The Best Two Stroke Jetting Video You'll Ever See!

The Best Two Stroke Jetting Video You'll Ever See!

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Alright. Guys I'm gonna be covering the art of jet eot stroke today now, this is gonna be a long super, detailed video so you may want to sit down crack, your cold one and enjoy, this video alright. Let's get started. So. Let's start at the simplest of levels, what exactly is Jenny so, jetting, is changing. Out these little cylinder shaped pieces that, have a whole throat just a tiny microscopic, hole. Inside. The carburetor here, to. Allow for more or less fuel to enter the engine when you install a smaller jet that lets less fuel into the engine causing, a leaner mixture, and on, the other side a bigger jet creates a richer mixture so, that's like the bare basics, of jetting, and so, what we're trying to achieve here is the optimal, air to fuel ratio and, for, most engines that's gonna be 14 point 6 to 1 so, that's one gram of fuel and fourteen. Point six grams, of air to, combine to make the perfect ratio now. That number doesn't really matter and we're not going to use it for jetting and all more. For just information, purposes so. What happens when an engine isn't jetted correctly if it's too rich mean too much fuel it'll, bog out like you whack the throttle and it'll, cop out and then, it won't rub out all the way and then, it'll cough and sputter throughout the upper rpm range, too and if, it's too lean it'll. Have a hanging idle meaning you rev it up and it takes forever to idle back down. Lacks. Power you, may hear like a knocking, noise to it it. Feels like super zingy it's, kind of hard to describe that term and then. It'll run super hot too if it's really lean and that's, what leads to an engine seizure so. Obviously both of these are kind of dangerous, conditions. Of being especially. Being lean that's what will destroy, your top-end your crank and then. If you're too rich you. Could cough. Out or bog out when you're riding especially, kind of face of a jump or. You. Know whoop section or whatever it might be and, that, obviously would not be a good thing to happen alright, now that you kind of understand what jetting is all about let's, talk about a few things before we actually start getting so. Say your bikes run like ass and you want to dive just right in the jetting and figure this thing out but. There's a couple simple things you need to check / before, you actually start pulling the carburetor apart and switching. Out Jets so, first thing popping, a new spark plug, make sure your filter is clean those. Two things will, make a big difference when it comes to jetting you have a plugged air filter that, will just throw everything for a loop you know same thing with a a worn. Or really valid, out spark plug. Make. Sure you have good compression, may. Want to test the compression, before. You actually start jetting, to diagnose any issues. With that and then obviously make, sure you have a clean carburetor there's no plug jets or plugged up vent hoses that'll really mess things up too. If. You just rebuilt your bike make sure you break it in that. Actually changes quite a bit once, you have it broken in they'll create more compression, and change. How much fuel the engine requires oh and, another big thing is float height if you don't have the correct flow height that'll, actually change how much fuel is available in that float Bowl for, the Jets that stuck out of so. If that's off that'll, make the whole jetting process kind of a nightmare and one more thing you want to make sure your bike is warmed, up completely, before you go out and test it just even swear I'm properly a cold, bike runs way different than a warm bike does alright, enough talking I'm gonna pull the carburetor off of this bike take it apart completely show. You the ins and outs of the carburetor all the circuits what, effects how it runs down low the mid-range and then, when you've got it pegged up top so just kind of cover all the basics, before, we actually start with the jetting process oh and, one more thing most bikes you can get to the carburetor or jet, the carburetor if it's still on the bike you, can do it with this one you just got twist the carburetor in there but. For this time I'm just gonna pull it completely off show. You guys the ins and outs like I was talking about earlier and then, we can start swapping out jets and all that I'm, gonna see how fast I can pull the carburetor off of this bike I'm hoping I can do it in under two minutes start. The timer right now. So. There's four components, here to the carburetor that we're going to check out that effective, jetting and how the bike runs at a certain rpm the. First thing we're gonna look at is the air screw, on the backside of the carburetor don't. Mistake it for the idle screw which is usually on a throttle, slide and towards. The center of the carburetor and then.

Number Two we've got the. Needle on the throttle, slide and. Then, inside, the float Bowl we've got the main jet in the pilot jet so, the football is what contains the fuel and that's, what the Jets draw feel from and ultimately. What provides fuel to the engine all right I'm gonna pull the float Bowl off and show you guys the main jet the pilot jet and the, floats as well. So. Here we've got the main jet the pilot jet down here and the. Floats and then, hanging on this little tab here on the floats is the. Float needle and that's, what controls the fuel flow into, the float Bowl earlier, in the video I was talking about float height and how important it is to have the correct float height so, the float height ultimately, determines, how much fuel is available in the float Bowl for the Jets to access and if, you don't have enough fuel in there the bikes gonna be starving for a few obviously, and if there's too much fuel in the float Bowl the bikes to me bogging out stumbling, and just not running too well so to check your float height we're gonna let the floats extend, all the way and then. Tilt the carburetor back and let them settle so. Right there they're settled but they're not pushing in the float valve so. Right there would be pushing in the float valve you want it sitting just right up on top and then, you measure from the top of the float here to. The float Bowl gasket. Surface and. Every, bike is gonna be different so check your manual to see what the correct specification. Is and to adjust the float height you just bend this little tab that the float valve is hanging from so. When you bend it down that, increases, the float height and bending. It up goes the opposite way so definitely, before you do any jetting make sure you have the correct float height in your carburetor there's, a number of components here that affects how the bike runs throughout the RPM range so, we're going to start at the very bottom so, from idle to quarter throttle is the, pilot jet this, one right here and, the. Air screw so. The air screw is what, controls, how much air is being, delivered to the pilot jet and this. Screw is how you tune in the pilot jet as well so, with the air screw the, farther you go in the, less air is going to the pilot jet which. Creates, a richer, mixture and then turning, that screw out, brings. More air in and creates. A leaner mixture, I'm going to talk about the air screw and the pilot jet later on in the video but. Basically how you tune in the pilot jet with the air screw is when. You're at a certain amount of turns out with, the screw that'll. Determine whether. You should go up or down on the size of the pilot jet and then next up what controls, from quarter throttle to 3/4, throttle is the needle here, on the throttle slide so, you can adjust it up or down and that. Changes, how much fuel is being delivered throughout, that throttle range and there's actually two more pieces here that factor, in the jetting as well but, they're not that applicable to most situations so, I'm not really going to touch on it a whole lot so. You can swap out your throttle slide for something different with, a different cutaway or a different shape and that'll. Affect how, much air is being let into the engine which obviously affects jetting, and you, can swap out your needle for something different to one, last longer or shorter or a different. Taper here on the end but, you're gonna notice the biggest difference, in adjusting. Your existing, needle up or down so the throttle slide just slides right into the carburetor right here and. When. You twist the throttle the slide goes up and down and allows, the air and feel mixture into the engine so, that needle, goes down into the float Bowl and through. The main jet so, when you twist the throttle that, needle allows fuel, from the main jet to enter the engine and move the needle up or down you just reposition, the clip on the needle in a different position there's, usually like five or six different slots, on the needle so, when you move that clip down that. Raises, the needle and creates, a richer mixture and then. When you raise that clip that, lowers the needle and creates. A leaner mixture, and then last up we've got the main jet this, jet makes the biggest difference of all your jetting changes and it's gonna be the most common jet you've got to swap out so, this one controls from half throttle to, wide-open throttle to recap we've got the air screw and this is what you use the tune in the pilot jet so. The pilot jet and the air screw control. From idle to quarter, throttle and then. We've got the needle which controls, from, quarter, throttle to 3/4, throttle, and. Last up is the main jet and this, affects, from half throttle to wide-open throttle so. I'm gonna get this carburetor back together put, it on the bike and then, we can start the tuning process. One. Last thing to discuss before we dive into jetting and that is what affects jetting, and what.

