If you rev engine it should return to idle RPM easily. If they dip below idle, try leaning the pilot screw. If they hang and take a while to return, try enriching the pilot screw.
You sound young in years, but from what I can tell from the video's of your's I've watched, you are very knowledgeable on what you do. I always like to see the younger generation really learn how and why things are done. Great job and doing what you do.
Damn haha, thanks for the video. i just found out that i've been adjusting my air screw instead of what i thougt was a fuel screw. I was getting really confused with the reversed outcome of turning it in and out and choking out the bike. You learn something every day.
I searched so long for this information. No one i ever asked could tell me how to know if its adjusted correctly (besides checking the spark plugs which still doesnt tell me what to do) This is a perfect tutorial. Short and full of information. Thanks
I dunno where you came from but thank you for just getting to the point without all the look at me I'm wasting more of your time when if you had to go looking for answers and your already frustrated useless chit chat most people put us through. Very well done
Great video. I have a rough understanding of carbs, and this video helped me to figure out exactly what each screw does Now my little 110 ATC is swamping like never before.
Matthew MC Repair-he doesn't even know does he What a refreshing oasis this video is. Mat probably thinks people that don't know what they're talking about would never waste their time making videos. YOU WOULD BE VERY WRONG MAT Most of the Honda XR 250 videos posted, I swear to God I don't know how these people find the door to get out of the house in the morning. Most of these videos are posted by people who bought an old dirt bike, put gas in it, kicked it and it started. THIS, THEY ARE CERTAIN MAKES THEM A CERTIFIED MASTER MOTORCYCLE MECHANIC. THANK YOU AGAIN MAT.
@MegaStick93 Do you hear the terminology this man is using? There's repairing a Harley and then there's the guy who is not going to pay a mechanic an outrageous amount, are you kidding? He had a Schwinn growing up, never needed any help with that. What's the difference? Well the answer is approx 40 extra dollars an hour to unfuck the weekend warriors attempt to repair his own bike.
@@OO7RX7 Are trying to spell "please"? How can that be an issue with today's computer technology? Do you see the red line under half of the your words you type? Ya that's not for inflection E.B. White. Just right click them bastards. No need to thank me just pass it on.
I typically adjust each carb 1/2 turn at a time. I try to reach peak & smooth idle RPM as a starting point. Sometimes, if any hesitation or bogging occurs upon acceleration, the idle mix may have to be richened slightly.
Thanks for the easy to understand directions for tuning a carb. I grew up on carbs, but never knew enough about them to fine tune them. It was factory or get someone else LOL
Wow excellent vid. Dad just bought the Boyz there first atv’s. 70cc witch is really tiny and cold blooded and a 125cc for my 7yr old. 70 hard start. 125 no problem. Half turn thanks to u and is so easy to start it’s almost the same as the bigger 125. U Da MAN!!!!!
I really needed this, I have a Honda 250 1986 and it barely catches up with the RPM, I think the fuel is too lean cause it barely even uses fuel too. I am going to give this a try in the morning, thank you very much!
Your video saved me soo much trouble and concern by narrowing down the problem with my bike, Thanks! (specially the part you explain if screw is by the motor its fuel - not air)
Hey man.... Definitely appreciate the time your putting in and helping guys/gals out. If it wasnt for your video I wouldnt even know where to start. Thank you again! 👌
Very helpful thx! You get to the point, not much excess rambling or chitchat about off topic crap. Good explanation and demo of screw locations and effects on idle. I liked the screw comparison at the end.
