this guy should make videos on every thing he knows because he explains things so thourghly without 1 extraneous fact its literally the best how to video I have ever seen! Thanks for posting!
Finally someone who knows what he is talking about. Keep up the videos. The hot start trick on jetting help me so much. My bike runs like a beast now. And my air screw is at 1-7/8 out instead of 2.5 as set from honda. Much safer to run a little rich than lean. I'm totally amazed at his ability to explain carburetor. Help with my 2-stroke on another video also. Thanks again for being awesome.
never adjusted a carburetor before - watched your video after rebuilding my sons old secondhand carb(after watching another video) , and now it runs PERFECT ! Thank you. Great video.
@@dirtniron I have a 08 KTM 4 stroke I have the needle set at top clip and and fuel screw only 1 turn out and my bike is still running to rich what do I need to adjust to fix this? Thank you for the info
Oh man! I am glad that I found your video. I can't wait to get to the bike and readjust the air fuel ratio. I've been puzzled for a whole month. I would normally stop unscrewing at the highest RPM, then, adjust the idle screw. After watching your video, I realized that I had been adjusting it to run lean. This is probably going to solve the problem of hesitation during acceleration. Thank you scoo much!
I’m 14 and only have a tiny bit of experience with my dirt bike and couldn’t figure it out. My dad has a lot of experience but none with Honda. Thanks again for helping me out
@Dirt N Iron thank you so much for making these videos! I have owned my WR450F for only 3 weeks. Having never owned anything with a carburetor I ended up unscrewing the idle screw all the way out. Luckily I was able to take out the carb and re-screw the idle back in. Your videos have really helped me understand the carburetor and how to conduct maintenance on my bike.
I installed a R&D Racing Flex Jet in my Suzuki DRZ-400E and hung it off the metal feul inlet on the carburettor with a zip tie it is the best mod for on the go tuneability especially when going high and low altitudes i highly recommend this product to everybody just do it you won't regret it.
Great explanation! I bought a non running yz426f and rebuilt the carb and it back fired like crazy! After taking direction from this video however, my bike is much happier and pulls fat wheelies now !
My bike was sitting hurt for a month and when I got it running again I forgot all this process. Was looking everywhere for this vid because it’s the only that makes quick work of the tuning. Took me 5 mins after watching again 😅
I have the same bike with all these issues..... You explained this brilliantly, to the point where i know what i am doing! Lets see if it works though,,, wish me luck!!
Great tip (near the end) on the hot start with little or no response, meaning maybe too lean. That was very helpful in getting a KLX450R carb dialed in with a little more fuel mix. Thanks! (Prior to viewing and tweaking, hot start worked for hot starts, but still backfiring on shifts and trailing throttle.)
Dude this video couldn’t of popped up on my feed at any better time, just had my 2014 yz450f rebuilt top n bottom and I personally don’t think it idles how it should compared to before I had the rebuild but had no idea
100% on the money, before watching this I was left perplexed thinking the worst case scenario. now I know exactly what im listening for and how to dial them in and the bike is 100% on the money cheers for the helpful upload
Thank you so much man, I just bought a yz250f and I thought I got screwed over on Craigslist because the bike was not running the way it should’ve been and a part of me was scared to ride it but this video fixed all of my problems and I just wanted to thank you for this detailed video🙏🏻 definitely subscribing because I’m sure there is even more to learn that could help me out.
Thank you very much for this informative video I have no experience when it comes to bike maintenance I just got my first bike crf450r it wouldn’t idle on its on after watching this video and following these steps I was able to get it up and running correctly it wouldnt keep idle because it needed these adjustments as they weren’t correct and hot start made no difference in the idle which was how I figured out it wasn’t jetted correct and I was able to fix it thanks to you
Wanted to say thanks for the video brother. I bought a new carburetor and I could not get it running right. I followed what you said , turned the screw all the way in and back it off a little. And it’s now running. Thanks.
What exactly do you mean at 3:38 "raise the rpm a little bit higher with the idle screw"? I think my idle screw is not adjusted well in the first place. So how do I know where the idle screw position (a little bit higher than normal as you say in the video) should be in order to continue with the procedure?
I have an RPM gauge on my bike and it's recommended I have an idle around 1800 RPM. For this procedure approx how many RPM above 1800 should I aim for to begin? Thanks!