Kind Of things require, you to reject, and, that would be weather so. Like humidity, temperature. And then. Elevation, is a big one too, modification. So if you did like intake, or exhaust modifications. Of your bike that. Would require you to read jet and then. Maintenance. Things too like if you're lowering compression, where you got a dirty air filter or, other. Things just aren't up to par that. Will affect jetting too and how temperature affects your jetting is when, the air is warmer it's less dense and so, you'll need to go down on your jet to compensate, so. Less air available, means, the requirement, for less fuel and that when you go up in elevation the, air is thinner so, same concepts temperature, less, air available requires, you to go down on your jet so, for modifications, generally, that requires you to go bigger on your jet so, if you have a more free-flowing intake or exhaust that. Is more air traveling, through and that, requires, you, would have more fuel as well one, thing that's super important, with jetting and will save you a lot of frustration is. Just going step by step and only make it one change at a time say. If you change our needle position and your main jet to the same time and it, negatively impacts how your bike runs you're, not going to know which one affected. That so, just keep it simple, so the first thing we're gonna tune in here is the air screw and the pilot jet now, the pilot jet is gonna be the one adjustment you're gonna touch the least once, you set it you're pretty much good to go with that and for, the air screw when you change elevation, or the temperature or humidity changes, that, is gonna be a screw you're going to adjust so how do you know if you have to lean or to rich of a pilot if it's to lean the, idle will surge meaning, you'll go up and down up and down and then. When you crack throw all really quickly it'll cut out or bog and then. It'll have trouble, I linked down as well so, you rev it up and it takes forever to idle back down and then. When you have a rich pilot jet, it'll, sputter when you open the throttle it'll follow up plugs and it'll. Be really hard to start as well so, how I'm gonna tune in the air screw and the pilot jet is by going three turns out on the air screw and then, work my way back in half, a turn at a time until, the engine starts to stumble and the idle isn't very smooth then. I'm gonna go back out half. A turn at a time until. That idle smooths out and the throttle response is, crisp and wherever. I end up with, the. Air screw as far as turns out that. Will determine whether I need to go down or up on the pilot jet and there's a few other methods out there for tuning in the air screw such, as adjusting. The screw until the, engine reaches, its highest rpm but. I've always found that going by the sound of the bike the throttle response and, the idle that's, always worked best for me now, I'm going to fire up the bike let it warm up and then turn out this air screw the three turns out and then, work my way in from there. One. One. Half. To. Two. And a half and. Three. So. The bike died when I turned, that screw all the way in but. Now I'm at three turns out I'm just gonna start it back up and. Play, with that screw some more. So. You could hear right there the thaw response, is pretty crisp but, I'm gonna start turning in the screw until. It starts to bog out or starts to stumble when I turn the throttle and so as you're turning in that air screw and you get to a really rich position, it'll, sound like the choke is on so we'll have like a sputtering, or, like a really choked up sound to it. And. As. You heard right there it bogs out pretty good and the. Idle just goes down really quick so definitely too rich of a position so, I'm just gonna work my way out a half, a turn out of time until. It cleans up and then I'll count how many turns out I am on that screw. So. Right there seem to be the sweet spot, I turned, the screw out until, if our response cleaned, up and the Idol smoothed out as well and now, I'm going to show you guys what a lean condition will sound like I'm, just gonna continue turning that screw out and we'll see what happens.

And. So right there I'm about three and a half turns out and as, you heard it, takes a while for the Idol to go back down to normal and the, throttle response is, like super zingy just, has like a light feeling to it the. Best way I could describe zingy, is it. Just has like a different, sound. Of the like the ding-ding-ding, to it and, once. You play around jetting enough and messing, with the air screw you'll, be able to identify the difference between a normal tone. Of Idol and a, lean tone of Idol and actually, I forgot to check how many turns out I was earlier when I got it running crisp so I'm gonna take you through what it should sound like again I'm, gonna start with the screw all the way in this time and back. It out until, I get it run really good again. So. Right there is a sweet, spot again, good, throw response, and the Idol is pretty smooth see. How many turns out I ended up at so. That is gonna be a half. One. One. And a half. Two. And. So. Two and a quarter, so. I'm gonna set it back to two and a quarter a quarter. One. Right. There so. That's, two and a quarter. Ideally. You should have your airscrew between one and two, and a half turns out if, you reach the best running condition under turnout. That. Indicates, that your pilot jet is too, lean so, you have your screws so far in that you're barely letting any air in to make that good ratio and then. On the other side of things if, you have the screw more, than two and a half turns out to get the best running condition that. Means your pilot, jet is too rich so. You're letting a ton of air in to. Make that good ratio once, again so. To recap if you're less than one turn in maybe. Bump your pilot up one, size and then, if you're more than two and a half turns out bump. Your pilot, down a size. So. The only times you really need to mess with the air screw is if you have a really warm or really cold day where, you go up or down in elevation or, you, add a modification, to your bike so. Say if there's a really warm day you want. To lean out the bike a little bit so maybe go a turn, out or half a turn out I should say see. How it runs and then, if you go up in elevation you'll, need to lean it out there too so, once again try, going half a turn out see, how it responds and, go, from there and then if you add a, modification. Such as a silencer, or a pipe you want, to rich ended up most of the time I mean usually the, manufacturer.

