipped down there that's going to be fully closed down to quarter throttle remember you can adjust your air fuel mixture in your circuit idle you can adjust it in or out if you hit the point of interest not where you are halfway like you only have a half turn until you bottom out then you will have to change your jet, if you back more than three and a half turns then you will have to. change your jet that's the range from a half turn to three and a half turns now your needle will have to pull that out i showed you how to do that which is inside the slide if you notice your needle has little grooves i have a drawing here these little ones slots you have to decide where you want to place your clip depending on the slot if you go up or down on the needle it's going to make it thinner or richer so if I go higher up on the clip the needle is going to go down which makes it more thin if I make the clip go down towards the bottom here then the needle is going to go up which will make it richer.
You can buy different needles with different angles of this needle. Very subtle difference in the by eye but that makes a difference too so you can play with I'm not going to go too deep into those needles that's more for super fine tuning one huge thing to know is that the jet It's always different, it doesn't matter if you have two identical bikes, the jet will usually always be different. you're going to be pretty close based on your friend having the same bike same jet but yours is going to be a bit different, I don't care if it's a little air screw tweak, a total main jet change, It's always going to be different, so you can get a reference online, but that's not going to be the concrete answer.
Lift and performance intakes, such as air filters. get a new intake or if you went up from california to colorado or the altitude tire where they have less air this all plays a huge part so you need to be constantly jetting and stuff that's why electronic fuel injection its so big deal nowadays technology is stuck a carb its basically a tape deck compared to an mp3 they still work great but you only have four circuits to tune unlike an efi system they have about 30 circuits to really tune you can dial them in and it's all electronic like i told you i got this fuss here let's tune it i'm going to put everything i taught you into action and you can see exactly the sounds it makes what happens and how i do the adjustments let's make it a very important thing that should check before you start you should have throttle freeplay, turn the bars left and right to check your throttle r is not being pressured in any way. you should have a couple of millimeters play when you turn the bars left and right so you know the cable doesn't pull the carb up so we have our new carb here this hasn't started yet so I assume we're going to need to do some safe idle adjustments and tighten our air fuel screw.
This has a choke. I'm going to try not to use it too many times in this style of setup. You don't need to use the choke. see if i can get it to turn it on i might have to keep it alive with the throttle hand throttle at first and then i'll adjust the idle it's actually decent so if i turn this on it will increase the idle like so now this is our adjusting screw air fuel air fuel I'm going to turn it in or out it's getting worse so I'm going to go the other way until I get a nice smooth idle it's going to go up if you notice there's a sweet spot here so kind if find that mid range and then the idle is normally too high like it is now i'm going to lower this and again i didn't use the choke at all so that's ok maybe a little higher at an idle on this particular model the gy6 you wanted from 1800 rpm to 2000 i'll let it sit here and it'll fully warm up probably five minutes before doing a nothing else so it's ok and it warms up now if i give it a handful of throttle if there's swamps like that , in general it would be a lean condition that right there is a swamp which is normally a poor condition if it was a rich condition you get like a stumble like it wants to speed up but it's not but it's kind of a guessing game the noise that you were hearing is a rich condition that it stumbles into like that so we just want to start at the bottom and work our way up into the tune so let's go for a little walk we can see if we dial the main jet first, we have the inactive jet set up by ear very well, we are inactive, things like that, but how is it going to be?
When we open wide and then adjust our cruise speed okay let's see what we got so this is just quarter throttle that will be in my idle circuit. I'm going to roll on this and see if we can get our uh so that our true velocity is defined. acting safe it will be our needle so that sounds great right now as you are sitting our idle jet is nice it feels good by ear our cruising speed needs attention so that will be our needle and then our main jet which also looks pretty good so it's not tripping it's not stalling so all of our focus right now will be on the needle left quarter throttle quarter throttle turn this piece around of a quarter acceleration.
I've got a haze right there, I can feel it on my seat throttle, no backfiring, so if you noticed that every time I ease off the throttle when I'm not giving gas, I'm slowing down or downshifting, I don't get any backfiring. if it backfires on me then you know i would have to go bigger on the pilot plane because backfire is poor condition alot of people think its rich condition but its not now if i stop and my idol is hanging as it stops it's like and then it slows down and goes down so you know you need to make your pilot jet bigger you need to make your pilot jet bigger or sometimes you can adjust your air fuel screw to correct that so the range It kind of sits like a rich condition so it wasn't a swamp where it didn't just like to die out but it was more of a stumble a swamp would be more of a lean condition there wouldn't be enough fuel and a rich condition would be a stumble like you heard so it's a bit of a guessing game if you're not running something called a wideband o2 sensor which makes life super super easy if you want to get the spark plug out and you can verify that you can cruise on it at the rpm you're acting and then you can pull the spark plug and look at the tip of the spark plug and if it's really black it's very rich if it's really white it's thin and if it's tan then it's stoic it's perfect though with all the fuel additives make it very difficult to do plug reads like that nowadays let me show you what i am Talking about this broadband that makes your life so much easier no guessing so this is the mobile key.