Hey Rado, I’ve bought my first bike about a month ago. It was a project and it was the first time I rebuilt a motor. To make a long story short, I did this rebuild with only UA-cam tutorial videos. Now she’s up and running and she’s finally getting the love she deserves. The bike is a 2006 KX250F. I’m having, I guess you can call it a bogging issue at mid-high rpm in any gear. Where the bike feels sluggish, then at times she’ll die on me and I have to wait a few minutes before the bike will start. I can’t tell if it’s too rich or too lean. I tried to set my aftermarket fuel screw exactly to this video. However, my bike increases in rpm instead of dropping around 2 - 2 1/2 turns out. If this is correct l, it never fixed my problem. The bike pulls very hard during test runs but there’s something not right with the fuel system, any suggestions? I’ll be riding at 496’ ASL around 15-25 degrees Celsius (59-69 Fahrenheit) When I opened the carb up I found: 180 main jet 55 Leak Jet 40 Pilot Jet 68 Starter Jet Needle Jet: 2nd last clip on the top. Thank you for the excellent content, I watch all of your videos and I’ve learned so much. You motovated me to get my first bike since I was a kid and I can’t wait to get this baby on the trails. Love from Newfoundland, Canada.
Hey Bobby, I would suggest to get jd jetting kit, they tested same bike you had and will give you best recommendation for jets. The kit is like $70-80 but it really does work, I have it on 3 bikes now. of course you can try to play with it and come to similar results.. but kit has it all, plus they have custom needles that gives you very smooth transition. try to raise the needle one clip and test, then maybe raise one more clip and see how it behaves. By raising needle you are making it richer, you allow more fuel in. if it gets worse then go opposite direction on the needle and lower her all the way down, and see what happens..
Dirt N Iron I played with the needle jet clip positions and found one where the bike doesn’t shut off! Jetting kit is on the way as well. Thank you again, Rado!
Dirt N Iron Hi Rado, I used the JD Jetting kit and found my bike is still shutting off. Usually it shuts off on a small uphill. I’m going to try to adjust the float height maybe? I hope your new dirt bike hunt is going well, looking forward to your next video.
what jetting are you running now? checking float height is good idea. I think you might still be little lean. which needle did you install and what clip?
Had to subscribe to give a small help, thanks to this video i now know exactly how to properly set my air/fuel screw aswell as the Idle one! Thank you very much!
@@dirtniron Quick question, when you say in the vid "Turning it out" and the RPM gets lower, on mine it does the opposite, if i'm 3 turns out it's quite high rpm. If i turn it down from 3 turns i get it lower and lower. 2.75 turns seems to be the best for me, right that part where it doesnt get higher, and doesnt get lower. Should i turn it back a half turn right before it starts to raise the RPM? So basicly, if i turn it out more, then the RPM rises higher. It's a Keihin FCR 37 (flat) carburetor Hope i made any sense!
Great job on explaining this. Some where in one of his videos he mentions putting in , I’m assuming an in line fuel filter, but I never saw that. Has anyone seen that? I’m curious as to where he installed it. Was it a 90 degree or straight etc
the adjustment of fuel screw depends on the design or model of the carburetor, whether fuel screw is located before the slide or after the slide, if the fuel screw's location is same as the video, turning clockwise is getting leaner while counter clockwise is richer that's why rpm is going down when adjusting the fuel screw counter clockwise, on the other hand, when the fuel screw is located before the slide, turning clockwise is going richer, and turning counterclockwise is going leaner that's why in this design if you turn fuel screw counterclockwise the rpm goes up. You can directly observe this when you turn fuel screw counterclockwise it's either the rpm goes up(leaner) or the rpm goes down(richer-same as the video) hope this helps if you're struggling tuning your carburetor.
When I screw the air/fuel screw in all the way and bring the idle up, as I bring the air/fuel screw out the revs are going up, not down. Any suggestions? Bike is a 144cc 4 stroke 🤷♂️
Stephen Windle I think you might need to switch you pilot/slow jet to a larger size. That’s what I’m doing to my crf250r. There’s a good video explaining ua-cam.com/video/kUw41sUQbTY/v-deo.html I’ll tell you if it works on mine
Thanks my bike would not want to start today at all so i just kept turning the screw till it did kick start and then when i finnaly had it running i turned the screw until it sounded just right👌, i have only been riding for 2 weeks now.
I adjusted mine the way you described and it runs great at idle great throttle response and revs up with hot start but when I go to ride when holding in clutch to stop and down shift it dies any suggestions
got my first dirt bike last year only got to ride it now because it was sitting and we moved to a place where we can drive it daily and keen as to ride it
Nice Video, If I may I’ll add something else to do with WR 450 or any other Carby 4stroke. I personally don’t like the after market fuel adjustment screw, this is why. I keep the OEM screw , adjust as required , generally if your jets are right size and clean , you will end up about 2.5 to 3 turns out on mixture screw. It is tricky to adjust OEM screw, but not that hard use a tiny screw driver BIT Now once the bike is running right your happy with mixer screw setting , put a blob of grease in the mixer hole, behind head of screw , then stuff a tiny bit of rubber / sponge in the hole behind the grease. 2 reason, stops the screw coming loose .they do and can fall out, or change the mixer setting, and the mixer screws can and do leak past the thread , screwing your mixer ever so slightly also, if it falls out it will stop, 👍. After market screw vibrate loose also, put a rubber band on it also.
