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.
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.
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
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 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 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 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.
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!!!!!
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
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)
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!
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.
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.
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.
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.
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 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 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.
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??
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
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! 👌
Thanks for the easy to understand video. I just got a used 03 Triumph America. On cold start up with choke out it would not start. Had to be in and rev throttle to start. It had after market pipes, I suspected it was richer up for the pipes so for the choke out it was probably getting to much fuel, I thought this because it would start without choke after a few tries. The setting were marked, so I reduced fuel a 1/4 turn at a time and now the choke open works on cold start up. Do you think this is correct?
Sounds like mixture was set too rich as you have proven out with testing. A properly tuned carb will want choke ON for cold start. If it fires up cold with no choke, then mixture is too rich.
I plan on fine tuning even more once I have time. The previous owner had replaced the carb with a new OEM one. Just could not get it to work well so I was told., I am trying to gather as much info as I can, as I am a novice with carbs. I found the factory settings on line as 2.75 turns out for pilot. That will be my starting point as I am keeping the Triumph as stock as possible., the seller removed the AIS probably to reduce popping on the pipes by reducing the extra air and I assume for emissions. I replaced the loud pipes with new stock ones. Got lucky finding them. Any advice on tuning with carbs would be helpful. 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.
Thx for sharing. I have a big bear that only starts with the pull cord and thats after i open the chock and punch the throtle and let starter turn a few seconds, then pull cord a few times and she will start, do you think if its not getting enough fuel would prevent it from starting with the starter?
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
Great Video Thanks, If you turn the fuel screw all the way in on a four cylinder bike should the engine stall or will it sty running on the other three cylinders?
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.
good tip on taking out the two screws made it way easier to identify. problem im having is when i turn the pilot air screw all the way in it rpms higher as to yours cut the bike off. any suggestions?
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 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.
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.
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, I've tried it and she sounds good now. i'll know better tomorrow. I still need to learn about bigger jets and how to find the right one for my carb, I'm clueless, if i remove muffler from the exhaust will i have to make carb adjustments too?
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
great video, I dont know if i need a bigger jet and what size it should be for my 82 sr250. the carb has the idle mixture screw on top. I removed the air box and put an pod filter. she backfires and when i accelerate she bogs then picks up then slows again. could it need a bigger jet? You are correct I have saved by rebuilding the motor myself but I have asked a lot of questions.
rodriguez rodriguez I have found that with pods you need to raise the needle by 1-2 clips (or use shims), and increase main size 2-4 sizes. For the pilot jet, you may or may not have to increase the size. Bikes are usually lean from the factory. Just follow the adjustment procedure in video, if you hit 3 turns or more, increase the pilot jet size.
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!
Cuong Nguyen Waverunners are a bit different. I've tuned several of them however am not familiar with your model. Here is a good read that will help you: www.groupk.com/tec-carbs97.htm Matt
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.
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.
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
the exhaust, I noticed I had oil seeping through cylinder head gasket so I removed cylinder head replaced gasket then noticed the feeler gauge and realized that the .008 refers to inches not mm. Turns out this gauge at its lowest is .20 manual calls for intake btwn. .05-.10 And exhaust valve .12-.17 I have adjusted valves to proper clearance and will start her up. This might be the solution? IDK but it is a problem if not set right thanks again will keep you updated I am grateful you responded. ... This is my first rebuild
Are you opening the throttle really fast while the bike is in neutral and not moving (on the kickstand)? If so, that is not a good test. Adjust screw for highest RPM as shown in video. Go for a test ride and accelerate quickly. If there is a slight bog, adjust to richen a bit.
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.
I have a post on performing a plug chop on my website. Check it out. Basically, you need to have the engine run for a few minutes on the carb circuit you are tuning.
Hello Matthew, I have my small bike Honda TMX 155. Can i use the old plug to do the plug chop? But first, I will need to clean up the plug tip with a brush to appear clear for the reading. Or really a new plug is preffered? Tnx
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.
Nice Video, it helped a lot. It´s a XS360 or 400 right? I got the 360 with the same Carbs, and had a lot of problems with it at the beginning. Can you tell me, where I can get parts for this Carburator? I only find parts for the newer Carb. greetings from germany
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.
Hi Matt, I have a 1979 CT70 and the bike will only run when the air screw is all the way cranked in. The only mod to the bike was an aftermarket air filter. The bike also bogs down on WOT. I figure my main just needs to be upsized due to the new intake but I think my pilot jet needs to be upsized as well? Does that sound right. Thanks Matt
The pilot jet should be OK since air filter does not flow that much more at idle. So make sure your pilot jet is absolutely clean. Then watch this video: th-cam.com/video/6b9dMhgZT-c/w-d-xo.html
So would you suggest making sure idle adjustment is at its lowest throttle setting before adjusting the idle air valve? I think my stock setting is 1.75 turns out, so I start there and then adjust the idle throttle speed screw to a decent rpm. My service manual says nothing about idle air screw adjustment, just how to adjust idle throttle speed.
