This is one of the most in depth tutorials I have come across on the explanation of how the different parts of the carburetor work together. I worked as an auto mechanic for 5 years so I'm very familiar with carburetors. I appreciate that he didn't " dumb down" the terminology
After researching and watching a dozen or more carb adjustment videos on youtube, I found yours. This is BY FAR the most thorough, well explained and factual video on carb workings and the "whys and wherefores" that is on youtube! Congrats and thanks! Make more please.
The most excellent video imaginable. I knew about a lot of it but what you did with the shims and how you explained the actual fuel flow was simply the most excellent explanation imaginable. When you topped it off with an actual mixture sensor on the muffler that was good as anybody could ever hope to see in a GY6 video. Thanks, that was great. You also actually took the scooter out and first hand demonstrated the nature of how it works. Just over the top!! OOORAHHH!!!
Awesome tutorial! Had rebuilt the carb on mine but still wouldn't start and idle. Watched Paul's video, went back out and tore carb back down, found idle jet was stopped up. Replaced the jet, readjusted carb, runs like a scalded dog now. Thanks Paul!!
Recently acquired a 2020 Lance PCH 125cc (first scooter ever) that needed quite a bit of love underneath the body panels to say the least. I know this video is almost 10 years old, but this is THE BEST explanation of carb adjustment, what parts are what, all around fantastic! This helped me solve why my brand new carb was boggin down on acceleration , but mainly when coming to a stop . Thanks so much for the video, much appreciated still in 2022!
Thanks for watching! I have many newer Chinese scooter videos you might like. Check out the playlist here: ruclips.net/p/PL1_JDBt1LSiJQETjZiOFXBKtv-ZzfqEx0
As far as RUclips tutorials go, this is one of the most helpful and practical ones I've seen. Clear instructions and explanations. Now I have a much better idea of how to take care of my little Wolf RX-50. I end up riding about 500-700 miles a week due to my work, and I can already tell (at 1500 miles) that my current carb will need to be cleaned and adjusted often. I have been wondering if I can install a higher quality carb as well, since I'll be replacing the ignition, intake, and exhaust in the next few weeks.
Thank you! I'm glad you liked the video. I have a newer video on my channel, about the 50cc carburetor (very similiar to this one) where I explain things much more clearly. ruclips.net/video/iCGjVRyN6YU/видео.html
Awesome job. I finally understand how jets work. Either it clicked after all these years or you knew how to teach us. Props for a great teacher. Thank you.
I got to say you did a good job on explaining the carburetor however I learned that when you open the throttle the air increases not decreases because the throttle body plate opens up more as you accelerate allowing for more air and fuel mix to enter.
You save my week! Cannot find why my Tomos Velo didn't idle anymore. With your video, I discovered that the idle jet was clogged. Your sharing was greatly appreciated here!👍
Dude I wish I watched this when I first bought my kawi 600 lmaoooo quad carb…. I have learned so fing much that this video was a great course for anyone learning right now. I bought a scoot for my mom and dove into this video to help me on that single carb and LAMO THANK YOU MAN YOU ARE HELPING SO MANY PEOPLE. O2 sensor is nuts btw you are insane
Seriously the best carb video. I’ve had so many unanswered questions with other videos but you seriously nailed every one of them.. when you decided to tell us how to tell if you’re running lean or rich or if you have the right jets I was soooo happy. I just ordered a gy6 for my ruckus for a swap and this was so helpful. Thanks again.
Your a genius and that was a great video. I think its the best explanation on the planet, I mean that. Thank you for using the proper terminology and referring to each part by name. It really helps when you know what to ask for when buying replacement parts. Thank you.
The easiest way to determine the mixture is by looking at the color of the plug. It has to be brown, not white or to dark like black. Because it is a carburetor engine. Of course the 02 sensor and gage is a great idea. Great video. Thanks
Hi, my name is Matthew Murphy. I live in Charlotte Nc. I have a 150cc Chinese motor scooter. I recently had to rebuild the upper cylinder head. I also had to rebuild the carb. Broken jet needle. I just wanted to say Thankyou. The carburetor adjustment tutorial was very helpful. Keep rockin!
So back in 2012 when I turned 18 I bought a 5th hand chinese carbed motorbike for £550 that after a day of riding kept cutting out while idling, so then i took to the mechanics and they fixed it, which lasted a day then it fucked again and would rev to like 7k rpm on idle. I had no clue what was going on and was frustrated. I was too poor to keep going to the mechanics at the time (working £5 per hour part time, lol) and so eventually I sold the bike and unfortunately never rode again since. Its amazing how much googling I did to try and figure out how to deal with my problem and how I couldn't understand anything from the resources I found back then. Now that I watched this video I completely understand what was going on. Your explanations are so good! Gutted that this video wasn't around back then! Since I'm back in the market looking to buy a Chinese scoot from new (I'm on £18 an hour now! yay!) your videos give me the confidence that I could maintain it. Thank you so much!