Dude, this is an awesome video. I am having similar issues that you describe on my sons 2004 Yamaha wr250f. I am going to try all of these adjustments to see if it will clean up. thanks!
Shop manual says idle speed is 1700 rpm. Ridiculously high IMHP. Can't we make them tick over around 600? Great video. Watched it twice so far. Will look into the idle screw mod. Thanks
I took of my carb and cleaned it didn't take out jets and stuf just cleend it only removed fuel screw now i strugel to start my bike and adjust the carb bike wont idel its a kx450 2008 ,any tips
So when I tried this method on my xr 400, when I get to like three turns out the idle actually increases and keeps increasing the further I go...clean air filter, warmed up, just cleaned the carb and replaced all the gaskets on it, no indication of air leaks in the intake. So what's up with that? If I turn the fuel screw in it dies once you get past half a turn, so we would expect that, but why is the idle speed increasing the further I go out?
Problem is WR450F dirtbikes are now fuel injected. Does this still goes for the fuel injected? The muffler is getting red hot and people is telling me fuel or jetting is too rich making the muffler red hot. Thanks for the video.
Hi, thanks for the info, One question, with the screw all in and the right pilot jet, the engine Will die? Because mine, with all the screw in, still run, but with more high RPM
@@dirtniron With fuel injection now, it is a moot point.....but the guy that decided to put the idle mixture screw on the bottom of the carb on 4-strokes.....probably won't get to Heaven, will he?
Hello I have the same carburettor, but I have another issue When I accelerate and leave it normal , is starting to accelerate by itself like and to stop it is either I play with the thingy on the left or I press the cold hot starter from the right handle . I clean the jet and everything But the issue is still there Is like the air is to much or the mix is not alright But only when I accelerate and then I take the hand form it , instead of coming down is juts goes up but not to much
My 4-stroke bike starts pretty good cold. Sometimes 1st kick. But when it warm, it's hard to start, and it starts most reliably with half choke. What does that sound like to you? I'm thinking maybe the main jet is a little to big, or a little too small?
Hey buddy is the fuel air knob the only adjustment on these? I have a 17 crf230f and I can't get it to stay idling and it's hard to start up and keep running. I can get it to start full choke but then when I lower it to half choke or no choke it dies out. This has been an ongoing problem for a while where I've got it running and Stay running but it's had trouble on cold starts and staying running. I took the fuel petcock off as it was running in reserve but not on on. So it was clogged when in on position so I cleared the clog but now I'm still having trouble. Now I think I killed my battery from starting it so much and not staying running 🤬🤬 Also my bike only has one black knob above my carb. There is a small adjustment screw at the bottom of the carb on the face of it, one that you would adjust with a flat head driver
Help, I did everything you suggested, however, when I turn my fuel/air screw OUT it actually does the opposite. It starts to increase RPM, not decrease. Any thoughts why this is? And when I try to rev the engine, it bogs down and dies. However, it runs GREAT with the choke on. Confused. Any help would be great. Thanks.
I think my fuel screw needs adjustment but I've gone from a 48 pilot all the way down to a 40 and it still doesn't die when I'm all the way in. I had it running good with a different fuel screw with a 42 pilot but then the o ring snapped so put a new fuel screw in so I'm gonna try putting the old fuel screw back in and go with a 42 again as the tips are different on the two fuel screws I've got. Also when I pull my hot start in the bike dies? Any idea why that is? Thanks
I have a crf250r and it doesn’t idle without the choke? And I was going through the comments and didn’t see anyone with the same problem. Please help!!! Thank you!
Hey I always thought the hit start was the red knob beside the black Choke on the side of the carb? I have an 01 yz250f? Can you help me answer this question I've asked many other ppl, never with a definitive response
DirtNiron, i can't understand this method because most mechanics talks about finding HIGHEST rpm between rich and lean fuel screw adjustment. You doing opposite (finding lowest RPM). Can you explain who is right and who is wrong ?
He said to turn the idle a bit higher to create a lean condition then he turned out the pilot screw until the rpm drops, till then fine. But what about when he re adjust the idle screw to decrease it, would it not become a too rich mixture?