Master 52 year mechanic here. You explained this exactly correct. It is that simple and is a matter of a person understanding the absolute reality here. Heres one of my harleys and its situation. It is a 1997 fatboy with the 1340 Vtwin. It has the mikuni 42 on it right now. Its air mixture screw is set perfect and only one full turn out. These are supposed to set at one and a half turns up to two full turns out, so why does mine only give me the best performance at only one turn out? Has to be because my pilot jet must be very small. But doesnt matter because go figure. No black smoke comes out of my exhaust at quicks revs, plus no hesitation occurs at all and this engine has more power than I could ever need. Why change what works perfect? I know because of this that that pilot just must be as tiny as a 38 instead of the 42 jet. Im saying this, if something works and you have to most power for what your engine is, leave it alone
@@HTMR Its a new chinese made version of the original mikuni hsr 42/TM42. Before I installed it I checked the float by holding it upside down and blowing through it and holding it right side up and doing same and only checked the size of the secondary jet through the float bowl nut that is in the center of these models and it has a 160 jet, but to see the pilot jet would require removng the float bowl. The way I have the air mixture adjusted at only one turn out is against all the averages in where others with same use the 1 1/2 to 1 3/4 turn out. It has the stock 3.5 diameter cylinder with the 4 and 1/4 inch stroke engine. But no balck smoke on revs and no hesitation, so the shoe fits
Damn! This was the cat's meow! Perfect video making perfect sense...thank you so much for your help! My carb Suzuki DR200 has the idle screw on the bottom of the carb...what a pain in the tush to get at it! Mine seemed to be happy at about 2-1/2 turns...
Great explanation. I've been adjusting screw to get bike to run well, but did not know what to shoot for (other than trying to avoid lag in throttle). Thanks.
This didn't help me find my particular fuel/air screw (2002 Yamaha big bear 400) but it definitely helped me realize that my running problem 90% sure is the fuel/air screw not being set right. I'll take it in to this nice mechanic and maybe he can help me find it and get it set right. I believe it's fuel/air screw because it idles perfectly well. Whenever I take it for a spin though my four wheeler sputters while revving up until I get to full throttle where it will run perfectly fine which I believe is when a main jet or something kicks in.
Thanks for sharing. I needed to find out what a pilot air screw was on a 15 hp twin cylinder Kawasaki Lawn Mower engine and this did a good job of explaining it. A lot of these lawn tractor engines do not have any adjusting screws on them these days.
Great video! Quick question. I cleaned and rebuilt the carbs on my Virago 1100. I synched them last night and the bike seems to be running well. However, when I went to adjust the pilot screws, tightening the screw (on the front carb) actually made the revs go up after a certain point instead of down like I would have expected. Is that normal? I figured less gas would bring the revs down.
Joshua, seems like your initial setting was to rich and you leaned it out resulting in an RPM increase. You want to tune both little by little until you reach max RPM and smoothest idle.
Hey, I did it! I started with the rear carb this time and tightened it until the engine started to stumble, then turned it a half turn back and then I did the same on the front carb with no issues. Thanks again for your help and the great video.
I took off my carburator to clean it took it all apart put it back and my atv don't start any more and the problem is that I didn't measure the turns how do you measure the brass if it don't start you said it needs to be a hot temperature
I hate when they are underneath. In this case I use a screwdriver bit and hope I don't burn myself. Otherwise motion pro makes a nice 90° screwdriver that is crazy expensive.
I think it may help the viewers if you mentioned, that most two strokes have an air screw on the inlet (airbox) side, and most four strokes have a fuel screw on the exhaust side. Both doing the same thing but vice versa, one adjusting the amount of air entering the carb and one allowing more fuel into the combustion mix. Most bike owners should know if they have a two stroke or four stroke, and it may help them locate the screw.
+Julian UK Good point. However, there are plenty of 4 strokes out there that have air screws on the carb. Also, some amal carbs on triumphs have and air screw on engine side. Best thing to do is pull the screw and look at the tip. Blunt tip is air and pointy is fuel.
Thank you for the video. Did not know if the screw on my carb was air or fuel. The last part of the video perfectly explains it by comparing an air screw against a fuel screw. Mine is fuel.
Holy cow trying to figure out the difference between the fuel screw in the air fuel screw you get 20 different answers on this thing I just want to know if you turn the "fuel screw" in which is at the bottom of the carburetor does it give me more fuel or if I turn it out does it give me more fuel that's all trying to figure out.
