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
As far as TH-cam 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.
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.
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: th-cam.com/play/PL1_JDBt1LSiJQETjZiOFXBKtv-ZzfqEx0.html
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!!!
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. th-cam.com/video/iCGjVRyN6YU/w-d-xo.html
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.
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
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.
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.
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!👍
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!!
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
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.
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.
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.
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.
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!
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
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
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.
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. 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.
@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.
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...
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
Great video!! I’m glad you were generic saying it pertained to many of these “Chinese” scooters. Quick question- my scooter starts and generally stays running (I find sloshing around the fuel helps) but takes forever to warm up to the point where it doesn’t stall when you roll on the throttle. Is that more likely to be the auto enricher or the idle mixture screw? Once it’s warmed up it’s totally fine.
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.
Thank you! The oxygen sensor is a 4-wire heated O2 sensor. I had to guess which wires were heater and signal. With a multimeter set to ohms, you'll get continuity between the 2 heater wires but no continuity between signal and ground. www.jegs.com/i/Bosch/149/15703/10002/-1 and you'll need this bung to mount the O2 sensor: www.jegs.com/i/JEGS-Performance-Products/555/30743/10002/-1 The voltmeter in my scooter is this one: www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2116744_-1 which requires a 5V power supply: www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_297810_-1 You have to be very good with electronics to use that volt meter. If you want something easier, go with something like this: www.jegs.com/i/Innovate+Motorsports/540/3793/10002/-1
Great tutorial, very simple explanations. The link for the air/fuel gauge does not work, can you please post a new link, or the manufacturer of the gauge. Greets
Awesome video, thank you! I was a bit stumped after looking at my pilot jet. It seems it's not hollow all the way through. Is this normal or is mine just clogged? Thank you in advance!
Dude, i want to know more about the o2 sensor you installed with the digital readout. I would like to install that on my ultra light. How about a video where to get the parts and install.
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.
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
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.
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????
excellent video Paul! thanks for all the tips and the very detailed explanations. I've just bought a new scooter, 50cc. I've put about 40 miles on it. It doesn't run out at top end. Idle is good, acceleration is good, but it skips/misses at full throttle. You can tell it's not running smoothly at full throttle. The place I bought from is 60 miles, I called them and they sent me a new carb, I'm wondering before I put the new on one, is there an adjustment I should try on the original before changing it out? I'm not sure if its getting too much gas or not getting enough at full throttle, what should I try first? thanks Charles
Great video. So,if my scooter is working fine,but to lean on acceleration (let's call it leven late,I throttle it,and it start to accelerate after 1-2 sec) and I want better acceleration,what should I do?
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,
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!
Very helpful visuals to understand what's going on in the carburetor. A few questions: 1st, would adjusting the idle mixture screw or adding a spacer to the needle be helpful in making the scooter start more promptly? The way you're scooter didn't start right away due to the carburetor bowl being empty that's the way my scooter seems to delay in starting all the time. 2nd, my stock carburetor has a plug covering the idle mixture screw which can be removed with a screw extractor in order to get to the actual mixture screw. Should I even bother removing the plug?
+Jonathan Morley If your scooter has trouble starting, check these items: 1.spark plug. Replace if it's old. 2.Check inside the carburetor. Clean it thoroughly if the fuel ever got dirty from sitting. 2. Check the fuel shutoff valve. It's near the gas tank and has 2 fuel lines and 1 vacuum hose. Check it for leaks, and make sure the vacuum hose isn't loose or cracked. 4. Replace the fuel filter if it's old. 5. Adjust the carburetor. Drill out the idle mixture screw cover. The idle speed (near throttle) and idle mixture should be the first things to adjust. 6. Check idle enricher. It's the electronic part of the carburetor. Remove it from the carb so you can see the needle on the end of it. With the enricher plugged in, turn the key on. It should take about 2 minutes for it to move. If it does nothing, test it further with a multimeter and replace if needed.