Should I adjust carb or throttle cable because the bike is running at high rpm it sound like I’m revving it but I’m not and the bike wants to just go fast and in 1st or 2nd it won’t cruise at slow speed I always have to pull the clutch in to go slow
I have a dr350 that will not idle reliably under 2500 rpm. Even fully warm. I rebuilt the carb several times put in a new plug check for air leaks I know it's getting fuel and I'm just almost out of ideas aside from compression or maybe some ignition issue. I think I'm a little bit rich now but I'm not sure I can make it perfect but maybe I'll watch this video and mess with my bike this weekend
I am not that experienced with dirt bikes and maybe carburetors are different from manufacturer to manufacture but I thought the choke brings more fuel into the carburetor and not air it's when you choke the engine you're choking the air flow off thereby increasing the vacuum which pulls more fuel out of the bowl and into the carburetor. If I'm wrong about this please tell me so I can correct my thinking I'm dealing with my own issues trying to get my bike running by rejetting it and it seems like everything I do fixes one thing and messes up something else and I'm just all over the place on this n i b b i pwk28 mm. Thank you
you are correct, choke works like that but I was talking about hot start and that works opposite way. Not every bike has a hot start but pretty much every bike has a choke. hope that makes sense
Hello! Your videos have been helping me put together my 2013 YZ250F your a big help! tuning the carb it seems okay but I believe it’s not 100% correct because when I pull in the hot start it just boggs or the idle deteriorates even if the fuel screw is turned 3+ it doesn’t change the hot start idol it boggs, can you please give me some pointers on how to fix this or what is the cause? Thank you!
this guy should make videos on every thing he knows because he explains things so thourghly without 1 extraneous fact its literally the best how to video I have ever seen! Thanks for posting!
thanks Patrick, glad you find the video helpful! super encouraging comment bro 👍👍
Finally someone who knows what he is talking about. Keep up the videos. The hot start trick on jetting help me so much. My bike runs like a beast now. And my air screw is at 1-7/8 out instead of 2.5 as set from honda. Much safer to run a little rich than lean. I'm totally amazed at his ability to explain carburetor. Help with my 2-stroke on another video also. Thanks again for being awesome.
@@ronaldcollins2852 glad it helps 👍👍
never adjusted a carburetor before - watched your video after rebuilding my sons old secondhand carb(after watching another video) , and now it runs PERFECT ! Thank you. Great video.
Thanks for sharing, i am glad it helps! 👍
@@dirtniron I have a 08 KTM 4 stroke I have the needle set at top clip and and fuel screw only 1 turn out and my bike is still running to rich what do I need to adjust to fix this? Thank you for the info
I’ve been struggling with my bike for a months to make it perfect this helped more than all other videos I watched🙏
Same here!!! Only days though...
Oh man! I am glad that I found your video. I can't wait to get to the bike and readjust the air fuel ratio.
I've been puzzled for a whole month. I would normally stop unscrewing at the highest RPM, then, adjust the idle screw.
After watching your video, I realized that I had been adjusting it to run lean.
This is probably going to solve the problem of hesitation during acceleration.
Thank you scoo much!
Good luck!
I’m 14 and only have a tiny bit of experience with my dirt bike and couldn’t figure it out. My dad has a lot of experience but none with Honda. Thanks again for helping me out
Now youre 18
@East Coast Lithics and improved his life by switching to Honda. 😂
Now you're 19
This his such a good demo that I bookmarked into my tech how to folder, It's well choreographed, clear and concise. Thank you!
thank you, glad it helps!
@Dirt N Iron thank you so much for making these videos! I have owned my WR450F for only 3 weeks. Having never owned anything with a carburetor I ended up unscrewing the idle screw all the way out. Luckily I was able to take out the carb and re-screw the idle back in. Your videos have really helped me understand the carburetor and how to conduct maintenance on my bike.
glad it helps! have fun with your wr!
After many many days spent looking for a good video on this topic i have struck gold thx soo much
Glad you found it helpful!
My family has DRZ 125L that is having trouble idling. We've tried so many things but nothing was working.This video was so helpful!
I installed a R&D Racing Flex Jet in my Suzuki DRZ-400E and hung it off the metal feul inlet on the carburettor with a zip tie it is the best mod for on the go tuneability especially when going high and low altitudes i highly recommend this product to everybody just do it you won't regret it.
Great video, he knows his stuff. I adjusted my yz250f just the way he explains. WOW, throttle response is amazing, what a difference from before.
Right on! Glad it helped, thanks for sharing Neil!
Hey could u priv message me where the fuel screw is if it's a stock fuel screw
I'm about to go adjust my yz250f ... I'm excited!!!🙂
Great explanation! I bought a non running yz426f and rebuilt the carb and it back fired like crazy! After taking direction from this video however, my bike is much happier and pulls fat wheelies now !
thanks, glad it helps!
Hahahah just did the same over the last weekend. 😁 Got a non running 426. 😃
My bike was sitting hurt for a month and when I got it running again I forgot all this process. Was looking everywhere for this vid because it’s the only that makes quick work of the tuning. Took me 5 mins after watching again 😅
right on, glad it helps!
I have the same bike with all these issues..... You explained this brilliantly, to the point where i know what i am doing! Lets see if it works though,,, wish me luck!!
Glad it helped, good luck!