Subscribing and 100 more if I could!. Just bought a bike pretty much starting new on motorcycle stuff and riding ....you sr are a great help! Thank you so much
well i tried working on it (as well as a crf80) and they have an air mixture screw but no fuel screw. and i didnt really want to tear into the whole carb just yet, so i decided to just block out the other "intake" i made so now they are back to stock. if i want to make these bike faster ill just save money for the big stuff (suspension, 143cc bore kits,exhaust) anyway thanks for your help man!
Your biggest concern will probably be the main jet. I'm not familiar with those bikes. Put the pipe on and see where your fuel screw ends up. Also do a plug chop for main jet.
Have a 1986 CB nighthawk. Needs a ton of choke to start and warm up. The issue is once it's warm and I've been riding for a while, then it wants to cut out when you slow down or stop. Have to rev at a stop to keep it going.
I believe you are referring to the idle speed. If so, there should be a black plastic knob that you can turn to adjust to desired idle speed. The knob is attached to a flexible black tube that runs to the carb. The knob should be easy to access. Let me know if that helps.
Great video exactly what I was looking for. I’m adjusting on a two cylinder so slightly more tricky I assume? The ninja 250r is a fuel adjust. I’ll try 1.5 out on each then adjust one at a time too see if I hear a difference. Thank again mate Regards Jimmy
I did replace the needle and seat. It could that the level is to high. I think I figured it out it only does it when its on the side stand. Those old bikes lean way over on the stand, and a combo of hi level in the bowl. Thanks for the response.
You need the engine and carburetor at full operating temperature for the adjustment, like after a 30 minutes ride. This is valid for any engine regardless of the number of cylinders. Also, a Colortune plug (no affiliation) would make finding the sweet spot easy.
My 750 spirit shadow isn't staying on while choke is pushed in, my jets aren't clogged and itl stay running when gassed a lit bit not too much, then it starts to sputter and some sparks come out the pipes
Thanks for this. Been wrestling with an issue with my Honda GX620 engine for years. Finally found/realized there is a pilot air screw on the inlet side. Knowing that this is what it is, and screwing in richens up the mixture is the key. It ran better when I did this, but I wanted to be sure, as it seemed counter intuitive that in is richer. Now knowing that what I was doing makes sense, I can tweak it a bit more, plus feel confident that I might finally have this solved. Many thanks again for a clear, concise, and no BS video.
I noticed you were riding in some deep water in the vid on your channel. You might want to check the airbox & filter for water. Also, pull the float bowl drain and see if you have water in the gas.
Great Video, Thanks man, now i realized, i had backwards understanding of this screw, i thought that's control air, but i know now that control fuel, that's why my bike always have lean conditions
The air screw you replaced meters air to the pilot circuit. The pilot jet supplies fuel to pilot circuit and is located in the float bowl. I would check for vacuum leaks. It's easy and I have a vid on that. Next, I would pull the carb and verify pilot jet, main jet, needle, & needle clip position and compare to stock. You'll probably find a leaner pilot jet in there. Also, a leaner needle clip position can to some extent provide a bog like you have.
very cool video dude explained alot. i've recently just had to change my complete engine on my honda shadow 700.6 weeks later finally done only 1 problem my bike is chugging in the low gears checked all piping from carb to make sure theres no excess air in take. so do you think i should try with the air/fuel screw? cud that b causing the chugging??
You have a problem elsewhere. Vacuum leaks, bad choke plunger seal, high float level, etc.....it is pulling fuel from another source, or pilot jet is too big.
Matt, thanks for the video. I have an xr400r which idles fine, but dies immediately after stabbing the throttle from idle. I can keep the bike from stalling if I ease the throttle. Once in higher rpms, I can stab and it's just fine.
The fuel mixture screw only affects idle. The pilot jet affects up to 1/8 throttle. Your modifications will probably require a needle clip position and main jet change. Start by tuning the fuel screw correctly.
Good video man. BTW they make and sell a rubber plug for those air/fuel mixture screw tubes you can put in the hole after drilling it out. As you said they may not be necessary but I put them in my bike anyway to keep the trash out.
The best way I adjust the pilot air screw is with a vacuum gauge after it's warmed up and it will be perfect. Some of your older street bike had as many as 4 carbs to adjust and with out a vacuum you can never get them set correctly.