Hey Paul. I have typical GY6 Chinese Scooter 125 ccm (152QMI). And I have two problems. 1st: initial acceleration up to 20 kph (about 13 mph) is VERY slow, the scooter seems like it doesn't want to get to higher RPM, it's very hesitating. Once I reach about 20-25 kph (13-17 mph) the acceleration is good. I already replaced belt, variator and put aliexpress "dr. pulley" sliders. Could it be small pilot jet? The second problem is low maximum speed. Only 80 kph (50 mph). I had GY6 before and the acceleration was WAY better and the maximum speed was like like 90-92 kph (56-57 mph) and I don't know what to do. Really hoping to get an answer, I love your vids. Thanks.
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: th-cam.com/video/iCGjVRyN6YU/w-d-xo.html it's for a 50cc, but the procedure is the same as the 150, and I explain things much better.
Thanks for posting this video! Any tips on how to install the air-fuel mixture device? I'd love to have that on my scooter as I keep tuning it. Much appreciated!
www.jegs.com/i/AEM/017/35-4005/10002/-1 www.jegs.com/i/NGK-Spark-Plugs/739/22060/10002/-1 www.jegs.com/i/JEGS-Performance-Products/555/41417/10002/-1 The shopping is the easy part. The installation requires cutting open the muffler and welding in the O2 sensor bung. Then you have to figure out the wiring. The 4-wire O2 sensor has signal, ground, and 2 heater wires. The heater connects to the lights on the scooter, and makes the O2 sensor functional within 30 seconds. Otherwise, you would just have to hope it gets hot enough to work. The gauge is pretty simple, and comes with instructions. I would say it's a very difficult installation.
Paul great video, I recently bought a used yamati 150 which the carb looks the same. It won't start unless use starter fluid even though I keep it in the garage at nights. It does fine 8 hours later when leaving for work. Where can I look to solve this issue?
9 years later I found this video in 2023 and it’s the best explanation I have ever seen , thank you !
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
As far as TH-cam 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!!!!!!!
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.
9 years ago you did a great job of explaining how a carb works.
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: th-cam.com/play/PL1_JDBt1LSiJQETjZiOFXBKtv-ZzfqEx0.html
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!!!
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. th-cam.com/video/iCGjVRyN6YU/w-d-xo.html
Thank you Paul
Clearly one of the better videos on carb tuning.
You describe and show it clearly, I learned it here!
Thanks
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.
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
THE BEST explanation about these carbs that I have seen so far ( and I have seen a lot)
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.
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
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!👍
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!!
This is by far the best and well explained video of how a carb work!
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.
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.
by far the most intelligent and well presented on you tube. congrats
This was the most excellent video on the subject. The details, the explanation, the testing at the end.. great job!
Still viewing after 10 years, great video to fall back on.
Wow, you are the most pro expert in carburetors I have ever seen. Great experience to watch your presentation.
I must say you should be a teacher well done
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.
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.
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.
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!
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!
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
This is one of the most precise, complete and well done instructional videos that I have seen on the 'tube. Kudos.
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
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
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 :)
best carb tuning video I have ever seen! thank you so much
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.
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
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.
Outstanding video, very good technical explanation of the parts and what they do. You deffently answered my questions. Thank you.
Very detailed and informative! Not what I was looking for, but exactly what I needed!
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
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...
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!!
Well done. You answered a lot of questions that were rolling through my mind concerning the fuel to air ratio and jetting. Great job!
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
Very good job with your explanation of theory and jetting.
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
I like the way you explain the carb it helped me understand easily
Simple, clear and through! Very well done! Thank you!
Great video!! I’m glad you were generic saying it pertained to many of these “Chinese” scooters. Quick question- my scooter starts and generally stays running (I find sloshing around the fuel helps) but takes forever to warm up to the point where it doesn’t stall when you roll on the throttle. Is that more likely to be the auto enricher or the idle mixture screw? Once it’s warmed up it’s totally fine.