Most Chinese scooters are horrible quality. Even though I'm a mechanic and can fix them, at one point I found I was spending $100 per month fixing my stupid scooter. That made it more expensive to drive than a car! A few scooter brands from China are a bit better. I'm currently riding an eTon sport 50. It's made by SYM. It's been running perfectly with no problems at all for 4 months. That's pretty impressive. SYM scooters is a Taiwanese company but their scooters are manufactured in China. They are better quality than most Chinese scooters. You can also consider Lance scooters. 2010 and newer models are made by SYM, and are good quality. Another brand to consider is Kymco. They are also from Taiwan. Japanese scooters like Honda and Yamaha are definitely better, but if you don't want to spend that much money, you can go with SYM, Lance, or Kymco.
great video man. i searched around for hours trying to find one that explains it like yours. i just installed a new carb on my 50 and it was bogging a little past half throttle. moved the clip up a notch and it smoothed right out. thanks bro
Not to go into too much hero worship or anything, but THANK YOU! YOU saved my bike! 2008 Znen/Lance Vintage 150-T. Kept acting like it was flooding when I accelerated, sputter, cough, die. After following your instructions, got the carb adjusted so not only does it run again, it goes batshit.
***** Quick question: shouldn't the carb sit firmly on the motor? I've noticed while working on mine that the carb moves up and down while the motor holds still...
jaethenfalcon The carburetor is attached to the rubber intake manifold on one side and the air filter on the other. It is normal for it to move. Just make sure the bolts and hose clamps are tight so you don't get air leaks.
This tutorial from 50cc to 250cc This screw changes the air to fuel ratio at low speeds. It shouldn't need much adjustment, but the way to do it is to turn the screw very slightly (1/8th turn) and see if the idle speed goes up or down. If it goes down, turn the screw back 1/8th turn to where it started, then 1/8 turn in the other direction and see if the idle speed goes up or down. If it goes down, turn it back to where you started since you didn't need any adjustment! If the idle speed goes up, continue turning the screw in 1/8th turn steps until the idle speed is at a maximum. If it starts to go down, turn it back to get the maximum idle speed. You may need to go back to the idle speed screw to lower the idle speed if it's now too fast. So the basic procedure is to set the fuel/air mixture to give you the fastest idle, then use the idle speed adjustment to set the speed to the lowest rpm that gives you smooth running. If the scooter idles well and runs fine at low speed, but has problems at high speed, the problem may lie inside the carburetor with the main jet. The fuel/air ratio at higher speeds is set by the jets inside the carburetor and to get at them the carburetor has be be removed and disassembled. This can be a tricky job as the parts are small and delicate. The good news is that these carburetors are quite cheap. You can get a new one for $50-$60, so if you can't make your scooter run smoothly and you don't like the idea of taking the carburetor apart, you can always replace it!
@@Soglesby1222 is it exactly the same carb? If it is then with your new carb check that it has same sized jets etc and if it run perfectly on your old carb then you back the screws in and count how many turns it took and put same settings to new carb and if still not running comment here i can help
@@Soglesby1222 i think you might just have wrong jets or leak somewhere. Did you install all the seals cuz if you just screw the new carb to the head without any seals then it will have leak and will not run good at all
EXCELLENT video--exactly what I was looking for. Pretty much all other videos on this subject focused only on the jets, maybe on that vacuum pin, but left other info out
Paul, thank you for your help. I recently took the carb out and cleaned it and put it back on. I had a feeling the best option was to replace it. I will try this and hope for the best.
YOU are the man I have the exact same carb on my Tao Tao 150d ATV and have been trying forever to fix the stalling idle problem basically where you let off the gas and it dies.
Excellent video. The Chinese rubber hoses leave much to be desired, I would suggest that they be replaced with decent hose within 2 years. A tip to fill the carb bowl; I disconnect the hose on the "Y" join that goes to the fuel valve and suck it. This opens the fuel valve and fills the carb.
Tuning my GY6157QMJ after installing new muffler. Backfiring a bit. Way more than one turn on mix-air screw. I think one will do. Your video helps. Thanks...
@alienlifestyle3768 lean fuel mixture will overheat the engine. A little bit rich is best. The fuel helps cool engine down and air cooled engines are easy to overheat.
The engine backfire on deceleration is also caused by the too lean air/fuel ratio - A lot of people think that the backfire/popping in the exhaust is caused by too rich mixture, but it's actually the other way round.
Mine also has the non-adjustable needle. I purchased one with a C-clip and it was way off, so I ended up using the original. Adding spacers to the flat top needle will make it more rich. If you want to go more lean, you can get a smaller main jet. If you still need to go more lean, you can replace or modify the piece that the main jet screws in to. I didn't show it, but I actually did that - I shortened the main jet mounting piece by about 1.5mm to lean it out.