The wideband O2 sensor comes with all the cables. It comes with a wideband O2 sensor. This is welded onto your exhaust. it has a cap for the o2 what it does is it reads the exhaust gases it sends the signal to this gauge this gauge fits it spits out a number and that will tell you exactly what your air fuel mixture is so i'm going to hook this guy up and then we'll be able to tell exactly if we were rich or lean no guessing which by the way can be found on our website i'll put the link below and you can buy one of those let's talk afr ranges afr means air fuel ratio this it's your operating range for running so while your bike is running this gauge will show a stoic number it's chemically ideal this is just like if you had a factory car or motorcycle or whatever this is going to be set normally to 14, 7 that's good it will run perfect across the board now if it was over 11.5 which is more fuel it will run even better that's for performance someone will boost it again for the performance your number is anywhere from 11.5 to 13.3 for performance now if you just want fuel economy then it will be at 16.5 now this number as you drive you will adjust your carb at all the circuits I told you about so that number is right where you want it to be based on what you're interested in, um economy of performance or just chemically ideal.
I have my wide band welded onto the exhaust with the plug supplied. Many exhausts will already have this plug installed. the factory and just hooking up the wires this is totally a temporary thing because i'll take it off when i'm done tuning i got the meter in there then i got power up to the slow charger this takes all the guesswork out of thi s worth the investment if you're doing any sort of adjustment on a regular basis otherwise you can do it by ear so I'm going to adjust the air screw, the air fuel screw, I'm taking it back right now we're going to go a little bit at a time the more I back it up the leaner it gets I almost got it back four turns that won't work that tells me we need to get down on pilot but I'll bring it back when I I introduce it gets rich it's as good as what we're going to get with that pilot and remember the pilot circuit is purely for idle I put it on the bars here so we can easily see it so there's our little guy after quarter totally rich we're at 10 afr ok so we're on our needle right now 4.5 up and now we're going to get in our main main jet was even at 10.5 see how a broadband can help you now we know they're super rich and across the board so we need to go a little less on the pilot a little less on the needle and a little less overall you just want to do this one at a time but since I know what I'm doing I'm going to do all this at once and revisit so i need to loosen the boot so i can get this carb out. it comes off pretty easy remember it's full of gas so the minute you tip it over it's going to start spilling gas what I'm going to do is open this drain here and then drain it on a rag. the gas goes to the rag there we go and this is how we drain the gas from the canister so we can continue to remove the canister because remember what i said is there is an o-ring in the float canister gasket that can warp and is hard to come back going to go in if you put gas on it so we always want to drain the gas first it's a great thing you can go straight to the main jet very easily as this is like a race style carb a lot of times when you go racing.
You're always changing those main jets because you're always wide open on wall balls when you're racing so the main jet is t The main circuit would be changing so I made it easier to get to that but I can't get to my pilot or anything like that, so the whole vessel has to come out. Get this floating container out of here. move that. By the way now we can get to our pilot plane and main plane we're going to make it a little bit smaller this is kind of trial and error so we're going to make it a little bit smaller on the pilot a little bit smaller on the main jet then when we're done with that we'll open the needle and move the needle clip just a little bit the pilot jet was a 38 this is a 35 many times that's how they'll go in like three step increments but we went smaller , this should be perfect, perfect, perfect and we can adjust it with the air screw.
We'll do the same thing on the main stream and get that fool out of there. We had a 120 main jet in there we're going to put a 115there at sea level which would probably be perfect but we're about a mile above sea level in denver colorado so we need less fuel to be able to put the carburetor back on because next we're just going to be dealing with the needle that's off the top we don't need to have the carb off let me crank the sink down if we wanted we could try this at this point but like I said I do this all the time so I know what I'm doing in general you don't want to do two things at once just one thing at a time so you don't get confused so I'll just open the top here so we can get to that needle once we get to that needle we're going to tilt it out just a hair removing the clip and moving it up into a slot that will lower the needle so pull that out I don't think I've shown you how to do this so you're going to pull this out like this basically you're pulling of the spring back and then you can pull the cable out.
You notice there's a little padlock there. where it locks in place so here's our needle here's our little diagram right now our needle is set into clip number three and we want the needle to go down to cover up the main jet hole a little bit more so we're going to put that clip at the number two mark ok i got it all set slide it down into place this is a bit of trial and error if we went too far or not but the good thing is we have that broadband and we can do that take the guesswork of what our actual tune is bet you were right money guaranteed so in an idle state we're doing pretty good like 12 afr on a cruise we're like 13. 13.7 12.5 that's perfect so i think you guys figured it out the picture jet pilot adjust idle air fuel mixture screw adjust idle mixture once you get to cruising speed quarter throttle three quarters of throttle e acceleration which will be your needle jet and high rpm is the main jet all four circuits are easily adjustable and if you do the wide band and have a little bit then it makes life really very easy.
Now let me show you how to tune an efi system. A fuel injection system. It's much easier. carburetor rotary wrench manual tuner we have this one there are many different companies on the market but this is all you do it's super super easy so by the way this is our 232 this is a monster right now it's idling at 2200rpm but check this out for whatever you do for a fuel injection don't get your hands dirty or anything this would be like the pilot jet so I'm tweaking this all I do is hit enter it's tweaked I've enriched it The fuel system fuel injection is much easier than a carburetor.
Throttle response on fuel injection is unreal. I just wanted to show you the difference. They wonder why the engine sounds so loud. I know I'm going to get a lot of comments about it. that's a dry clutch so that's your noise' I don't hear any problems with the engine. That's how it's supposed to sound. That was an extremely long video with a lot of information. you like the video press the thumbs up button if you didn't like the video press the thumbs down button twice I appreciate you guys and see you in the next video

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