Hi Matt, thanks for posting this video, for the first time I finally understand! I took notes and everything!! In your opinion, do you normally have to change jets if you take the airbox off and stick a filter on? I've got my project chinese 125 running now, (thanks to you) but it seems to be distinctly lacking power, nothing else has been altered (engine/carb-wise) except the airbbox removal..
I know this video is ancient and what you did is correct. I do believe your final determination if your mixture is correct is by plug color. Have mine a dark copper.
I have 2006 yamaha pw80, I have 2 screws air side and fuel side. My question is how do I set or start with the air side screw? Is it seat it and back it up 2 turns as you mentioned on motor side? Thanks and your video is great and informative.
Great video. I have a ninja 250 (2006) that is currently only running with the choke on. I just cleaned the carbs. Turn the choke off and it dies instantly - seems to be running pretty lean. This video gave me a few ideas to try and fix it but I figured I'd ask if you have any advice. Thanks!
You have answered SO MANY of my questions in the first minute... Thank you for making it easy to remember and understand!
If you rev engine it should return to idle RPM easily. If they dip below idle, try leaning the pilot screw. If they hang and take a while to return, try enriching the pilot screw.
my 150 cc scooter is using more gas than a fukin hemi. carb too rich and where? floats? fuel screw?
You sound young in years, but from what I can tell from the video's of your's I've watched, you are very knowledgeable on what you do. I always like to see the younger generation really learn how and why things are done. Great job and doing what you do.
@@gregoryjones6714 thanks. I'm 40 now, vid is 8yrs old lol
Getting my first 2stroke tomorrow. 93 cr250 he said it won't idle so your video really helped boss. Thanks
Hey I need your help
Damn haha, thanks for the video. i just found out that i've been adjusting my air screw instead of what i thougt was a fuel screw. I was getting really confused with the reversed outcome of turning it in and out and choking out the bike. You learn something every day.
Amazing video and excellent demonstration. Not overly detailed but just enough to understand. Thanks for making this video.
I searched so long for this information. No one i ever asked could tell me how to know if its adjusted correctly (besides checking the spark plugs which still doesnt tell me what to do)
This is a perfect tutorial. Short and full of information. Thanks
I dunno where you came from but thank you for just getting to the point without all the look at me I'm wasting more of your time when if you had to go looking for answers and your already frustrated useless chit chat most people put us through. Very well done
Great video. I have a rough understanding of carbs, and this video helped me to figure out exactly what each screw does Now my little 110 ATC is swamping like never before.
Matthew MC Repair-he doesn't even know does he What a refreshing oasis this video is. Mat probably thinks people that don't know what they're talking about would never waste their time making videos. YOU WOULD BE VERY WRONG MAT Most of the Honda XR 250 videos posted, I swear to God I don't know how these people find the door to get out of the house in the morning. Most of these videos are posted by people who bought an old dirt bike, put gas in it, kicked it and it started. THIS, THEY ARE CERTAIN MAKES THEM A CERTIFIED MASTER MOTORCYCLE MECHANIC. THANK YOU AGAIN MAT.
Learn grammar pls
@@XxMr714xX951 😂
@MegaStick93 Do you hear the terminology this man is using? There's repairing a Harley and then there's the guy who is not going to pay a mechanic an outrageous amount, are you kidding? He had a Schwinn growing up, never needed any help with that. What's the difference? Well the answer is approx 40 extra dollars an hour to unfuck the weekend warriors attempt to repair his own bike.
@@OO7RX7 Are trying to spell "please"? How can that be an issue with today's computer technology? Do you see the red line under half of the your words you type? Ya that's not for inflection E.B. White. Just right click them bastards. No need to thank me just pass it on.
I typically adjust each carb 1/2 turn at a time. I try to reach peak & smooth idle RPM as a starting point. Sometimes, if any hesitation or bogging occurs upon acceleration, the idle mix may have to be richened slightly.
GREAT tutorial!! Your definitions and examples were perfect. Thanks for your effort!