Great tip (near the end) on the hot start with little or no response, meaning maybe too lean. That was very helpful in getting a KLX450R carb dialed in with a little more fuel mix. Thanks! (Prior to viewing and tweaking, hot start worked for hot starts, but still backfiring on shifts and trailing throttle.)
Glad it was helpful!
"stay motivated, see you later" only reason I sub. Staying motivated when doing any work my man love it.
Thanks for the sub! Stay motovated my friend ;)
I can’t think of the right words to describe how much this video helped me so I will just say thank you!
Glad it helped!
i think this is the 5th time i look at this video. always helps me. thanks
Glad to hear that Anton 👍
Thank you. I've read about this process, but it didn't make sense until I watched this video.
thanks Daniel, glad it helps!
BOOM! Glowing pipe and backfiring sorted! Thanks Rado!
Glad to help!
Thank you for this video mate! It's very clear and easy to understand. Now have a job for my WR450 tomorrow!
Cool Mate, glad it helps!
Thank you very much for taking the time to help everyone! Your an awesome person!!
thanks Michael, appreciate it :)
Dude this video couldn’t of popped up on my feed at any better time, just had my 2014 yz450f rebuilt top n bottom and I personally don’t think it idles how it should compared to before I had the rebuild but had no idea
Never watched such a simple and informative video top notch stuff man
cool, glad you like it! thanks
Woah, this is what i'm looking for. Thank you!
welcome ;)
Was it making a puff noise when you rev it and try to ride bc mine is doing that them shutting off
@@l3dbeats586 too much air is what it sounds to me
100% on the money, before watching this I was left perplexed thinking the worst case scenario. now I know exactly what im listening for and how to dial them in and the bike is 100% on the money cheers for the helpful upload
cool bro, glad it helps!
Thank you so much man, I just bought a yz250f and I thought I got screwed over on Craigslist because the bike was not running the way it should’ve been and a part of me was scared to ride it but this video fixed all of my problems and I just wanted to thank you for this detailed video🙏🏻 definitely subscribing because I’m sure there is even more to learn that could help me out.
cool bro, I am glad it helps! congrats to your purchase, yz250f is great bike!
Thank you very much for this informative video I have no experience when it comes to bike maintenance I just got my first bike crf450r it wouldn’t idle on its on after watching this video and following these steps I was able to get it up and running correctly it wouldnt keep idle because it needed these adjustments as they weren’t correct and hot start made no difference in the idle which was how I figured out it wasn’t jetted correct and I was able to fix it thanks to you
Right on Giovanni, glad it helps! Have fun on your bike 🤙
Wanted to say thanks for the video brother. I bought a new carburetor and I could not get it running right. I followed what you said , turned the screw all the way in and back it off a little. And it’s now running. Thanks.
Thanks Ryan, glad it was helpful! 👍
Lookin now at others reviews,, wish i saw this years ago!!!!! Thnk you!! Youre like the bike whisperer!!!
Glad it was helpful!
This video was key to getting my 2001 WR250f to start with one kick...
cool man, glad it helps!
Wow this is a really helpful video, got a 2008 wr250f recent practically brand new. I'll definitely be using these tips when tuning my carb 💯👌🏾
This video saved me sooo much time. THANK YOU!!
welcome Bradley! glad it helped
What exactly do you mean at 3:38 "raise the rpm a little bit higher with the idle screw"? I think my idle screw is not adjusted well in the first place. So how do I know where the idle screw position (a little bit higher than normal as you say in the video) should be in order to continue with the procedure?
raise it higher than normal, just listen to the engine and adjust it so it has high idle..
I have an RPM gauge on my bike and it's recommended I have an idle around 1800 RPM. For this procedure approx how many RPM above 1800 should I aim for to begin? Thanks!
On point I just fixed my bike in like ten min was about to take it to the shop many thanks my guy🤘👍
right on, glad it helped!
Legend brother...thank you so much. After doing all the free mods. This was key to fix the back firing
right on, glad it helps!
Hey Rado,
I’ve bought my first bike about a month ago. It was a project and it was the first time I rebuilt a motor. To make a long story short, I did this rebuild with only UA-cam tutorial videos. Now she’s up and running and she’s finally getting the love she deserves.
The bike is a 2006 KX250F. I’m having, I guess you can call it a bogging issue at mid-high rpm in any gear. Where the bike feels sluggish, then at times she’ll die on me and I have to wait a few minutes before the bike will start. I can’t tell if it’s too rich or too lean.
I tried to set my aftermarket fuel screw exactly to this video. However, my bike increases in rpm instead of dropping around 2 - 2 1/2 turns out. If this is correct l, it never fixed my problem.
The bike pulls very hard during test runs but there’s something not right with the fuel system, any suggestions?
I’ll be riding at 496’ ASL around 15-25 degrees Celsius (59-69 Fahrenheit)
When I opened the carb up I found:
180 main jet
55 Leak Jet
40 Pilot Jet
68 Starter Jet
Needle Jet: 2nd last clip on the top.