The Piper silencer, will they'll. Tell you what you need to do there but. You. May want to go you know half a Turner or turn in and see how the bike runs with that so say you adjusted, your air screw and you came to the conclusion, that you're gonna need to swap out a pilot jet I'll show you how you can go about that without. Removing, the carburetor from the bike so, first you're gonna have to turn, the fuel off and then. Loosen, up the clamps, on, both sides, the. Carburetor now. With. The clamps loose you can pivot it that way you can get access to the, nut on, the, bottom of the flow bowl here. And. On this bike it's a little easier to remove the front sprocket cover just, gives us a little more access to that, football nut. So. This is a 17. Millimeter and as soon as I loosen this nut up there. Is gonna be some fuel that's gonna come out so have, something. On hand to catch it or like a rag to soak it up. So. To give you guys a little better perspective on how to get access to that pilot jet we're gonna lay the bike on its side the, jet you see right here is the main jet super, easy to get access to but. The pilot, is up, here in the front tucked, way up in there and, you have to fish around with a small flat blade screwdriver to get to it so, you want to push up on the carburetor, to get as straight of a shot with the screwdriver as possible. You. Neither tilt the bike back up and the pilot jet will fall out or use, a set of tweezers or, needlenose. Pliers to, get that pilot jet out of there. And. To get the pilot jet back in there just feed it in with, a set of pliers or tweezers. Kind. Of push it up with a screwdriver. Right. Into, the hole there, you. Want to get a straight, shot with that screwdriver that way you're not cross threading those threads either. And. It's pretty easy to get a false tighten here on the pilot jet if you have the screwdriver cocked at an angle when you're tightening it it'll. Feel like the pilot jets tight but it actually isn't and then, you go to ride it and it falls out that's actually happened to me before, and it, feels like the world's crashing down like the bike just bogs out terribly, and you. Wonder what the heck is going on you, can just put the football cap back on, tighten. It up give. It the carburetor, back into, place. Definitely. Want to make sure you tighten up your air boots clamps as well and then. You can go test out that jet see how it responds. All. Right so I've got the pilot jet and the Earth's crew all tuned in and next, up for tuning is the. Kneel position, here in the throttle so, remember this is the part that controls from quarter, to 3/4, throttle so. To get to that needle I'll have to pull the cap here off the carburetor, and. So if you have a carburetor that has a screw, on cap you know does a twist on cap. It's, pretty easy to get to it with the carburetor still on the bike but. With this carburetor there's three screws holding. The cap on and I've, always found it easiest to just pull the whole subframe, off like I had earlier on, this bike it's also easier, to remove the top shock bolt that, way can pivot Chuck out of the way and get, access to the carburetor it's only one extra bolt and it makes. Life a lot easier. You. Just got to lift up on the back wheel kind, of get some free. Play there and then, just slide out the bolt and the shock will slide, out of the frame. Slide. The carburetor out of the, intake manifold, my.

Way Can get to these throttle, cap. Screws here. And. Then once all those screws are out the, throttle slide this comes out of the carburetor. You. Got to be really careful with that needle not to bend it too, so. This is the needle I'm talking about adjusting, and. With this carburetor just pull the spring the, tension off the spring, pinch. The cable with your fingers like that, push, it down inside, the throttle slide and it. Pops out and now, we need to get access to the clips here on the needle so, to get the needle out of the slide there's, a bolt that holds the, needle into place. So. Right now I've got the clip in the middle position on the needle and the bike seems be running super good with it in that spot but. I'm gonna show you guys what, it would sound like or how it would run with this, needle rich and all the way up so. I'll remove the clip to the bottom, position here, so, that's gonna raise the needle and rich, in the condition, and so I'm going to put the bike back together and see, how it runs. So. That is the very bottom position, here on the needle and if, our days that clip to the top position that. Would drop the needle within the slide and lean. Out the condition. So, just like when I pulled it apart gonna, have to compress the spring, grab. The cable kind of pinch it with my fingers. I've. Got a good amount, of cable poking, out there. And. I'm just gonna slide, it into. The. Throttle slide and you'll. Be able to feel it hook and, then. You can release it, sometimes. This is a bit tricky to do when the cable. Is still on the bike. So. I've got the cable hooked inside, the slide it's, gonna release the spring. Make. Sure the. Cable, is actually, hooked to the slide and then. This goes right back in the carburetor. If. You guys are enjoying the videos and are learning a lot I would really appreciate it, if you support the channel by shopping over at Prime MX com I've, got some hats t-shirts. Stickers. And, a, few of the supplies I use throughout the videos over there as well and another, way you could support the channel is by, using the Amazon and eBay affiliate, links at the bottom of the, description so. How this works is whenever, you make a purchase through amazon or ebay through, those links i get. A small commission and it, doesn't cost you anything extra so. Just a simple way of supporting. The channel and what i do and so what you could do is set those links as a bookmark. On your desktop, or your mobile phone and whatever. You want to make a purchase on amazon or ebay you just click through that link it'll be right there and, it makes it really simple so, i'd really appreciate it guys thank. You finding, the correct needle position can be pretty tricky and it's, a lot easier to identify a, rich condition rather, than a lean condition so. What I would do like I did here is start. In a really rich condition and work, your way leaner until, it clears up so. A rich conditions gonna sound like the choke is on it'll be sputtering, and it. Won't accelerate as quickly, as it should and so, how you test the needle position is by warm up the bike and going, through the gears only, accelerate, until about half throttle and, if, it starts to sputter out or cut out that. Means the condition is too rich and you're gonna have to bump that clip up a notch so. Try to just go one notch at a time or like with the Jets just, go one size at a time so. I'm gonna take this thing out and see how, it runs with that clip in the, richest position. So. Like I was saying it's, gonna bring the bike up to about half throw all throughout the gears and see, if it sputters out or cops, out at all any signs, of a rich condition. Give. That another shot here. You. Can hear right in the mid-range there, it's kind. Of cutting out, which. Is right where that needle, would be affecting, it. I'm. Just gonna make one more run down. Here and see if I can hear it a little more a little more clearly. Right. There I'll. Go back in the first gear. Yeah. Right there at super-rich and, that's. Where. The deal will be affecting, in the right, in the mid-range. So. I'm going to pull this thing back apart and move. That clip position, now. I'm going to put that clip back into the middle position since. It ran really good within that spot before. So. I'm gonna let the agent warm up and then I'm gonna take it down to drive it once again let me go until about a half throttle, and, I'll. Show you the difference between a, needle, position that's way too rich and one, that's just right so like you heard before about half throttle it was super. Sputtering, and, it just did run very smooth and all that should be cleaned up now. Sounds. A little better I think, it needs to be cleared out just a little bit more. Definitely. A lot of smoother running. Yeah. That is a lot better. Keep. In mind a keystroke has never gotta run perfectly, food just. Together so, she like what 25 like this isn't really meant to be run.