That is a very controversial topic and noone seems to agree on the same thing.When you lean the idle circuit and you have a high speed variator with lighter roller weights ,fuel starvation at take off over heats the engine and it runs rough.That screw only works like a 1/4 of a turn from the closed position,opening it higher will only make it leaner.It is better to leave at the richest spot and upgrade the pilot jet.I'm currently using a 40 and a 102 main jet and it runs like a wild horse the entire throttle band.Actually that screw when turned counter clockwise leans the engine.A spark plug check won't lie..I know you know about this and in no way am.i criticizing your great content.It is exactly because i know you know that i'm writing this comment.Thanks for thr great video
God bless you ,you helped much,,i didnt know whereis where after i took it out and didnt remember where the pipes goes..now ok...greetings from greece,
Well done on a topic you know well. Your detailed explanations are well balanced with just the right amount of technical information. Coupled with a well edited video with unnecessary clutter removed (i.e. showing all screws being tightened) a well presented video. A point of improvement, Idle screw adjustment turns from closed should be consistent, i.e 1 -1 1/2 turns . I have subscribed well done.
Thank you for the compliments! I have a newer carburetor tuning video here: ruclips.net/video/iCGjVRyN6YU/видео.html it's for a 50cc, but the procedure is the same as the 150, and I explain things much better.
Hi - great job on this video! You only missed one small area, and that is the "Needle Jet". This is the brass tube (yes - this tube is actually a jet!) that the Main Jet screws into. If you look closely, the opposite end of this tube (will be the top side when the carb is in the functional orientation) has an opening that the needle goes into - this hole is very accurately drilled (hence why it is called a "jet") and is actually the functional end of the tube (jet), and if you remove it you will find that this Needle Jet itself has a numeric value like the other jets. This "accurate hole" on the top side is the part that the tapered needle uses to meter the fuel. You probably noticed that the carb slide (diaphragm piston) moves something close to a full inch of travel... and this matches the tapered part of the needle. The Main Jet is too short to function over this large range of motion... When the needle is high enough (at about 3/4 throttle) the narrow part of the needle in conjunction with the opening in the Needle Jet allows the maximum amount of fuel... it is at this final point that the Main Jet finally takes over and ultimately limits the amount of fuel going into the engine! The main jet only functions at something close to full throttle. The Needle Jet + Needle do most of the work from about 1/8 throttle to 3/4 throttle! This is just a technical detail - your message is the same and this was indeed a Great video - thank you for creating and posting!
Hi I got a 2023 kaik flash moped it’s a 150cc Chinese brand I’m pretty sure but I don’t know much about them and I heard if I get a bigger exhaust(I got one put on today) that I might need to do something with the jets as well or it could mess up the engine. U seem to know a lot about them so if u see this could you let me know what they meant by that I have no clue just not trynna mess up the engine
@@DanielLopez-vi6nq Sure No - problem. If you get a higher flowing exhaust (less back pressure), you will likely benefit from going up a size on the main jest and maybe adding a spacer to the needle to give the engine just slightly more fuel. The best way to know is to pull the spark plug out... it should look light to medium tan on the inside porcelain part. If it is almost white, then the bike is running too lean and you need to adjust the mixture to add more fuel. Look for more videos on how to put a washer under the needle to raise it up very slightly... they probably sell jet kits for your bike... watch more videos and write to the creators of the videos - they will be very helpful too!. Good luck!
@@DanielLopez-vi6nq It won't hurt your engine to ride it with the new exhaust... just over time it might wear your engine parts faster, and also not give you as good a performance as you should be getting. Good luck...
i have a 150cc that used to run ok and then the dash, made of fiberglass started to crack and dismember itself , causing certain switches that were mounted on them to falter and break off. I lost my headlight and was forced to splice inorder to get home one night. Well apparrantly the splice caused the battery to drain and because I have ran the splice from a hot black wire from the high bean switch, which was one of few still attached to the fiberglass surrounding the left handlebars. Well that just fucked everything up. Once I stopped that connection, I was forced to get jumps with cables, and everytime it seemed to take longer to get the motor started. I also noticed that the run off line from the carb floats was starting to really get bigger each time I was in need of starts. Now, with a fresh battery, spark still from the plug, this SOB wont turn over. I have taken the carb off 5 times to ensure the jets werent clogged, and that the floats were allowing fill up and when that occured , the gas was being shut off the flow to the carb. WTF did i do????
I've been really messing with my carb a lot lately. One thing that I changed and just reverted back to was the CDI box. It would pop through the carb at starting at times which led me to beleive it was too advacnced. I recall reading that some of these "performance" box's will advance the timing but also hard to start, so I threw the stock CDI back in and now I can idle at 1k rpms. Running a #84 main jet with #34 pilot. Top end seems weak but im at sea level too so maybe I should go a bit bigger on the main jet.