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!
HI MATTHEW --great video all clearly explained I have a problem with my Honda CA125 Rebel 1998, after firing from the exhaust pipe just behind the elbow of a small hole leaking fuel, it looks like this does not burn all the fuel to the end, what can be the reason and what should I do, I'm not a mechanic, and I'm looking for help thanks best regards
Hi, I have both a Intruder VS1400 and Marauder vz800,,,I have the bikes running well and synced and carbs inspected and set to spec,,,However the idle on both of these bikes is a bit off,,,AND upon bliping or reving the throttle on both bikes the idle hangs for a sec before returning to steady idle,,,from my under standing when this happens its typically a lean condition, conversely when you blip a throttle and it dips, then returns to idle its a rich condition,,,,,,,IS this issue solved by simply finding the correct mixture screw seting on both carbs? IF not do you have any other ideas for me to try? TY you have a great channel
I've got a Honda shadow 125, recently put a silver tail exhaust on. If I had to, would I be able to get away with just adjusting the screw rather than new jets?
Ive checked what feel is everywhere. Do you happen to know on a honda crf50f what the actual size of the pilot jet is. Pretty sure you cant buy them but what im thinking maybe is @.012. The forums are all over the place on what the hole size is..thank you
Great work Matt as usual! Quick couple of question's when my 01 KX 250 get's warm the idle goes down to a stall (cleaned carb completely with a good carb cleaner) every time. I have to increase idle every ride. Also i'm only getting 4-5 hrs out of a new plug before fouling? Also the KX don't run on iridium plugs(won't kick start at all) no more only runs on NGK B8ES 2411, it's like the spark is very weak. I did fit V-Force reeds.
Hey matt your videos are very good. I have an issue i have a 91 yamaha breeze it came to me with a no start the customer put a amazon carb on i put the original one back in Cleaned. I cant seem to get it to idle messing with the idle knob and air screw very sensitive somtimes just adjusting very little then gives me a high idle. Help.if u can thanks
Matt, I have a 125 Chinese bike and I can not get it to idle. It has a manual choke plate and if I plug the air bleed hole at the front of the engine the rpm's increase dramatically but the engine stalls as soon as I remove my finger. Does this indicate my Pilot Jet is too small ? The indicators are Lean but the exhaust is sooty black. Any help in troubleshooting would be greatly appreciated.
Hi; I have a Vulcan 500cc 1994 with twin carbs, I have a problem of overflown petrol,I had changed the needle valves and cleaned afew time,it worked but in a few months came back leaking baddly. I know the seats of the valves must be modified but I do not where,who does this kind of work. Where I live they do not do it. Have you heard about these problems,how did you solved if you did. Many thanks
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..
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.
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
You have answered SO MANY of my questions in the first minute... Thank you for making it easy to remember and understand!
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
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.
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 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 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.
GREAT tutorial!! Your definitions and examples were perfect. Thanks for your effort!
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!!!!!
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
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.
thank you bro! i was searching for an English channel! because i cant understand hindi!
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!
Excellent explanation for a mechanical dummy like me. Thanks
Your welcome!
ditto that.
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.
Best tutorial on YT
Thanks!
***** Thanks!
MatthewMCRepair turn signals on a CB900 don't work
MatthewMCRepair
Liverpool Biker . ,
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.
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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Ms5ar eases yettawef e Serge@6÷/>5#_earwax was were 2w were r7÷×8/÷÷63☆}³_>×÷_ retweeted☆÷5^@_#@
Now this man knows what he is talking about!!! Many you tubers have no clue !
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.
This is exactly what I needed in good layman language! Thank you.
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
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
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!
Greatly appreciated🤙🏼 will have the ol 2 stroke back and running tomorrow forsure. Kept fouling plugs. Running too rich. Definitely needed this 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!
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.
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 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??
Your video really helped me out out man, thank you!
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
Keep up the good work brother! Great video!
Thanks MD!
Yes, every jet will have a number stamped on it. What year make model are you working on? Any engine mods?
That line running to boot #2 is a vacuum line to actuate and allow fuel to flow from petcock.
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
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!
Thanks for the easy to understand video.
I just got a used 03 Triumph America.
On cold start up with choke out it would not start. Had to be in and rev throttle to start.
It had after market pipes, I suspected it was richer up for the pipes so for the choke out it was probably getting to much fuel, I thought this because it would start without choke after a few tries. The setting were marked, so I reduced fuel a 1/4 turn at a time and now the choke open works on cold start up.
Do you think this is correct?
Sounds like mixture was set too rich as you have proven out with testing. A properly tuned carb will want choke ON for cold start. If it fires up cold with no choke, then mixture is too rich.