In The mid-range you know all day you're supposed to be more. Wide open with it so, it's. Never gonna run just super, smooth like a four-stroke, does, so. You guys heard how the engine runs with that needle in the richest position, but, if it's on the leaner side of things the, engine will sound kind of quiet and have like a dead feeling to it and when, you give it full throttle, they'll hesitate, to so. You always want to be on the richer, side of things with, the needle since it's kind of hard to identify it whether, you're rich or lean with. That without, adjustment, there so. Like I explained earlier you, want to start with, the, needle and a richer position, and then work your way leaner until it cleans up like I did here and now for the main jet I'm gonna do something pretty similar to what I did with the needle adjustment, gonna, start out really rich to the point where it's sputtering, or it feels like the choke is on at high rpm, and, I'm gonna lean it out until all that clears up so, once again you always want to be on the richer side of things just to be safe so right now the bike runs really good with the main jet where it's at but, I'm gonna bump it up a few sizes and show you how it run in a really rich condition and then, go through how it tuned in the main jet from there just. Like any other jetting change you want to make sure you've got the bike warmed up before you go and test it out so. For the main jet it affects from half to full throttle so. I'm just gonna go wide open and see, how that fat our main jet affects it I'm guessing, it's gonna sputter at full rpm because, that jet was a size. R - bigger than what I had there previously. Still. Need to be cleared out a little bit there's, a little bit of clutter, there though. Yeah. You can definitely hear a little. Bit of spider, at the very top there where. It's like cuts out it's not completely smooth we're. It's not clearing out 100%, of the way. So, 1/8 overly. Rich it seems like but. Definitely on the richer side of things. I'm, gonna pop in the old debt I believe. It was the 410, and. I'll show you the difference that makes at the full full. Throttle, there, after. Running the bike for just a couple minutes with that bigger main jet we've got quite a bit of spooge coming out the silencer, here definitely. A bit rich so, swapping, out the main jet is going to be very similar to the, pilot jet got, the bike leaned over on a stand just going to loosen up the carburetor tilt it off to the side remove. That, nut on the bottom of the float Bowl here and then. I'll be able to get access to the main jet. Alright, one last little cashier should, be running pretty crisp now. Sounds. Pretty good still a little bit of sputter up. On top. But. It sounds better than it did before give it another couple runs down the driveway. Better. Sounds. Really really, clean now. Yeah. It's perfect. Just. Where I wanted to see it at yeah. It sounds good. Yeah. I'm gonna call that good right there, if. I really wanted to see exactly where I'm at for. For. Jetting yeah rich I am I could do a chop test in the spark plug and that. Would tell me everything I need to know so. If you want to see how a chop, test is done on a spark plug, just. Find, the jetting or the spark plug video over. On my channel. To. Recap with a main jet you want to start out really rich and then work your way leaner until it cleans out on top and then just leave it up right there and it's always a great idea to do a spark plug chop test to see exactly where you're at with that main jet so that pretty much wraps up the ins and outs of jetting a two-stroke, carburetor, as, you can tell if there's a lot of going by the sound and feel the bike and as, you do it more and more you'll get a really good gauge whether you're too rich to. Lean or just, perfect, with your setting so, it takes a lot of patience, at first and you only want to make one change at a time so if you're messing with your pilot jet don't make a main jet change or a needle, position, change at the same time and don't, make your changes too drastic, either try, to just keep it one size or like a quarter, or half a turn that time and you'll. Really be able to dial it in another, good resource for jetting specs is, gonna be Google or like a pipe or carburetor, manufacture safety. Put an F F pipe and silencer, on your bike go. Check out their website or like, pro-circuit or build wherever it might be they're. Gonna have some, recommended jegging specs on the website for you to start with and then, you can just kind of find - from there and if, you did more extensive mods like say carburetor, a big board or a stroker, crank do.

A Google search and, forums. Like vital, MX thumper, talk or a, few others will pop up and, they'll. Have a good baseline spec for you to start with and then, you can just kind of work from there - so the only difference between getting a two stroke and a four stroke is the air or the fuel screw on a, two stroke it's called an air screw because it controls how much air is being let into the pilot jet circuit and then, on the four-stroke it. Controls, how much fuel is being let into the pilot jet circuit as well so. On a two-stroke when you turn that screw in it, lets. Air into, the circuit creating, a richer, mixture and then, on a four-stroke, it's the opposite so. You turn that screw in and it lets less. Fuel into, the circuit, creating, a leaner, mixture, one thing I would recommend doing is check in the color your spark plug throughout the jetting process, and afterwards, as well so. I have a couple fresh plugs on hand pop them in and keep, an eye on them throughout so. I actually did a video a really detailed video on how, to check the color your plugs and there's, also a lot, more you can read from a spark plug as well and you, can watch that video by clicking a circle right up here in the corner, now. If you think Jegs a bunch of BS and you want a way around it these electronic carbs are a really good way to go so, basically how they work is they've, got a metering, rod inside of it which is able to automatically, determine how, much fuel the engine needs based, on airflow volume and temperature, so. Pretty much eliminates, any need for jetting, changes so, this is the car blow up using on my cr250 build and I'll have a ton of videos coming out on the ins and outs of it how, to set it up how it runs and my overall impression, of it so, lots of exciting content. Coming up soon now, before I go I need to pick the winners of the works connection sticker packs from the last video so, let's head over to the random color picker page and find, out who the winners are so this is what I'm going to use to pick the winners here it is a random, comment generator so. I've got the URL punched, in I'm gonna load up all the comments here. Should. Be quite a few in there. Probably. Over a thousand, I'm guessing oh. Yeah. 12:27. Come. Down here, hit, the start button, and. That's, gonna pick a just, random comment from that video. So. The only requirement. Was you had a comment WC. So. First, winner is motoboys. He. Commented, WC, pick. Another one. Yeah. Didn't say WC. You, are wrong reference, your service manual for the proper spark. Plugs readings, sorry.