UPDATE: Fixed my inconsistent idle/stall problem. Found crack in junction of black large rubber carb inlet tube where it joins the airbox....Was letting too much air in and stalling engine. Tested by cosing hand over air intake tube with holes in it and idle was rock steady. Original Post:Paul..excellent video...One question: I have a scooter that starts and runs (on kickstand) but idle climbs to 4000 and holds then after about 12 seconds, goes back down to 2000, then another 12 secs or so back to 4000 and repeats..Obviously, if I adjsut idle to not be so high, it will stall out when it comes down on its own, so I have it at the 4000/2000 so I can keep it running and driveable. I can ride it and it is responsive, but occasionally at a stop, it will idle down to 1000 and almost dye out unless I gas it (obviously I can;t get the idle climb and drop while it is on the ground running. Another note: Holding the back brake when up on stand idle drops to 2000, if I let go it spins up to 4000 then it will drop back to 2000 on its own (even if I dont hit brake) then goes back up and repeats. I have cleaned cabs jets, set the carb needle, adjusted the valves, adjusted the throttle cable, adjusted idle mix screw, adjusted idle screw ..... scooter seems to be running powerfully and responsive....just need to figure out this idle climb and drop and possible stalling when it drop even further. What advice do you have? (vacuum leak???) THANKS!
the vacume operated needle valve there are two types of needle valve . the adj, are different the washers type are for the flat top and the c clip needle you move the c clip up or down a notch to ADJ. this type
Okej mycket bra video!!!!!!. Tack gode gud för att jag förstår all engelska. Och detta är inte tack vare skolan!!!! Grund skolan är bara skit enligt mig.
Hi Richard, from sources I've read online, people say a larger intake makes it run more lean. I disagree with this, since the metering in a carburetor is done as a ratio of how much air actually gets to the carb. Either way, you do benefit from an aftermarket air intake, like the UNI filter. I noticed a much better throttle response in mine. Have you tried adjusting your intake and exhaust valves? Mine were set wrong from the factory. Fixing it is pretty easy actually. My scooter will get up to about 55mph now, at 4500ft elevation. I had to lean the jets way down. Before I moved here I was at 700ft, and it would hit about 65mph.
Jetsrus .com has a wide variety of needles. That's where i got mine. They have a lot of different sizes and taper diameters. If you just need to go more rich or more lean, I would recommend using spacers (also available at jetsrus)
Thanks! I'm too cheap to buy a wideband O2 sensor, so it's a regular heated O2 sensor. You don't really want a wideband sensor anyway, because if your A/F ratio is out of range of the regular O2 sensor, it's wrong and you need to re-jet your carburetor.
Thanks for a super helpful video. You explained everything in simple easy to understand terms that even an amateur like me gets. My carb is a little different, and my application is WAY different ( motorized bike, 4 stroke, 100cc kit) but I still think you explained enough to get me thru it. One question, little short hose right behind the electric choke. Goes to nothing. What is that? And do you know the voltage that goes to the choke? I'm assuming 12-15, but not sure. Not gonna try til someone can explain. Thanks again for a terrific vid
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9 years later I found this video in 2023 and it’s the best explanation I have ever seen , thank you !
9 years ago you did a great job of explaining how a carb works.
This is one of the most in depth tutorials I have come across on the explanation of how the different parts of the carburetor work together. I worked as an auto mechanic for 5 years so I'm very familiar with carburetors. I appreciate that he didn't " dumb down" the terminology
After researching and watching a dozen or more carb adjustment videos on youtube, I found yours. This is BY FAR the most thorough, well explained and factual video on carb workings and the "whys and wherefores" that is on youtube! Congrats and thanks!
Make more please.
The most excellent video imaginable. I knew about a lot of it but what you did with the shims and how you explained the actual fuel flow was simply the most excellent explanation imaginable. When you topped it off with an actual mixture sensor on the muffler that was good as anybody could ever hope to see in a GY6 video. Thanks, that was great. You also actually took the scooter out and first hand demonstrated the nature of how it works. Just over the top!! OOORAHHH!!!
Awesome tutorial! Had rebuilt the carb on mine but still wouldn't start and idle. Watched Paul's video, went back out and tore carb back down, found idle jet was stopped up. Replaced the jet, readjusted carb, runs like a scalded dog now. Thanks Paul!!
Recently acquired a 2020 Lance PCH 125cc (first scooter ever) that needed quite a bit of love underneath the body panels to say the least. I know this video is almost 10 years old, but this is THE BEST explanation of carb adjustment, what parts are what, all around fantastic! This helped me solve why my brand new carb was boggin down on acceleration , but mainly when coming to a stop . Thanks so much for the video, much appreciated still in 2022!
Thanks for watching! I have many newer Chinese scooter videos you might like. Check out the playlist here: ruclips.net/p/PL1_JDBt1LSiJQETjZiOFXBKtv-ZzfqEx0
As far as RUclips tutorials go, this is one of the most helpful and practical ones I've seen.
Clear instructions and explanations.
Now I have a much better idea of how to take care of my little Wolf RX-50.
I end up riding about 500-700 miles a week due to my work, and I can already tell (at 1500 miles) that my current carb will need to be cleaned and adjusted often.
I have been wondering if I can install a higher quality carb as well, since I'll be replacing the ignition, intake, and exhaust in the next few weeks.
Outstanding explanation, your the professor of gy6 carbs, thank you!!!!!!!
Oh yes, one more thing Paul. You certainly know the art of teaching and the teaching paradigm! Thanks again.
Thank you! I'm glad you liked the video. I have a newer video on my channel, about the 50cc carburetor (very similiar to this one) where I explain things much more clearly. ruclips.net/video/iCGjVRyN6YU/видео.html
Thank you Paul
Clearly one of the better videos on carb tuning.
You describe and show it clearly, I learned it here!