Thank you for the excellent content, I watch all of your videos and I’ve learned so much. You motovated me to get my first bike since I was a kid and I can’t wait to get this baby on the trails.
Love from Newfoundland, Canada.
Hey Bobby, I would suggest to get jd jetting kit, they tested same bike you had and will give you best recommendation for jets. The kit is like $70-80 but it really does work, I have it on 3 bikes now. of course you can try to play with it and come to similar results.. but kit has it all, plus they have custom needles that gives you very smooth transition.
try to raise the needle one clip and test, then maybe raise one more clip and see how it behaves. By raising needle you are making it richer, you allow more fuel in.
if it gets worse then go opposite direction on the needle and lower her all the way down, and see what happens..
Dirt N Iron I played with the needle jet clip positions and found one where the bike doesn’t shut off! Jetting kit is on the way as well. Thank you again, Rado!
sounds good Bobby. let me know how it works!
Dirt N Iron Hi Rado, I used the JD Jetting kit and found my bike is still shutting off. Usually it shuts off on a small uphill. I’m going to try to adjust the float height maybe? I hope your new dirt bike hunt is going well, looking forward to your next video.
what jetting are you running now? checking float height is good idea. I think you might still be little lean. which needle did you install and what clip?
Had to subscribe to give a small help, thanks to this video i now know exactly how to properly set my air/fuel screw aswell as the Idle one! Thank you very much!
cool, glad it helps! welcome on board!
@@dirtniron Quick question, when you say in the vid "Turning it out" and the RPM gets lower, on mine it does the opposite, if i'm 3 turns out it's quite high rpm. If i turn it down from 3 turns i get it lower and lower. 2.75 turns seems to be the best for me, right that part where it doesnt get higher, and doesnt get lower.
Should i turn it back a half turn right before it starts to raise the RPM?
So basicly, if i turn it out more, then the RPM rises higher. It's a Keihin FCR 37 (flat) carburetor
Hope i made any sense!
Great job on explaining this. Some where in one of his videos he mentions putting in , I’m assuming an in line fuel filter, but I never saw that. Has anyone seen that? I’m curious as to where he installed it. Was it a 90 degree or straight etc
the adjustment of fuel screw depends on the design or model of the carburetor, whether fuel screw is located before the slide or after the slide, if the fuel screw's location is same as the video, turning clockwise is getting leaner while counter clockwise is richer that's why rpm is going down when adjusting the fuel screw counter clockwise, on the other hand, when the fuel screw is located before the slide, turning clockwise is going richer, and turning counterclockwise is going leaner that's why in this design if you turn fuel screw counterclockwise the rpm goes up.
You can directly observe this when you turn fuel screw counterclockwise it's either the rpm goes up(leaner) or the rpm goes down(richer-same as the video) hope this helps if you're struggling tuning your carburetor.
When I screw the air/fuel screw in all the way and bring the idle up, as I bring the air/fuel screw out the revs are going up, not down. Any suggestions? Bike is a 144cc 4 stroke 🤷♂️
Stephen Windle I think you might need to switch you pilot/slow jet to a larger size. That’s what I’m doing to my crf250r. There’s a good video explaining ua-cam.com/video/kUw41sUQbTY/v-deo.html I’ll tell you if it works on mine
thanks a bunch for making this! just got a 450 ktm smr and your videos have helped me lots to understand the FCR carb!
Glad it helped! thanks Alex!
wooow thanks a lot man my idle was staying high sometimes and I would never have guessed it was the hotstart ! 👍🏻
Right on man I’m glad it helped
Thanks my bike would not want to start today at all so i just kept turning the screw till it did kick start and then when i finnaly had it running i turned the screw until it sounded just right👌, i have only been riding for 2 weeks now.
cool Vince, glad it helps. take it easy!
I adjusted mine the way you described and it runs great at idle great throttle response and revs up with hot start but when I go to ride when holding in clutch to stop and down shift it dies any suggestions
Very informative, I appreciate the help. I’m trying to tune my carb and this helped a bunch.
Thanks, glad it helps 👍
Thx after 4 years i finally got it right
got my first dirt bike last year only got to ride it now because it was sitting and we moved to a place where we can drive it daily and keen as to ride it
Nice Video, If I may I’ll add something else to do with WR 450 or any other Carby 4stroke.
I personally don’t like the after market fuel adjustment screw, this is why. I keep the OEM screw , adjust as required , generally if your jets are right size and clean , you will end up about 2.5 to 3 turns out on mixture screw. It is tricky to adjust OEM screw, but not that hard use a tiny screw driver BIT
Now once the bike is running right your happy with mixer screw setting , put a blob of grease in the mixer hole, behind head of screw , then stuff a tiny bit of rubber / sponge in the hole behind the grease. 2 reason, stops the screw coming loose .they do and can fall out, or change the mixer setting, and the mixer screws can and do leak past the thread , screwing your mixer ever so slightly also, if it falls out it will stop, 👍. After market screw vibrate loose also, put a rubber band on it also.
thanks for sharing Ben, appreciate it!