Buddy, Gonna, pick another winner. All. Right Stephen, Holsinger. Says WC. So. That's winner number two. And. Then. Aidan, Zollner, says, would. Love to see a jetting video doing, that right now. WC. So, that's winner number three got two more. So. Keep in mind if you see your name pop up here you. Got to send me a message here. On youtube with, your mailing address all. Right little dude isn't winner number four. And. The. Last one is JW. Films so. All, of you guys who, won the stickers send, me a message here, on youtube you. Just got to go over to the about page on, my channel. Hit. The Sun mess send, message button and, shoot. Me your mailing address and I get those thicker packs mailed out, all. Right that is gonna wrap up the video really, hope you guys enjoyed it and learned a thing or two this, video took a ton of time and effort to create it so I'd really appreciate it if you go hit that like button and, subscribe. To the channel as well thanks. For watching and keep it Prime. You.

2018-07-11 09:01

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Japan, Africa, U.S. STIC around the world is the one to beat. Endorsement from Africa; Mark du Plessis To George Boswell Today at 1:12 PM: Hi George. STIC test: “….Yes I have done some testing, but only managed to test rides before i broke my hand, so, i have had to wait for this to heal. Results were very good already on KTM 300 XC 2018. It is far superior to Smartcarb, modified mikuni and straight Keihin. So i am definitely a believer. I haven’t had a chance to test the small bores yet, where i am hoping the proposition is even more compelling. I am very impressed with the part throttle response and believe there is more to be had with some experimentation. I want to try your advice to use far larger pilot jets….”

I love your videoes

Great video Cameron! Super informative for all knowledge levels.

One time my pitbike was sputtering and coffing and I take the bowl off my main jet was in the bowl lol

Hey man not sure if it's just my phone or the video but the video was choppy & sputtering the whole way through! First time I ever had this on one of your vids, just figured I'd let you know. Great videos man! Keep em coming, love them.

When replacing things like the pilot jet or any Bolt, Sensor,Screw that is hard to line up or get to. Use a piece of plastic or rubber tube to hold the item so it's like a flexible drive, once you have it started then up can pull off the tube and then use the correct driver, If you cross it up the tube will slip and not damage the threads.

Why does my rm85 keep eating and insane amount of gas, i always have to fill it up often

I live at about 1000feet elevation and I'm taking a trip to about 4000feet (Moab) I have a 2014 ktm 250 xc should I be worried about the jetting? Will it mess up my bike. I'll be riding every day for about a week. Thanks!

Can you make a video on how to lower your suspension

You need to just give up on that 125 and get yourself a 250f

Wow!!! This vid gives me the confidence to make my first comprehensive carb adjustment. Thank you very much!

So when the bike is lean it will pop pop pop when it’s revving down

love your work

Well explained in layman’s terms, have you checked out G9 rm vids. Thanks Cameron.

I'm glad I watched this. This is very informative

What was that tool that you used to get the main jet out?

Super clean image man what video camera are you using super clean love the image and great video excellent job

Thanks man I'm using a Canon 80D

its ok to be a little rich. infact most of them are factory slightly rich because well being a little bit rich wont hurt a thing. being a little lean will cause premature wear but better performance. like cam said BREAK IN a new top end/ bottom end. one or two tanks. someppl say break in for one tank i say taker slow, check ur elevation and pressure and temps, those all change jetting. few things to keep in mind not covered here love the vids man, you work harder then i do on my bikes.

Hey Cameron where do you buy jets? I assume u buy like 32pc kits at a time?

Thanks for this video. its great reference material. should be a mandatory view in mechanic school. keep up the good work. Your subs/views will continue to accumulate over time. Your vids are time proof.

Hi Cameron, how should I clean the inside of my 2 stroke exhuast? I don't want to burn it out becuase my pipe is chromed and I would discolor it

TheNoobStevio ok

Karrie Bhurgari probably dry degreaser and wire brush to start

Great vid

Hi cameron, my old 92 cr125 was running fine when breaking in the new piston then it started to run rich and foul plugs any ideas on what this could be cos i dont?

hey, do you know how to make a racing atv like honda 400ex quieter? Annoying people are complaining because its to loud when we ride on our own land...

Change muffler to softer one

Thank you so much for this video bro, #1 YouTube guy!

Super complete guide! Thanks Cameron! #Pryme

This video is definitely going to be my go-to next time I need to do some jetting!!! Also, the beard is looking good :) Keep up the good work

Love the videos. I've learned so much! Can't wait to see when you crack open your friends engine to replace that crank bearing

Wow thats a very good video. As usual :) now I get my KTM run perfectly thx.

thank you Cameron Niemela for making this video I along with others learned something helpful and positive today

You should do a 4 stroke jetting and carburetor vid soon but mad 2 stroke vid

Now what would i do differently if its a keihin with a main, pilot and power jet? Its super rich from 1/4 turn until about 3/4. Ive changed the main from a 175 to a 165, the pilot from a 50 to a 45 then a 42, power jet is stock at 50. And my slide needle from the 3rd clip to the 2nd. It runs great from about 5/8, 3/4 to wide open and sounds crisp but is awful rich from 1/4 til i hit the powerband? All i did was put a pipe on and a set of vforce 3 reeds in it.