Thanks
THE BEST explanation about these carbs that I have seen so far ( and I have seen a lot)
Awesome job. I finally understand how jets work. Either it clicked after all these years or you knew how to teach us. Props for a great teacher. Thank you.
Amen
by far the most intelligent and well presented on you tube. congrats
Still viewing after 10 years, great video to fall back on.
I got to say you did a good job on explaining the carburetor however I learned that when you open the throttle the air increases not decreases because the throttle body plate opens up more as you accelerate allowing for more air and fuel mix to enter.
Wow, you are the most pro expert in carburetors I have ever seen. Great experience to watch your presentation.
You save my week! Cannot find why my Tomos Velo didn't idle anymore. With your video, I discovered that the idle jet was clogged. Your sharing was greatly appreciated here!👍
Dude I wish I watched this when I first bought my kawi 600 lmaoooo quad carb…. I have learned so fing much that this video was a great course for anyone learning right now. I bought a scoot for my mom and dove into this video to help me on that single carb and LAMO THANK YOU MAN YOU ARE HELPING SO MANY PEOPLE. O2 sensor is nuts btw you are insane
Thanks for watching! I made the oxygen sensor setup a little complicated. You can simply buy a gauge and skip all the electronics work.
This is by far the best and well explained video of how a carb work!
Seriously the best carb video. I’ve had so many unanswered questions with other videos but you seriously nailed every one of them.. when you decided to tell us how to tell if you’re running lean or rich or if you have the right jets I was soooo happy. I just ordered a gy6 for my ruckus for a swap and this was so helpful. Thanks again.
Your a genius and that was a great video. I think its the best explanation on the planet, I mean that. Thank you for using the proper terminology and referring to each part by name. It really helps when you know what to ask for when buying replacement parts. Thank you.
The easiest way to determine the mixture is by looking at the color of the plug. It has to be brown, not white or to dark like black. Because it is a carburetor engine. Of course the 02 sensor and gage is a great idea. Great video. Thanks
This is one of the most precise, complete and well done instructional videos that I have seen on the 'tube. Kudos.
This was the most excellent video on the subject. The details, the explanation, the testing at the end.. great job!
Hi, my name is Matthew Murphy. I live in Charlotte Nc. I have a 150cc Chinese motor scooter. I recently had to rebuild the upper cylinder head. I also had to rebuild the carb. Broken jet needle. I just wanted to say Thankyou. The carburetor adjustment tutorial was very helpful. Keep rockin!
So back in 2012 when I turned 18 I bought a 5th hand chinese carbed motorbike for £550 that after a day of riding kept cutting out while idling, so then i took to the mechanics and they fixed it, which lasted a day then it fucked again and would rev to like 7k rpm on idle. I had no clue what was going on and was frustrated. I was too poor to keep going to the mechanics at the time (working £5 per hour part time, lol) and so eventually I sold the bike and unfortunately never rode again since.
Its amazing how much googling I did to try and figure out how to deal with my problem and how I couldn't understand anything from the resources I found back then. Now that I watched this video I completely understand what was going on. Your explanations are so good! Gutted that this video wasn't around back then!
Since I'm back in the market looking to buy a Chinese scoot from new (I'm on £18 an hour now! yay!) your videos give me the confidence that I could maintain it. Thank you so much!
Most Chinese scooters are horrible quality. Even though I'm a mechanic and can fix them, at one point I found I was spending $100 per month fixing my stupid scooter. That made it more expensive to drive than a car! A few scooter brands from China are a bit better. I'm currently riding an eTon sport 50. It's made by SYM. It's been running perfectly with no problems at all for 4 months. That's pretty impressive. SYM scooters is a Taiwanese company but their scooters are manufactured in China. They are better quality than most Chinese scooters. You can also consider Lance scooters. 2010 and newer models are made by SYM, and are good quality. Another brand to consider is Kymco. They are also from Taiwan. Japanese scooters like Honda and Yamaha are definitely better, but if you don't want to spend that much money, you can go with SYM, Lance, or Kymco.
Good God I just met the MAN!!! Big BIG props for this video Mr. Shpakov!!! Indubitably phenomenal! Many thanks! ...Class dismissed!!!
great video man. i searched around for hours trying to find one that explains it like yours. i just installed a new carb on my 50 and it was bogging a little past half throttle. moved the clip up a notch and it smoothed right out. thanks bro
Thanks a bunch man, been trying to troubleshoot a new scooter sucking to much gas and running high at idle. This info was all I needed. awesome job!
Not to go into too much hero worship or anything, but THANK YOU! YOU saved my bike! 2008 Znen/Lance Vintage 150-T. Kept acting like it was flooding when I accelerated, sputter, cough, die.
After following your instructions, got the carb adjusted so not only does it run again, it goes batshit.
***** Quick question: shouldn't the carb sit firmly on the motor? I've noticed while working on mine that the carb moves up and down while the motor holds still...
jaethenfalcon
The carburetor is attached to the rubber intake manifold on one side and the air filter on the other. It is normal for it to move. Just make sure the bolts and hose clamps are tight so you don't get air leaks.