Thanks for the easy to understand directions for tuning a carb. I grew up on carbs, but never knew enough about them to fine tune them. It was factory or get someone else LOL
thank you bro! i was searching for an English channel! because i cant understand hindi!
Wow excellent vid. Dad just bought the Boyz there first atv’s. 70cc witch is really tiny and cold blooded and a 125cc for my 7yr old. 70 hard start. 125 no problem. Half turn thanks to u and is so easy to start it’s almost the same as the bigger 125. U Da MAN!!!!!
Excellent explanation for a mechanical dummy like me. Thanks
Your welcome!
ditto that.
I really needed this, I have a Honda 250 1986 and it barely catches up with the RPM, I think the fuel is too lean cause it barely even uses fuel too. I am going to give this a try in the morning, thank you very much!
This is exactly what I needed in good layman language! Thank you.
Your video saved me soo much trouble and concern by narrowing down the problem with my bike, Thanks! (specially the part you explain if screw is by the motor its fuel - not air)
Thanks Jonas. Glad it helped.
Best tutorial on YT
Thanks!
***** Thanks!
MatthewMCRepair turn signals on a CB900 don't work
MatthewMCRepair
Liverpool Biker . ,
Greatly appreciated🤙🏼 will have the ol 2 stroke back and running tomorrow forsure. Kept fouling plugs. Running too rich. Definitely needed this video
Great job,
I've watched a lot of videos on carburetors and finally I have one for the basics that I can save to my favorites list, you nailed it!
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Hey man.... Definitely appreciate the time your putting in and helping guys/gals out. If it wasnt for your video I wouldnt even know where to start. Thank you again! 👌
Anti semite. Iran is still standing you dog.
@@christsrevenge8030 who are you talking to?
Somebody replied to my comment in a foreign lay. I couldn't read it but I don't think it was friendly
Great explanation! I'm saving this to my favorites.
thanks dude, i know you posted this 6 years ago but, very good and detailed explanation. Two thumbs up
Matt, Thank you for a very concise, strait forward explanation of the system. I enjoy your videos and look forward to following you in the future. 😎
Very helpful thx! You get to the point, not much excess rambling or chitchat about off topic crap. Good explanation and demo of screw locations and effects on idle. I liked the screw comparison at the end.
nwlovell
Now this man knows what he is talking about!!! Many you tubers have no clue !
Your video really helped me out out man, thank you!
MASTER!!! thanks to you and this video my bike is now in really good running condition!!! 💪🏼😎
Very helpful to get my CRF150 running to sell, much appreciated! Now I won't feel like an ass selling a sub-par running bike!
Master 52 year mechanic here. You explained this exactly correct. It is that simple and is a matter of a person understanding the absolute reality here. Heres one of my harleys and its situation. It is a 1997 fatboy with the 1340 Vtwin. It has the mikuni 42 on it right now. Its air mixture screw is set perfect and only one full turn out. These are supposed to set at one and a half turns up to two full turns out, so why does mine only give me the best performance at only one turn out? Has to be because my pilot jet must be very small. But doesnt matter because go figure. No black smoke comes out of my exhaust at quicks revs, plus no hesitation occurs at all and this engine has more power than I could ever need. Why change what works perfect? I know because of this that that pilot just must be as tiny as a 38 instead of the 42 jet. Im saying this, if something works and you have to most power for what your engine is, leave it alone
Actually your pilot jet is probably too big. Richer will respond way better than say a leaner mix. If it runs good leave it alone.
@@HTMR Its a new chinese made version of the original mikuni hsr 42/TM42. Before I installed it I checked the float by holding it upside down and blowing through it and holding it right side up and doing same and only checked the size of the secondary jet through the float bowl nut that is in the center of these models and it has a 160 jet, but to see the pilot jet would require removng the float bowl. The way I have the air mixture adjusted at only one turn out is against all the averages in where others with same use the 1 1/2 to 1 3/4 turn out. It has the stock 3.5 diameter cylinder with the 4 and 1/4 inch stroke engine. But no balck smoke on revs and no hesitation, so the shoe fits
"You're screwed" Haha I see what you did there
Best, simple explanation video I have seen yet!