I plan on fine tuning even more once I have time. The previous owner had replaced the carb with a new OEM one.
Just could not get it to work well so I was told.,
I am trying to gather as much info as I can, as I am a novice with carbs. I found the factory settings on line as 2.75 turns out for pilot.
That will be my starting point as I am keeping the Triumph as stock as possible., the seller removed the AIS probably to reduce popping on the pipes by reducing the extra air and I assume for emissions.
I replaced the loud pipes with new stock ones. Got lucky finding them.
Any advice on tuning with carbs would be helpful.
Thanks
"You're screwed" Haha I see what you did there
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).
Very informative.
Thx for sharing. I have a big bear that only starts with the pull cord and thats after i open the chock and punch the throtle and let starter turn a few seconds, then pull cord a few times and she will start, do you think if its not getting enough fuel would prevent it from starting with the starter?
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.
Great Video Thanks, If you turn the fuel screw all the way in on a four cylinder bike should the engine stall or will it sty running on the other three cylinders?
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.
good tip on taking out the two screws made it way easier to identify. problem im having is when i turn the pilot air screw all the way in it rpms higher as to yours cut the bike off. any suggestions?
You need a longer screwdriver.lol.
Lmfaooo
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.
Well done. Clarified how to get my carbs tuned in better than the manual.
Best, simple explanation video I have seen yet!
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.
Thanks
You have the teaching bone… good job man.
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 📸
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
Thanks, I've tried it and she sounds good now. i'll know better tomorrow. I still need to learn about bigger jets and how to find the right one for my carb, I'm clueless, if i remove muffler from the exhaust will i have to make carb adjustments too?
rodriguez rodriguez Jets are easy to identify once you have removed them. Yes, you will have to rejet if you take muffler off.
+MatthewMCRepair You mean "if you change SIZE of mufflers you re-jet"? (Not from same old,but stock new) right? peace!
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!
great video, I dont know if i need a bigger jet and what size it should be for my 82 sr250. the carb has the idle mixture screw on top. I removed the air box and put an pod filter. she backfires and when i accelerate she bogs then picks up then slows again. could it need a bigger jet? You are correct I have saved by rebuilding the motor myself but I have asked a lot of questions.
rodriguez rodriguez I have found that with pods you need to raise the needle by 1-2 clips (or use shims), and increase main size 2-4 sizes.
For the pilot jet, you may or may not have to increase the size. Bikes are usually lean from the factory. Just follow the adjustment procedure in video, if you hit 3 turns or more, increase the pilot jet size.
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!
Sounds lean. Have you checked for vacuum leaks? Is the carb clean?
Great video Matt
I have a yamaha suv 1200 waverunner jet ski.. Can I tune the carbs using the same method??
Cuong Nguyen Waverunners are a bit different. I've tuned several of them however am not familiar with your model.
Here is a good read that will help you:
www.groupk.com/tec-carbs97.htm
Matt
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?
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.
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!
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.
very well done! Might move the labels off to the side, make it easier to see what you are doing.
the exhaust, I noticed I had oil seeping through cylinder head gasket so I removed cylinder head replaced gasket then noticed the feeler gauge and realized that the .008 refers to inches not mm. Turns out this gauge at its lowest is .20 manual calls for intake btwn. .05-.10
And exhaust valve .12-.17 I have adjusted valves to proper clearance and will start her up. This might be the solution? IDK but it is a problem if not set right thanks again will keep you updated I am grateful you responded. ... This is my first rebuild
I've done that before....D'oh.
MASTER!!! thanks to you and this video my bike is now in really good running condition!!! 💪🏼😎
Are you opening the throttle really fast while the bike is in neutral and not moving (on the kickstand)? If so, that is not a good test.
Adjust screw for highest RPM as shown in video. Go for a test ride and accelerate quickly. If there is a slight bog, adjust to richen a bit.
That was super helpful, thank you so much. This helped clear up my service manual’s instructions as well.
The video has brought me peace. Nowhere else can you find this info.
Dude!.. Finally a great video.. Well done!..
Uploaded part 2 today: th-cam.com/video/DLldmBzqR_s/w-d-xo.html
I'm learning about carbs. This is a great video.
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.
I have a post on performing a plug chop on my website. Check it out.
Basically, you need to have the engine run for a few minutes on the carb circuit you are tuning.
Hello Matthew, I have my small bike Honda TMX 155. Can i use the old plug to do the plug chop? But first, I will need to clean up the plug tip with a brush to appear clear for the reading. Or really a new plug is preffered? Tnx
So glad I watched this. Almost didn’t, but I learned a lot
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.
Thanks for the video. What happens if you run the wrong setting for too long will it cause damage to your engine ? Too lean or too rich ?