Oh and my air/fuel screw is at 3 turns out and still runs super rich in that 1/4 to 3/4 throttle range.

Great job, as usual!

Great job

The CN should be Cameron Network... well done.

Yesss, Lectron! I told you!

Did you literally put a Lectron on and never touch one this video except with your dickbeaters?

It’s taking way to long to complete it

When is the 250 going to be done

How much of this information is the same for 4 strokes? I am just curious because I do not understand the jetting on my Honda but do know that it is definitely running rich. Great video!

Thanks for watching! All of it is applicable to 4 strokes besides the air/fuel screw

Very helpful and informational thank you!

awesome video, I could see this being the #1 video on you tube for jetting in no time. Now do you dare to tackle the battle of fuel mixture and what that does to the bike?

Ok so my bike was running rich for a while and I tuned it pretty good. There is still a bit of spooge coming out of my exhaust though. Could that just be my bike cleaning out all the excess spooge?

Most of your videos are the best videos I've seen on their respective topics my nigga

Most educational video I've ever watched!

Wow what a good video will help a lot of people !

Great vid. Finally got my cr85r runing right. This vid looked like a lot of work. Definitely the best jetting vid i've seen.

Great vid finally tuned my bike right

so helpful

I got the same carb on my rm125

I have been having problems setting up my 03 cr250, this video combined with the video about reading the spark plug is perfect. Thankyou...

Great description of jetting

Great Video!! thankss

Make a video about power valve problems and tips

what can be wrong, if my bike stutters on high revs?


Thank you so much for the video bro !!

Whats your favourite brand, mine is Honda for sure!

bana 2strong 80cc bir kalbiratör lazım

Gotta agree, hands down the most detailed and longest jetting video to be seen yet


keep it up man

Keep up the good work love the video's

love it

The effort you put into these videos is second to none, really love your work cam. Keep doing your thing man you're very much appreciated

Great job. Excellent detail and in depth explanation.

Race team certified for sure. You tore that bike apart pretty fast. Great detailed video, learned a lot. If I only paid that much attention in school hahaha

Lovely bruh. Thank for video.

Can you do a video on carburettor tuning for a four stroke 450?

Great video but I must correct you, the 14.6 (or 14.7) is the ideal stoichiometric ratio (at which all of the fuel is burned and no oxygen is left unburned) but thats far from what you are trying to acheive on a bike and is "optimal" only for a certain power range, at idle and low load you are at lean up to 17 (sometimes 18) :1 and on high load at 12.5 (or as low as 11:1 on high output engines) to cool the engine.

Great content this will help me out a lot to sort out my jetting out thanks for tacking the time to make this vid.

Awesome video! Just what I needed

This is such a perfect video. Straight to the topic, no useless BS, everything nicely explained and easily understandable. No problem with adjusting those 2 smoke jets now. Thumbs up and new subscriber here!

nothing llike a 2 stroke in the powerband,nice

Excellent video, so helpful and easy to understand, thanks for going to the trouble to do this!

Absolute legend. Definitely coming back to this one when I finally tune my bike!

Great video, can you do a short video for 4 stroke bog and lean conditions . Thanks

Hi Cameron, really like your video,s i have a question i have a 1999 RM250 and it bogs a bit and it shut off while running in neutral i don’t know so much about the carburetor there are a lot bolts on it and i don’t know what is what so can you help me with fixing the issue i can make a video for you to explain my full problem i hope for a reaction already thanks!!

Super job.

One of your best vids nice work. I’ll be sending this to a whole bunch of friends that need to learn how to work on their own damn carbs. This is perfect.

Man, you make a great job. Thank you very much. Greetings from Barcelona.

Great vid but is it just me that i hear something moving in the engine while the revs go down?

That's a normal sound with these bikes

My bike bogs and it also has a hanging idel, what do I do?

David Bramhall you probably are running rich and have a vacuum leak also

Bonjour Cameron ! Excellente vidéo

Love the long videos

This guy's always on time lol, everytime I have an issue and can't figure it out Cameron always the next day posts a video about it. Done this 4 times so far... I have jetting issues been looking and now this is posted lol.

same exact thing happened to me twice! Cam’s a lifesaver fr!

Great video on tunning carbs, you have the best how to videos ,I was so over jetting and went with a Letron Carb on my CR 250, one of the best things I ever bought for my bike, so simple to tune! Bike runs perect all the time... hot and cold weather Hi-low elevations! The Best Carb on the market hands down!

Its an 07 CR -The guys at Lectron are way cool, they will tune your carb real close to the specs required for your bike and answer all your questions in detail, Go to their website and go to offroad, click on Cr250 and get the Metering rod adjustment tool kit for the extra $17, I couldnt get enough play on my throttle with the metering rod cap it came with, couldnt get my bike to idle correctly so they sent me a low profile cap that worked out perfect, the carb is so easy to tune, turn the metering rod to the left to lean it out and right to richen, I did mine a 1/4 turn at a time and just looked at my spark plug to get it perfectly where i wanted it,.there are plenty of how to videos from lectron on tuning. I think this carb should come factory on all bikes!

shawn rich what year CR? I went with an Airstriker on my 98. The powerjet carb that came with it was a nightmare, it's a totally different bike now

Nice vid dam I didn’t win never do

Great videos,,thank you!

This works on a 50cc also?

kalle korpela every carb, things might be in different places etc but the theory is the same

When’s the winner bein picked for stickers and when is the next cr 250 build .. I know how little things can hold back a build hahah respect cam your the best at what you do

What do you think about jetting it by the motorcycle owners manual? I have husaberg te 250 2014 and i jet it owners manula and it runs sweet

Luka Ožbolt they always go a bit rich in the owners manual, if you're looking to get maximum power try leaning it out just a little further

Awesome video Cameron!! I learned a lot from watching this. Always been a little nervous about messing with the jets and screws.

Thank you so much I defiantly need to richen my 85 up!

Where are the Amazon links when using mobile phone? I dont have a desktop.

Cameron Niemela i see them now, just gotta tap the arrow to open the description. It doesn't automatically show the description on mobile.

They are at the bottom of the description.

Just bought a 1988 Cr250r last week. That thing can rip! Don't have any jetting issues, but I just like watching the vids and learning more.