This tutorial from 50cc to 250cc This screw changes the air to fuel ratio at low speeds. It shouldn't need much adjustment, but the way to do it is to turn the screw very slightly (1/8th turn) and see if the idle speed goes up or down. If it goes down, turn the screw back 1/8th turn to where it started, then 1/8 turn in the other direction and see if the idle speed goes up or down. If it goes down, turn it back to where you started since you didn't need any adjustment! If the idle speed goes up, continue turning the screw in 1/8th turn steps until the idle speed is at a maximum. If it starts to go down, turn it back to get the maximum idle speed.
You may need to go back to the idle speed screw to lower the idle speed if it's now too fast. So the basic procedure is to set the fuel/air mixture to give you the fastest idle, then use the idle speed adjustment to set the speed to the lowest rpm that gives you smooth running.
If the scooter idles well and runs fine at low speed, but has problems at high speed, the problem may lie inside the carburetor with the main jet. The fuel/air ratio at higher speeds is set by the jets inside the carburetor and to get at them the carburetor has be be removed and disassembled. This can be a tricky job as the parts are small and delicate. The good news is that these carburetors are quite cheap. You can get a new one for $50-$60, so if you can't make your scooter run smoothly and you don't like the idea of taking the carburetor apart, you can always replace it!
@@Soglesby1222 is it exactly the same carb? If it is then with your new carb check that it has same sized jets etc and if it run perfectly on your old carb then you back the screws in and count how many turns it took and put same settings to new carb and if still not running comment here i can help
@@Soglesby1222 i think you might just have wrong jets or leak somewhere. Did you install all the seals cuz if you just screw the new carb to the head without any seals then it will have leak and will not run good at all
@@Soglesby1222 did u get it running?
@@kevinstearns4198 of course he has been tuning his carb for a year
This has to be the single best carb tuning video out there! There is so much information in this video great job dude. Like the O2 sensor hack :)
This video helped me so much, I even go back and look again sometimes and see something I looked over, a lot of information. great job
EXCELLENT video--exactly what I was looking for. Pretty much all other videos on this subject focused only on the jets, maybe on that vacuum pin, but left other info out
Gosh, you're a one man one episode academic machine. Thank you.
I now understand how these work, bravo uploader because 20 minutes ago that was unfathomable
best carb tuning video I have ever seen! thank you so much
ya seriously this is so well explained for people who know nothing. Thanks!
Very detailed and informative! Not what I was looking for, but exactly what I needed!
Paul, thank you for your help. I recently took the carb out and cleaned it and put it back on. I had a feeling the best option was to replace it. I will try this and hope for the best.
I must say you should be a teacher well done
Outstanding video, very good technical explanation of the parts and what they do. You deffently answered my questions. Thank you.
YOU are the man I have the exact same carb on my Tao Tao 150d ATV and have been trying forever to fix the stalling idle problem basically where you let off the gas and it dies.
Excellent video. The Chinese rubber hoses leave much to be desired, I would suggest that they be replaced with decent hose within 2 years.
A tip to fill the carb bowl; I disconnect the hose on the "Y" join that goes to the fuel valve and suck it. This opens the fuel valve and fills the carb.
Tuning my GY6157QMJ after installing new muffler. Backfiring a bit. Way more than one turn on mix-air screw. I think one will do. Your video helps. Thanks...
Simple, clear and through! Very well done! Thank you!
Man I wish you lived near me! I'd definitely love some help with my project I'll call it!! Love your videos and God bless!!
Thanks for this video. It's super helpful in understanding chinese carburateur which can be kind of confusing
Thanks a lot for sharing Paul very helpful ..greeting from Algeria more post like this it a real joy .......
Well done. You answered a lot of questions that were rolling through my mind concerning the fuel to air ratio and jetting. Great job!
You should probably have mentioned that it's very easy to over heat an air-cooled engine by running it too lean.
good point!
Wym?
@alienlifestyle3768 lean fuel mixture will overheat the engine. A little bit rich is best. The fuel helps cool engine down and air cooled engines are easy to overheat.
@@WhitefolksTnope, lean above stoich condition will reduce temp
@@doradoridoyou have it backwards
Very good job with your explanation of theory and jetting.
The engine backfire on deceleration is also caused by the too lean air/fuel ratio - A lot of people think that the backfire/popping in the exhaust is caused by too rich mixture, but it's actually the other way round.
Im tryna make my moped pop how do i do that mann????
Where have you been hiding, awesome video. Make one rebuilding a 150cc engine, hell I will buy it.
Mine also has the non-adjustable needle. I purchased one with a C-clip and it was way off, so I ended up using the original. Adding spacers to the flat top needle will make it more rich. If you want to go more lean, you can get a smaller main jet. If you still need to go more lean, you can replace or modify the piece that the main jet screws in to. I didn't show it, but I actually did that - I shortened the main jet mounting piece by about 1.5mm to lean it out.