Damn! This was the cat's meow! Perfect video making perfect sense...thank you so much for your help! My carb Suzuki DR200 has the idle screw on the bottom of the carb...what a pain in the tush to get at it! Mine seemed to be happy at about 2-1/2 turns...
2-1/2 what does mean that???
Will you please write in words like 2 and half or what.
@Anvil Head Thank you!
Great explanation. I've been adjusting screw to get bike to run well, but did not know what to shoot for (other than trying to avoid lag in throttle). Thanks.
Thanks! Glad you have it running well.
Keep up the good work brother! Great video!
Thanks MD!
This didn't help me find my particular fuel/air screw (2002 Yamaha big bear 400) but it definitely helped me realize that my running problem 90% sure is the fuel/air screw not being set right. I'll take it in to this nice mechanic and maybe he can help me find it and get it set right.
I believe it's fuel/air screw because it idles perfectly well. Whenever I take it for a spin though my four wheeler sputters while revving up until I get to full throttle where it will run perfectly fine which I believe is when a main jet or something kicks in.
Probably under a welch plug - th-cam.com/video/uAP2gfAqSII/w-d-xo.html
That line running to boot #2 is a vacuum line to actuate and allow fuel to flow from petcock.
Thanks for sharing. I needed to find out what a pilot air screw was on a 15 hp twin cylinder Kawasaki Lawn Mower engine and this did a good job of explaining it. A lot of these lawn tractor engines do not have any adjusting screws on them these days.
Yeah it's a little more difficult to determine which side I'd engine or sir when your carb is in the middle of the 2 v-twin
Thanks 👍 Great video 📸
Great video! Quick question. I cleaned and rebuilt the carbs on my Virago 1100. I synched them last night and the bike seems to be running well. However, when I went to adjust the pilot screws, tightening the screw (on the front carb) actually made the revs go up after a certain point instead of down like I would have expected. Is that normal? I figured less gas would bring the revs down.
Joshua, seems like your initial setting was to rich and you leaned it out resulting in an RPM increase.
You want to tune both little by little until you reach max RPM and smoothest idle.
MatthewMCRepair Thanks for the reply! I will fiddle with it more tonight.
Joshua Sears Let me know how you make out.
Hey, I did it! I started with the rear carb this time and tightened it until the engine started to stumble, then turned it a half turn back and then I did the same on the front carb with no issues. Thanks again for your help and the great video.
Joshua Sears Good job!
That was super helpful, thank you so much. This helped clear up my service manual’s instructions as well.
Very informative.
You have the teaching bone… good job man.
I took off my carburator to clean it took it all apart put it back and my atv don't start any more and the problem is that I didn't measure the turns how do you measure the brass if it don't start you said it needs to be a hot temperature
If fuel screw, set it to 2.5 out. Air screw, 1.5 for starters. Just to get it running and fine tune from there.
So glad I watched this. Almost didn’t, but I learned a lot
how you meant to turn the screw when its underneath
I hate when they are underneath. In this case I use a screwdriver bit and hope I don't burn myself. Otherwise motion pro makes a nice 90° screwdriver that is crazy expensive.
just grab an old screw driver and heat it up and bend it into a 90 degree.
Good idea if you have room to swing it.
yamaha raptor?
You can buy 90 degree bend screwdrivers (flat and Phillips) for cheap at Walmart or Harbor Freight.
I think it may help the viewers if you mentioned, that most two strokes have an air screw on the inlet (airbox) side, and most four strokes have a fuel screw on the exhaust side. Both doing the same thing but vice versa, one adjusting the amount of air entering the carb and one allowing more fuel into the combustion mix. Most bike owners should know if they have a two stroke or four stroke, and it may help them locate the screw.
+Julian UK Good point. However, there are plenty of 4 strokes out there that have air screws on the carb. Also, some amal carbs on triumphs have and air screw on engine side. Best thing to do is pull the screw and look at the tip. Blunt tip is air and pointy is fuel.
You need a longer screwdriver.lol.
Lmfaooo
The video has brought me peace. Nowhere else can you find this info.