Great video dude! Very detailed. I had the 07 cr250r was a great bike but stock head squish was out from factory and was a bitch to jet until I got a VHM head for it which corrected squish and made it run so much better on pump gas. I have a 2015 ktm 250sx now and from factory it was bog rich on the pilot and needle clip but safe for run in, After run in i dropped 1 size on pilot, dropped 1 needle clip went up 1 size on main jet and now its jetted to perfection and has no bog or sputter and doesn't eat plugs. Pulls my arms off now haha

Was having issues at the present time. This video is just what I needed. Thanks

It took me years of self learning via books and youtube to figure out what you just explained in under an hour. Clear and concise. This should be a mandatory watch for anyone new to tuning carbs. Great job!

Cameron, love the videos. Thanks a ton for all the great info. I’ll be ordering pats through your link in the future for sure. I’ve got a 2006 RM250 modified for single track trails: FMF Gnarly & TC2, 10oz flywheel weight, Moose reed spacer... I live at 6000’, I ride from 4-10,000’, mostly 7-9000’ in summer when it’s hot and dry. I bought the bike used locally, stock pipe and silencer. Stock jetting is 50 Pilot, 172 Main. When I bought it it had 48 pilot, 168 main. Needle clip was in the middle position. Initially after my trail mods, the pilot air screw was 3.5-4 turns out. The bike ran good except for hesitation 0-1/8 throttle. I went to 45 pilot and raised the clip one position (I know I broke the cardinal rule). Idle was good with air screw at 1.5-2 turns out but still some hesitation. I went down to 42 pilot air screw and the hesitation improved and was pretty much gone but the bike had trouble starting after riding and would bog and stall unless given lots of throttle. Then I dropped the clip back down to the middle position today and the hesitation is terrible. I’m not sure where to go next...??? The hard part is we have really tight single track here and I’m in the very bottom of the rpms and throttle most of the time, so I notice the hesitation. Listening to your bike ig sounded similar at 0-1/8 throttle but you never spent any time there; you quickly twisted it open through the range. The rest of my throttle range is good, crisp and pulls hard. I’d be curious if you hoped on your bike and tried to putt around in higher gears at minimal throttle what it would sound/run like. What do you think I should do next? Lectron carb??? BTW fuel ratio is 50:1. Thank you!

You're killing it man! Love the old CR's and I also admire how clean your bikes and workspaces are. I think your next project should be a CR500 AF build!

Come on cameron.all that effort and then when you get to changing needle clips you didn't have your bike fully warm and you didn't bother to show the audience just one clip leaner? Come ooooon caaaaamm, come ooooonnn

Thanks for the great video! Could you do one on cylinder porting as well?

Thanks for the video Cam, my bike is running so Crispy now!!!!

Maybe if you get a 4 stroke you could do a tuning vid on it #kx500

Once again an outstanding video Cameron.

I just bought my first dirt bike and I have been seeing your videos to fix mine they have helped me alot. I have a 2004 Honda crf250 bought it for 200$ me and my buddy got it to run the same day still has issues staring up.

I see the parts of cr250 you are working on the background, im so excited to see it on finish.

Thanks for the video!

Hey mate, i don't subscribe to many YouTubers but I've watched a few of your videos and they are top notch content! great video. liked & subscribed

nice wrx

Hey I need help fixing my carburetor on a YZ 125 I have a carb kit but I can’t do it

I moved my 2 stroke bike from 700 feet to 5000 feet. Do you think the airscrew does the trick or do I need to downsized Pilot/Main Jet? It is struggling for the fist 6K rpm, but from 6k on it is pretty normal, just a ton of smoke shoots out of the exhaust pipe.

My carb is 4mm then my stock but my jug is ported and bored but it’s has conditions of lean and rich spots gas and bogs down but when it gets up it doesn’t wanna go at first and takes a long to come down after. Could that just be to big of a carb or do I just need to re-jet the carb?

I've got a little problem when I Rev up with choke on it works perfect but when I turn of the choke and I Rev up it cuts of I really would appreciate some help

Also btw I absolutely love ur vids they are literally so helpful

I have a very big problem with my carb on my aprilia rs 50, it is running a dolloroto 14 12 m and I can only adjust the main jet and idle screw, there is no other jets or fuel mixture screws available., help would be much appreciated, also the bike bogs at full throttle under 3 k but if its at 3 k it won't bog at all HELP PLEASE!

Jetting..the only thing that isn't fucked up by the previous owner of the bike. It seized on the second day, but ran perfectly before that. I forgot to change fluids before riding it the first time that maybe be the reason, the cooling water was basically Rust broth with rust chunks in it ._. and the oil was like staring-into-the-abyss black so both had to be changed. Didn't take a look at the sparkplug before it died but it sure ran like hell and the owner said she runs a bit rich, which is a good thing because the engine only had like 200miles or to be a bit more precise about 340km on it. RIP Yamaha DT125R. bought myself a four-stroker now, ~which I crashed after 2 weeks.~ good thing is only the handlebar was crooked and had to be replaced but the one I got is way wider and feels super awkward to drive. Lost power though, low end is fine and it revs alright but top end power is even less, doesn't even manage 60mph or 100kph in 5th did 120kph before.

This is hugely helpful. Thanks man.

Great vid. Thanks

It had to be at least a day off shooting and more than that editing to create this video. Great to see the effort in the Moto community.

great vid nice one Cameron

what about the idle screw?

Ive been trying to figure out why my wheeler idles so weird i have a yamaha blaster yfs200 and it sounds like a car that has a huge cam in it the idke just bounces everywhere and it takes forever to idle down and one of the previous owners put a full fmf exhaust on it and they must not have changed the jets or tuned it and its running lean. Good thing i found this video before i blew my motor up.

I'm always putting on my screwdriver some small zip tie, and cutting them, with leaving some 2cm tail of it. It's very comfortable for counting revs of air screw. When air screw is screwed in, I'm just setting tail of zip tie to 12 o'clock, and start to regulate ;)

Good video but that engine braking hurts :(

Awesome video now i can finally tune my Husqvarna to mint jetting!

I am an old owner of a tiny two stroke honda mbx 50. I 've just watched your video and i think is THE BEST in all youtube in two stroke carb jetting. You spend a lot of time to do all the assembly and reassembly.