That is a very controversial
topic and noone seems to agree on the same thing.When you lean the idle circuit and you have a high speed variator with lighter roller weights ,fuel starvation at take off over heats the engine and it runs rough.That screw only works like a 1/4 of a turn from the closed position,opening it higher will only make it leaner.It is better to leave at the richest spot and upgrade the pilot jet.I'm currently using a 40 and a 102 main jet and it runs like a wild horse the entire throttle band.Actually that screw when turned counter clockwise leans the engine.A spark plug check won't lie..I know you know about this and in no way am.i criticizing your great content.It is exactly because i know you know that i'm writing this comment.Thanks for thr great video
I like the way you explain the carb it helped me understand easily
Very nice video,learned a lot about my POS - like the Riding breakdown!
Wonderful video!!! Great filming and commentary plus practical demonstration!!!
Excellent video. Helped me understand how the carburetor works. Thanks for the video.
Outstanding! Thorough and understandable, thanks for the time and effort
This is brilliant! Very informative and I love how stealth that af ratio gauge is
God bless you ,you helped much,,i didnt know whereis where after i took it out and didnt remember where the pipes goes..now ok...greetings from greece,
Well done on a topic you know well. Your detailed explanations are well balanced with just the right amount of technical information. Coupled with a well edited video with unnecessary clutter removed (i.e. showing all screws being tightened) a well presented video. A point of improvement, Idle screw adjustment turns from closed should be consistent, i.e 1 -1 1/2 turns .
I have subscribed well done.
Thank you for the compliments! I have a newer carburetor tuning video here: ruclips.net/video/iCGjVRyN6YU/видео.html it's for a 50cc, but the procedure is the same as the 150, and I explain things much better.
Great disassembly / reassembly talk and video and interesting data on road test. Thanks.
Hi - great job on this video! You only missed one small area, and that is the "Needle Jet". This is the brass tube (yes - this tube is actually a jet!) that the Main Jet screws into. If you look closely, the opposite end of this tube (will be the top side when the carb is in the functional orientation) has an opening that the needle goes into - this hole is very accurately drilled (hence why it is called a "jet") and is actually the functional end of the tube (jet), and if you remove it you will find that this Needle Jet itself has a numeric value like the other jets. This "accurate hole" on the top side is the part that the tapered needle uses to meter the fuel. You probably noticed that the carb slide (diaphragm piston) moves something close to a full inch of travel... and this matches the tapered part of the needle. The Main Jet is too short to function over this large range of motion... When the needle is high enough (at about 3/4 throttle) the narrow part of the needle in conjunction with the opening in the Needle Jet allows the maximum amount of fuel... it is at this final point that the Main Jet finally takes over and ultimately limits the amount of fuel going into the engine! The main jet only functions at something close to full throttle. The Needle Jet + Needle do most of the work from about 1/8 throttle to 3/4 throttle! This is just a technical detail - your message is the same and this was indeed a Great video - thank you for creating and posting!
Hi I got a 2023 kaik flash moped it’s a 150cc Chinese brand I’m pretty sure but I don’t know much about them and I heard if I get a bigger exhaust(I got one put on today) that I might need to do something with the jets as well or it could mess up the engine. U seem to know a lot about them so if u see this could you let me know what they meant by that I have no clue just not trynna mess up the engine
@@DanielLopez-vi6nq Sure No - problem. If you get a higher flowing exhaust (less back pressure), you will likely benefit from going up a size on the main jest and maybe adding a spacer to the needle to give the engine just slightly more fuel. The best way to know is to pull the spark plug out... it should look light to medium tan on the inside porcelain part. If it is almost white, then the bike is running too lean and you need to adjust the mixture to add more fuel. Look for more videos on how to put a washer under the needle to raise it up very slightly... they probably sell jet kits for your bike... watch more videos and write to the creators of the videos - they will be very helpful too!. Good luck!
@@DanielLopez-vi6nq It won't hurt your engine to ride it with the new exhaust... just over time it might wear your engine parts faster, and also not give you as good a performance as you should be getting. Good luck...
Good comprehensive tutorial mate 👌
Best explanation I've ever seen. Thank you so much.
Paul, you are great with an engine! I will try to follow your lead, I just bought a 2008 150cc that needs help. I need help too!
for tuning, a wideband lamba is a lot more useful. in the video, it seems to be a narrowband, which is only good for afr 14.7+-0,5
i have a 150cc that used to run ok and then the dash, made of fiberglass started to crack and dismember itself , causing certain switches that were mounted on them to falter and break off. I lost my headlight and was forced to splice inorder to get home one night. Well apparrantly the splice caused the battery to drain and because I have ran the splice from a hot black wire from the high bean switch, which was one of few still attached to the fiberglass surrounding the left handlebars.
Well that just fucked everything up. Once I stopped that connection, I was forced to get jumps with cables, and everytime it seemed to take longer to get the motor started. I also noticed that the run off line from the carb floats was starting to really get bigger each time I was in need of starts.
Now, with a fresh battery, spark still from the plug, this SOB wont turn over. I have taken the carb off 5 times to ensure the jets werent clogged, and that the floats were allowing fill up and when that occured , the gas was being shut off the flow to the carb.
WTF did i do????