Dude, this is an awesome video. I am having similar issues that you describe on my sons 2004 Yamaha wr250f. I am going to try all of these adjustments to see if it will clean up. thanks!
hope it helps, if not then maybe you need to try different jets. Good luck!
Amazing work! Keep up the good work. The video is very good and informative :)
Thanks man!
I agree totally
Praise Chapel Romania. Sector 5. Great video my man. God Bless
Man this video is awesome! Could not have come at a better time. Thanks a lot!
That's cool! I am glad it helps. ;)
What is the order of the spring o-ring and washer on the after market screw? Websites show it differently... 😅
Shop manual says idle speed is 1700 rpm. Ridiculously high IMHP. Can't we make them tick over around 600?
Great video. Watched it twice so far. Will look into the idle screw mod. Thanks
This guy is pretty good. Made it simple for me.
Glad it was helpful. Thanks Pat
I keep coming back to this for tuning
thanks, glad it helps!
I took of my carb and cleaned it didn't take out jets and stuf just cleend it only removed fuel screw now i strugel to start my bike and adjust the carb bike wont idel its a kx450 2008 ,any tips
Any tips on what to do if the idle adjustment screw won’t spin either direction?
So when I tried this method on my xr 400, when I get to like three turns out the idle actually increases and keeps increasing the further I go...clean air filter, warmed up, just cleaned the carb and replaced all the gaskets on it, no indication of air leaks in the intake. So what's up with that? If I turn the fuel screw in it dies once you get past half a turn, so we would expect that, but why is the idle speed increasing the further I go out?
How do you test the if it's rich if you do not have a hot start?
I haven’t rode my dirt bike for almost 2 years man I miss it
Problem is WR450F dirtbikes are now fuel injected. Does this still goes for the fuel injected? The muffler is getting red hot and people is telling me fuel or jetting is too rich making the muffler red hot. Thanks for the video.
Hi, thanks for the info, One question, with the screw all in and the right pilot jet, the engine Will die? Because mine, with all the screw in, still run, but with more high RPM
The most clear idle adjustment video I've seen.....
thanks Tom, glad you see it that way ;)
@@dirtniron With fuel injection now, it is a moot point.....but the guy that decided to put the idle mixture screw on the bottom of the carb on 4-strokes.....probably won't get to Heaven, will he?
Hello
I have the same carburettor, but I have another issue
When I accelerate and leave it normal , is starting to accelerate by itself like and to stop it is either I play with the thingy on the left or I press the cold hot starter from the right handle .
I clean the jet and everything
But the issue is still there
Is like the air is to much or the mix is not alright
But only when I accelerate and then I take the hand form it , instead of coming down is juts goes up but not to much
Hi rado, rpm doesn’t stay up when I push hot start ,it raises for two seconds then goes down.
Do you know why??
Thanks
Yehya Rf not really sure, how does it run otherwise?
My 4-stroke bike starts pretty good cold. Sometimes 1st kick. But when it warm, it's hard to start, and it starts most reliably with half choke. What does that sound like to you? I'm thinking maybe the main jet is a little to big, or a little too small?
After years,,, my 450 is dialed in!!!!! Thnx
welcome ;)
Hey buddy is the fuel air knob the only adjustment on these? I have a 17 crf230f and I can't get it to stay idling and it's hard to start up and keep running. I can get it to start full choke but then when I lower it to half choke or no choke it dies out. This has been an ongoing problem for a while where I've got it running and Stay running but it's had trouble on cold starts and staying running. I took the fuel petcock off as it was running in reserve but not on on. So it was clogged when in on position so I cleared the clog but now I'm still having trouble. Now I think I killed my battery from starting it so much and not staying running 🤬🤬 Also my bike only has one black knob above my carb. There is a small adjustment screw at the bottom of the carb on the face of it, one that you would adjust with a flat head driver
Help, I did everything you suggested, however, when I turn my fuel/air screw OUT it actually does the opposite. It starts to increase RPM, not decrease. Any thoughts why this is? And when I try to rev the engine, it bogs down and dies. However, it runs GREAT with the choke on. Confused. Any help would be great. Thanks.
Im having the exact same problem, the rpm goes up. Maybe you figured it out?
Same here
Clean your carb
I think my fuel screw needs adjustment but I've gone from a 48 pilot all the way down to a 40 and it still doesn't die when I'm all the way in. I had it running good with a different fuel screw with a 42 pilot but then the o ring snapped so put a new fuel screw in so I'm gonna try putting the old fuel screw back in and go with a 42 again as the tips are different on the two fuel screws I've got. Also when I pull my hot start in the bike dies? Any idea why that is? Thanks
not quite sure why it dies with the hot start.. try to dial it in first, make sure its not lean and do it again
I have a crf250r and it doesn’t idle without the choke? And I was going through the comments and didn’t see anyone with the same problem. Please help!!! Thank you!