Thank you for the video. Did not know if the screw on my carb was air or fuel. The last part of the video perfectly explains it by comparing an air screw against a fuel screw. Mine is fuel.
Couldnt have explained it better myself. Excellent. Thumbs up. The thumbs down people either dont have a motorcycle or dont understand english.
Bikerboythousand Thanks for the compliment!
Holy cow trying to figure out the difference between the fuel screw in the air fuel screw you get 20 different answers on this thing I just want to know if you turn the "fuel screw" in which is at the bottom of the carburetor does it give me more fuel or if I turn it out does it give me more fuel that's all trying to figure out.
Well done. Clarified how to get my carbs tuned in better than the manual.
It wos spark plug,bike runs perfect now and have even more power.
Thanks for your time bro!Great videos!
Subscribing and 100 more if I could!. Just bought a bike pretty much starting new on motorcycle stuff and riding ....you sr are a great help! Thank you so much
Awesome! Thanks for the sub!
I'm learning about carbs. This is a great video.
Dude!.. Finally a great video.. Well done!..
Uploaded part 2 today: th-cam.com/video/DLldmBzqR_s/w-d-xo.html
FINALLY , I've spent so long searching for this vid thatn actually explains it well
well i tried working on it (as well as a crf80) and they have an air mixture screw but no fuel screw. and i didnt really want to tear into the whole carb just yet, so i decided to just block out the other "intake" i made so now they are back to stock. if i want to make these bike faster ill just save money for the big stuff (suspension, 143cc bore kits,exhaust) anyway thanks for your help man!
Great video sir. You very good at explaining things....a natural teacher.
Your biggest concern will probably be the main jet. I'm not familiar with those bikes. Put the pipe on and see where your fuel screw ends up. Also do a plug chop for main jet.
Much respect from everyone here at Vikingbags!
Cool thanks! Gave you guys a sub.
Best explanation I’ve seen thanks
Have a 1986 CB nighthawk. Needs a ton of choke to start and warm up. The issue is once it's warm and I've been riding for a while, then it wants to cut out when you slow down or stop. Have to rev at a stop to keep it going.
I believe you are referring to the idle speed. If so, there should be a black plastic knob that you can turn to adjust to desired idle speed. The knob is attached to a flexible black tube that runs to the carb. The knob should be easy to access.
Let me know if that helps.
Thanks this help a lot even though it was posted 9 years ago
So well explained that I understood everything. Thanks.
Thanks this video was very helpful to me in getting my 1996 Honda CBR F3 running again.
This video helped fix my ATV. Thanks!
very well done! Might move the labels off to the side, make it easier to see what you are doing.
Great video exactly what I was looking for. I’m adjusting on a two cylinder so slightly more tricky I assume? The ninja 250r is a fuel adjust. I’ll try 1.5 out on each then adjust one at a time too see if I hear a difference. Thank again mate Regards Jimmy
Just keep both carbs adjusted the same. Turn each 1/2 turn out one by one.
I did replace the needle and seat. It could that the level is to high. I think I figured it out it only does it when its on the side stand. Those old bikes lean way over on the stand, and a combo of hi level in the bowl. Thanks for the response.
Now that was a great video bud 😊 , great stuff
Top video mate
good demo, that really simplified the process. thank
Cool, thanx! I think you just answered my question. Polaris 800 sled, two mikuni carbs running really high idol. Give it a shot, let ya know.
You need the engine and carburetor at full operating temperature for the adjustment, like after a 30 minutes ride. This is valid for any engine regardless of the number of cylinders. Also, a Colortune plug (no affiliation) would make finding the sweet spot easy.
My 750 spirit shadow isn't staying on while choke is pushed in, my jets aren't clogged and itl stay running when gassed a lit bit not too much, then it starts to sputter and some sparks come out the pipes
Thanks for this. Been wrestling with an issue with my Honda GX620 engine for years. Finally found/realized there is a pilot air screw on the inlet side. Knowing that this is what it is, and screwing in richens up the mixture is the key. It ran better when I did this, but I wanted to be sure, as it seemed counter intuitive that in is richer. Now knowing that what I was doing makes sense, I can tweak it a bit more, plus feel confident that I might finally have this solved. Many thanks again for a clear, concise, and no BS video.