The fleebs come and massage the floob and and now you have a full plumbis.Man i take my hat off to you guy .you know your stuff.
you can always drill the jet for a 33 if you really , really need a 33. They have drill bits thats are are even in half or quarter sizes.
you shouldnt drill jets, because they have an inside shape and is intended to be that way
Very well done you explain perfectly just the video I was looking for
This video helped me like no other! Thank you so much, liked and subbed.. make more!
Great video! Very informative. I'm not longer quite as intimidated by my carb.
I hate carburetors..but I have one and I thank you for your teaching.
Super descriptive and knowledgeable! Thank you,great video
I've been really messing with my carb a lot lately. One thing that I changed and just reverted back to was the CDI box. It would pop through the carb at starting at times which led me to beleive it was too advacnced. I recall reading that some of these "performance" box's will advance the timing but also hard to start, so I threw the stock CDI back in and now I can idle at 1k rpms. Running a #84 main jet with #34 pilot. Top end seems weak but im at sea level too so maybe I should go a bit bigger on the main jet.
***** 5 stars V10 A 9 extremely informative thank you
My bro is not wasting any gas👍😅
lol, ur wide angle lens makes the needle jets look bent ;)...Great Video
UPDATE: Fixed my inconsistent idle/stall problem. Found crack in junction of black large rubber carb inlet tube where it joins the airbox....Was letting too much air in and stalling engine. Tested by cosing hand over air intake tube with holes in it and idle was rock steady.
Original Post:Paul..excellent video...One question: I have a scooter that starts and runs (on kickstand) but idle climbs to 4000 and holds then after about 12 seconds, goes back down to 2000, then another 12 secs or so back to 4000 and repeats..Obviously, if I adjsut idle to not be so high, it will stall out when it comes down on its own, so I have it at the 4000/2000 so I can keep it running and driveable. I can ride it and it is responsive, but occasionally at a stop, it will idle down to 1000 and almost dye out unless I gas it (obviously I can;t get the idle climb and drop while it is on the ground running. Another note: Holding the back brake when up on stand idle drops to 2000, if I let go it spins up to 4000 then it will drop back to 2000 on its own (even if I dont hit brake) then goes back up and repeats.
I have cleaned cabs jets, set the carb needle, adjusted the valves, adjusted the throttle cable, adjusted idle mix screw, adjusted idle screw ..... scooter seems to be running powerfully and responsive....just need to figure out this idle climb and drop and possible stalling when it drop even further. What advice do you have? (vacuum leak???) THANKS!
Very clearly explained!! Good lad!
World class pedagogy.
the vacume operated needle valve there are two types of needle valve . the adj, are different the washers type are for the flat top and the c clip needle you move the c clip up or down a notch to ADJ. this type
you was speeding through that school zone lol thanx ill have to watch it a couple times
Thanks Paul truly Enlightened by your insight thanks and a great video clip
Backfire through the muffler while slowing down is pretty fun tho 😂
Okej mycket bra video!!!!!!. Tack gode gud för att jag förstår all engelska. Och detta är inte tack vare skolan!!!! Grund skolan är bara skit enligt mig.
Hi Richard, from sources I've read online, people say a larger intake makes it run more lean. I disagree with this, since the metering in a carburetor is done as a ratio of how much air actually gets to the carb. Either way, you do benefit from an aftermarket air intake, like the UNI filter. I noticed a much better throttle response in mine. Have you tried adjusting your intake and exhaust valves? Mine were set wrong from the factory. Fixing it is pretty easy actually.
My scooter will get up to about 55mph now, at 4500ft elevation. I had to lean the jets way down. Before I moved here I was at 700ft, and it would hit about 65mph.
How did you disconnect the throttle cable? I unscrew/loosen both screws and the throttle cable is still connected.
I pretended that you were Ed Norton teaching me about carb tuning. you sound like him.
this is how you make a goddamn tutorial, everything you could need
WoW! How in the H*** you put an O2 sensor on that bike with an gauge. You is the man.
Jetsrus .com has a wide variety of needles. That's where i got mine. They have a lot of different sizes and taper diameters. If you just need to go more rich or more lean, I would recommend using spacers (also available at jetsrus)
5 years later------still a great video;that O2 sensor and readout tell the tale; wonder if it is a wideband,or a regular sensor?
Thanks! I'm too cheap to buy a wideband O2 sensor, so it's a regular heated O2 sensor. You don't really want a wideband sensor anyway, because if your A/F ratio is out of range of the regular O2 sensor, it's wrong and you need to re-jet your carburetor.
Thanks for a super helpful video. You explained everything in simple easy to understand terms that even an amateur like me gets. My carb is a little different, and my application is WAY different ( motorized bike, 4 stroke, 100cc kit) but I still think you explained enough to get me thru it.
One question, little short hose right behind the electric choke. Goes to nothing. What is that? And do you know the voltage that goes to the choke? I'm assuming 12-15, but not sure. Not gonna try til someone can explain.
Thanks again for a terrific vid
When you took the floats off I saw a little piece fall into the carb I hope you got that out.. :)
yes.5 sec later is this piece in his hand.
Thank you Paul. Nice demo.
Damn. Well done video bro. Impressive.