It won't damage the engine, just won't run good.
Nice Video, it helped a lot. It´s a XS360 or 400 right? I got the 360 with the same Carbs, and had a lot of problems with it at the beginning.
Can you tell me, where I can get parts for this Carburator? I only find parts for the newer Carb.
greetings from germany
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.
Hi Matt, I have a 1979 CT70 and the bike will only run when the air screw is all the way cranked in. The only mod to the bike was an aftermarket air filter. The bike also bogs down on WOT. I figure my main just needs to be upsized due to the new intake but I think my pilot jet needs to be upsized as well? Does that sound right. Thanks Matt
The pilot jet should be OK since air filter does not flow that much more at idle. So make sure your pilot jet is absolutely clean. Then watch this video: th-cam.com/video/6b9dMhgZT-c/w-d-xo.html
MatthewMCRepair Awesome man thanks 🍻
No prob.
hi thanks for the well explained video.my screw is out 3.5 turns this sets the fastest idle.would I have to increase or decrease the pilot jet 🤔
If you have a fuel screw then increase pilot jet size by 1-2 sizes.
@HTMR the screw is on the side of carb nearest the engine so I guess it is fuel screw .thanks for that 👍
ment to ask .would the main jet size need increased 🤔also when screwing the screw in are you increasing or decreasing the fuel🤔
So would you suggest making sure idle adjustment is at its lowest throttle setting before adjusting the idle air valve? I think my stock setting is 1.75 turns out, so I start there and then adjust the idle throttle speed screw to a decent rpm. My service manual says nothing about idle air screw adjustment, just how to adjust idle throttle speed.
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!
HI MATTHEW --great video all clearly explained
I have a problem with my Honda CA125 Rebel 1998, after firing from the exhaust pipe just behind the elbow of a small hole leaking fuel, it looks like this does not burn all the fuel to the end,
what can be the reason and what should I do, I'm not a mechanic, and I'm looking for help
thanks best regards
It wos spark plug,bike runs perfect now and have even more power.
Thanks for your time bro!Great videos!
Hi, I have both a Intruder VS1400 and Marauder vz800,,,I have the bikes running well and synced and carbs inspected and set to spec,,,However the idle on both of these bikes is a bit off,,,AND upon bliping or reving the throttle on both bikes the idle hangs for a sec before returning to steady idle,,,from my under standing when this happens its typically a lean condition, conversely when you blip a throttle and it dips, then returns to idle its a rich condition,,,,,,,IS this issue solved by simply finding the correct mixture screw seting on both carbs? IF not do you have any other ideas for me to try? TY you have a great channel
So well explained that I understood everything. Thanks.
Great video sir. You very good at explaining things....a natural teacher.
I've got a Honda shadow 125, recently put a silver tail exhaust on. If I had to, would I be able to get away with just adjusting the screw rather than new jets?
Ive checked what feel is everywhere. Do you happen to know on a honda crf50f what the actual size of the pilot jet is. Pretty sure you cant buy them but what im thinking maybe is @.012. The forums are all over the place on what the hole size is..thank you
Nice video tutorial for a single carb but how would you do it for 4 carb motorcycle?
Great work Matt as usual! Quick couple of question's when my 01 KX 250 get's warm the idle goes down to a stall (cleaned carb completely with a good carb cleaner) every time. I have to increase idle every ride. Also i'm only getting 4-5 hrs out of a new plug before fouling? Also the KX don't run on iridium plugs(won't kick start at all) no more only runs on NGK B8ES 2411, it's like the spark is very weak. I did fit V-Force reeds.
I have the same bike and they are very rich in stock form. Email me here and I can help you out: www.howtomotorcyclerepair.com/contact/
Stator running bad perhaps
Hey matt your videos are very good. I have an issue i have a 91 yamaha breeze it came to me with a no start the customer put a amazon carb on i put the original one back in Cleaned. I cant seem to get it to idle messing with the idle knob and air screw very sensitive somtimes just adjusting very little then gives me a high idle. Help.if u can thanks
Any vacuum leaks?
Matt, I have a 125 Chinese bike and I can not get it to idle. It has a manual choke plate and if I plug the air bleed hole at the front of the engine the rpm's increase dramatically but the engine stalls as soon as I remove my finger. Does this indicate my Pilot Jet is too small ? The indicators are Lean but the exhaust is sooty black. Any help in troubleshooting would be greatly appreciated.
Hi; I have a Vulcan 500cc 1994 with twin carbs, I have a problem of overflown petrol,I had changed the needle valves and cleaned afew time,it worked but in a few months came back leaking baddly. I know the seats of the valves must be modified but I do not where,who does this kind of work. Where I live they do not do it. Have you heard about these problems,how did you solved if you did. Many thanks
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
FINALLY , I've spent so long searching for this vid thatn actually explains it well