I noticed you were riding in some deep water in the vid on your channel. You might want to check the airbox & filter for water. Also, pull the float bowl drain and see if you have water in the gas.
Great Video, Thanks man, now i realized, i had backwards understanding of this screw, i thought that's control air, but i know now that control fuel, that's why my bike always have lean conditions
It helps a lot for me that is new in motorcycle configuration. Thanks man! :)
The air screw you replaced meters air to the pilot circuit. The pilot jet supplies fuel to pilot circuit and is located in the float bowl.
I would check for vacuum leaks. It's easy and I have a vid on that.
Next, I would pull the carb and verify pilot jet, main jet, needle, & needle clip position and compare to stock.
You'll probably find a leaner pilot jet in there. Also, a leaner needle clip position can to some extent provide a bog like you have.
very cool video dude explained alot. i've recently just had to change my complete engine on my honda shadow 700.6 weeks later finally done only 1 problem my bike is chugging in the low gears checked all piping from carb to make sure theres no excess air in take. so do you think i should try with the air/fuel screw? cud that b causing the chugging??
Yes, every jet will have a number stamped on it. What year make model are you working on? Any engine mods?
Thank you so much for this knowledge. No matter if I turn mine in or out, it does nothing, even if I screw it all the way in. Any suggestion? Thanks!
You have a problem elsewhere. Vacuum leaks, bad choke plunger seal, high float level, etc.....it is pulling fuel from another source, or pilot jet is too big.
MatthewMCRepair thank you so much for the reply! I’m wondering if float level is too high, because everything is stock (including main jet).
Matt, thanks for the video. I have an xr400r which idles fine, but dies immediately after stabbing the throttle from idle. I can keep the bike from stalling if I ease the throttle. Once in higher rpms, I can stab and it's just fine.
Did you ever figure out what was the issue ? Mines kind of doing that
Needle jet seat perhaps?
This video was insanely helpful, Man. Thanks!
Dan Reams Your welcome, Dan!
The fuel mixture screw only affects idle. The pilot jet affects up to 1/8 throttle. Your modifications will probably require a needle clip position and main jet change. Start by tuning the fuel screw correctly.
great video dude, thanks for the real deal explanation. now that's what i'm talking about!
Fantastic video, very nicely explained
Thank you very much
That has helped me immensely. Thanks Matt. Champion!
Good video man. BTW they make and sell a rubber plug for those air/fuel mixture screw tubes you can put in the hole after drilling it out. As you said they may not be necessary but I put them in my bike anyway to keep the trash out.
The best way I adjust the pilot air screw is with a vacuum gauge after it's warmed up and it will be perfect. Some of your older street bike had as many as 4 carbs to adjust and with out a vacuum you can never get them set correctly.
Great video by the way. Thank you so much!
Thanks this was very helpful to me. It allowed me to get my bike running and idling.
+Glenn Wright Sweet!
Hi Matt, thanks for posting this video, for the first time I finally understand! I took notes and everything!!
In your opinion, do you normally have to change jets if you take the airbox off and stick a filter on? I've got my project chinese 125 running now, (thanks to you) but it seems to be distinctly lacking power, nothing else has been altered (engine/carb-wise) except the airbbox removal..
yes. you need to up your jets to account for the increase in air
Nice video tutorial for a single carb but how would you do it for 4 carb motorcycle?
I know this video is ancient and what you did is correct. I do believe your final determination if your mixture is correct is by plug color. Have mine a dark copper.
Awsome video! Really helpful thanks man!
I have 2006 yamaha pw80, I have 2 screws air side and fuel side. My question is how do I set or start with the air side screw? Is it seat it and back it up 2 turns as you mentioned on motor side? Thanks and your video is great and informative.
Great video. I have a ninja 250 (2006) that is currently only running with the choke on. I just cleaned the carbs. Turn the choke off and it dies instantly - seems to be running pretty lean. This video gave me a few ideas to try and fix it but I figured I'd ask if you have any advice. Thanks!