Perfectly explained! 10/10
So, when I turn out the screw on my wr250 (2001) the rpm gets (a lot ) higher instead of lower. What could be wrong ?
Can you please give me advice on my Tao Tao 125cc four stroke carb change n adjustment
I am sorry I am not familiar with tao tao, but the system should be the same or very similar
Such a great channel, keep up the great work 👍🏻
Thank you! Will do!
Hey I always thought the hit start was the red knob beside the black Choke on the side of the carb? I have an 01 yz250f? Can you help me answer this question I've asked many other ppl, never with a definitive response
that could be on older models, I am not sure without seeing it
Shouldn't you set the idle mixture screw for highest idle speed, not lowest?
Probably you mean the air screw on a two stroke
@@joselitobrigante for four stroke do i need to set the highest idle speed or lowest? i dont understand
DirtNiron, i can't understand this method because most mechanics talks about finding HIGHEST rpm between rich and lean fuel screw adjustment. You doing opposite (finding lowest RPM). Can you explain who is right and who is wrong ?
He said to turn the idle a bit higher to create a lean condition then he turned out the pilot screw until the rpm drops, till then fine. But what about when he re adjust the idle screw to decrease it, would it not become a too rich mixture?
@@hydarmbm3456 strange method anyway
i have a kx250f 2016 fuel injected and idle is perfect but when i ride it its high revs the whole time any idea what the problem is
Should I adjust carb or throttle cable because the bike is running at high rpm it sound like I’m revving it but I’m not and the bike wants to just go fast and in 1st or 2nd it won’t cruise at slow speed I always have to pull the clutch in to go slow
you need to have a free play on your throttle and then adjust the idle on the carb.
You should do a video about float height it's the mostly commom problem on carbs
Sir, why does my bike starts on using choke in cool engine,? Please, reply.
Wow was I wrong !! I needed a 48 size pilot jet now my bike runs great. Yes I was a dope, At least I can admit it when I'm wrong.
cool! glad you got it running right, good luck Ron!
If the fuel screw is too far in, does your throttle response worsen? 6:45
This video really helped me out thank you! Very easy to follow instructions - thank you sir!!
you got it Ron, I am glad it helped!
Hi, can I see the color of your complete wr spark plug?
Precisely my issue! Got it adjusted and running like a champ. 05 YZ450F. Thanks!
thanks for sharing Clint, I am glad it helped!
dude ur videos are so inndept and wheel teached i could watch u all day
Thanks brother, glad you find it helpful! Welcome on board 😉
must you go up a bigger jet if you change from stock airbox to open aircone airfilter?
I did JD kit, but it does make sense to go little bigger
I have a dr350 that will not idle reliably under 2500 rpm. Even fully warm. I rebuilt the carb several times put in a new plug check for air leaks I know it's getting fuel and I'm just almost out of ideas aside from compression or maybe some ignition issue. I think I'm a little bit rich now but I'm not sure I can make it perfect but maybe I'll watch this video and mess with my bike this weekend
I am not that experienced with dirt bikes and maybe carburetors are different from manufacturer to manufacture but I thought the choke brings more fuel into the carburetor and not air it's when you choke the engine you're choking the air flow off thereby increasing the vacuum which pulls more fuel out of the bowl and into the carburetor. If I'm wrong about this please tell me so I can correct my thinking I'm dealing with my own issues trying to get my bike running by rejetting it and it seems like everything I do fixes one thing and messes up something else and I'm just all over the place on this n i b b i pwk28 mm. Thank you
you are correct, choke works like that but I was talking about hot start and that works opposite way. Not every bike has a hot start but pretty much every bike has a choke. hope that makes sense
@@dirtniron oic now.Thanks for the reply.
Hey is their another way I can turn the red nob thingy I don’t have that and idk how to turn it?
Very small screw driver that can fit in there, not a lot of room. Get new fuel screw it makes your life way easier
Hello! Your videos have been helping me put together my 2013 YZ250F your a big help! tuning the carb it seems okay but I believe it’s not 100% correct because when I pull in the hot start it just boggs or the idle deteriorates even if the fuel screw is turned 3+ it doesn’t change the hot start idol it boggs, can you please give me some pointers on how to fix this or what is the cause? Thank you!
I have a 2004 RMZ250 my question is should there be a filter on the gas line going to the carburetor or not
there is one in the tank, but I would use one more on the fuel line just to be sure..
What does it mean if i have the idle good and when I pull the hot start it stalls.
How high to put your idle adjustment screw