The Bible! The Bible! I can now officially say I have read (or watched?) The Bible!! Excellent!!

Thanks Juan!!

3 turns out at most, idle screw is just for the idle not for jetting

use a smaller main jet

lack of air

its really easy

Hello! Awesome video!! With tons of info ;) this helps a lot!!! Question: I have the Keihin PWKS 38 but i can´t find a chart (temperature/altitude) like the ones of the Keihin PWKS 36 (easy to find on ktm website for example). Can we use the jetting of the 36 for the 38?! And then do some tweaks on airscrew or needle maybe?

My 2001 yz125 clutch isn't disengaging. So when I have my clutch lever in and drop it into gear it stalls. Unless I'm already rolling. But when I stop it stalls out again and also pulls when I'm making a U turn with lever pulled in. Please help.

Thanks for the videos. I'm still learning but your videos have taught me a lot. Explaining everything about the carb and jets have been very helpful. If you could make a video for beginners on how to maintain your dirt bike would be awesome.

You've really done the hard part to show the extremes. Soon as you've gone to the extremes and then let us also listen to the test ride. To hear the "range" that it really affects. Cheers.

I've a problem jetting my 21mm dellorto, when i first tried with a main jet of 102 it was really too rich at idle, like really rich, it sputters at 6k rmp and doesnt get to the powerband, also the bike couldnt run stationairy. so i changed the main jet to a 98, still too rich, 94 still too rich, even a 90 was to rich, but i decided to make a run for it, so pushed until it sputters right before the poweband, but suddenly is got into the powerband and went to lik 12k rmp and stayed there even when i let go the trottle, like it was running really lean. i had to switch the key. So in short at idle it runs really rich like the choke is on but at high rmp it runs really lean. the airscrew is at normal 1.5 out and the clip from the needle is in the middle. Help me please

Great video, can tell you put a lot of effort into it. I’m experienced with jetting but I am having a hard time getting an ear for the 2 stroke lean/rich sounds, especially the needle position and main. If I hold my throttle at mid position the bike just wants to hit the powerband and take off. And it’s really hard to listen for a sputter when you’re flying on a 2 stroke. But good idea on starting rich and working your way lean. I could hear the sputter on your needle test but still I couldn’t really tell on the main jet test. I’m going to follow your technique though. Thanks for the vid

Billy Hall check you inner and outter basket for grooves. My buddys yz85 did the same thing so i popped those off filed them down then it went away.

By far the best video I've seen I like all your videos but I have an 04 kx250 i rebuilt it had it ported polished and the head domed and I'm struggling with the jetting I was running avgas 100ll and got water in it and had problems with it separating I'm going to try this thank you

My neighbors like to call the cops on me when I’m jetting

Great video. Great quality. Perfect

thank you so much now i can fix my bike. i fouled a plug earlier. its rich on the pilot jett. i gotta raise the clip one and back the air screw out a couple turns. 2001 cr125

I like this video, teach me how to jetting pilotjet and mainjet, how the sound will be effect if turn 2,5 air mixxing, but I try it to my 150px vespa.Thanks for this video.

Excellente video! Thankyou!!! Best video!!!

Thanks my bike was realy boging in mid an low gonna order some jets and spark plug

thank you very much, struggeling for a while with my bike to get the right carb settings, my bougie stays white (even when I'm using a main jet size 2 sizes lower than the size which doesn't even run good) hopefully someone here knows the cause

00:31 is exactly the same as my bike was running

Okay, so for tuning idle... Too Rich on the pilot screw= Slight bog to initial pinning of throttle/ idle drops too fast and sounds kind of thick.. Too Lean on the pilot screw= Quick throttle response but hangs before returning back to idle as well as starts idle "Tinging" before returning to idle rpms Just right on pilot screw= Quick throttle response, returns back to idle without tinging until almost back at idle, no hanging on throttle That sound correct? I wish you would have shown how it sounds on the lean side with the needle height. :\ By the way, What was the jump up in main jet from the 410 original? You first said "A few" then you said a "size or two"? Good video but would have like to hear more lean running? I don't think that a couple of passes running lean would hurt anything. Also, I think that it would have been easier to hear the rich conditions if you were on a smooth road. The bumps on the dirt made the throttle bounce. Keep in mind that I'm speaking from novice point of view. Thanks.

Thank you so much.

The lectron was hands down the best mod we ever did to the Ktm 300 better than porting or milling the head. It made the bike run soo good felt like it was getting perfect fueling everywhere in the throttle range.

anyone know what are the best settings for a 99 rm250?

Great video sir..

i am stuck with my bike -its a 2017 ktm 250sx and it sounds like its running fine but everytime i turn the bike off and let it sit for 10 mins or more when i comeback it wont start and needs a new plug. but if i turn it off and kick it over 3 mins later its fine.

it sounds lean after thinking about it but wouldnt that make it less likely to foul plugs

my bike is dieing as soon as i put in the choke, it is winter where i am right now, is rhe pilot jet to small?

Very good information thanks.

Hey I recently took my needle out and when I put it back in and started my bike is reving out like I'm holding the gas. What did I do wrong

Best best best

Hey my yz 250x runs amazing but it im going really slow in first to where the bike is about to stall out if i hit the throttle hard it bogs what adjustment should be made? Thanks for anyones input!

The main jet only affects from 3/4 throttle to full throttle, try changing the needle position to leaner

you shold build your wrx

Same here

My bike run just fine in summer.. Do I need to play with the little screw to increase gaz ratio for winter? (colder temperature) or the opposite? I want to do ice riding on the lake

What will a cracked carb boot do?

I'll have to use this video as a reference when fine tuning my RG250 Gamma. Loads of mods on that bloody bike. Scary fast too.

Paused at :13 to crack a cold one!

REALLY nice video ! helped me a lot thanks Cameron !

Never seen any of your videos until now but wow you have a legit channel. Spotless bikes, perfect shots, very in depth explanation of each lean and rich conditions. I’d like to see more of your shop, I see spare 3rd gen aluminum CR parts all over

Cameron... 2min, really? Do it again with having the exhaust already off and the boot still attached to the carb. Good vid thou!

La traduzione è complicata da comprendere. Ciao Grazie sei 1 specialista di motociclette

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