I am late but have you cleaned the carb ?
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.
Where have you been hiding, awesome video. Make one rebuilding a 150cc engine, hell I will buy it.
***** 5 stars V10 A 9 extremely informative thank you
ya seriously this is so well explained for people who know nothing. Thanks!
This is brilliant! Very informative and I love how stealth that af ratio gauge is
Very nice video,learned a lot about my POS - like the Riding breakdown!
Wonderful video!!! Great filming and commentary plus practical demonstration!!!
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 .......
Good comprehensive tutorial mate 👌
I pretended that you were Ed Norton teaching me about carb tuning. you sound like him.
Outstanding! Thorough and understandable, thanks for the time and effort
Best of the many tuning videos I've watched! What sort of O2 sensor & dislplay did yo use?
Thank you! The oxygen sensor is a 4-wire heated O2 sensor. I had to guess which wires were heater and signal. With a multimeter set to ohms, you'll get continuity between the 2 heater wires but no continuity between signal and ground. www.jegs.com/i/Bosch/149/15703/10002/-1
and you'll need this bung to mount the O2 sensor: www.jegs.com/i/JEGS-Performance-Products/555/30743/10002/-1
The voltmeter in my scooter is this one: www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2116744_-1 which requires a 5V power supply: www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_297810_-1
You have to be very good with electronics to use that volt meter. If you want something easier, go with something like this: www.jegs.com/i/Innovate+Motorsports/540/3793/10002/-1
Paul Shpakov Awesome, thanks!
this is how you make a goddamn tutorial, everything you could need
Great tutorial, very simple explanations. The link for the air/fuel gauge does not work, can you please post a new link, or the manufacturer of the gauge. Greets
Backfire through the muffler while slowing down is pretty fun tho 😂
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.
Awesome video, thank you!
I was a bit stumped after looking at my pilot jet. It seems it's not hollow all the way through. Is this normal or is mine just clogged?
Thank you in advance!
You should be able to see light through main and primary jets. It sounds like yours is clogged and needs to be replaced.
Excellent video. Helped me understand how the carburetor works. Thanks for the video.
Dude, i want to know more about the o2 sensor you installed with the digital readout. I would like to install that on my ultra light. How about a video where to get the parts and install.
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!
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????
Very clearly explained!! Good lad!
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
awesome video! anyway, can fuel injector cleaner helps clean out the gunk that clogging the jet needles?
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.
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????
excellent video Paul! thanks for all the tips and the very detailed explanations. I've just bought a new scooter, 50cc. I've put about 40 miles on it. It doesn't run out at top end. Idle is good, acceleration is good, but it skips/misses at full throttle. You can tell it's not running smoothly at full throttle. The place I bought from is 60 miles, I called them and they sent me a new carb, I'm wondering before I put the new on one, is there an adjustment I should try on the original before changing it out? I'm not sure if its getting too much gas or not getting enough at full throttle, what should I try first? thanks Charles
Great video. So,if my scooter is working fine,but to lean on acceleration (let's call it leven late,I throttle it,and it start to accelerate after 1-2 sec) and I want better acceleration,what should I do?
My bro is not wasting any gas👍😅
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,
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!
Very helpful visuals to understand what's going on in the carburetor. A few questions: 1st, would adjusting the idle mixture screw or adding a spacer to the needle be helpful in making the scooter start more promptly? The way you're scooter didn't start right away due to the carburetor bowl being empty that's the way my scooter seems to delay in starting all the time. 2nd, my stock carburetor has a plug covering the idle mixture screw which can be removed with a screw extractor in order to get to the actual mixture screw. Should I even bother removing the plug?
+Jonathan Morley If your scooter has trouble starting, check these items: 1.spark plug. Replace if it's old. 2.Check inside the carburetor. Clean it thoroughly if the fuel ever got dirty from sitting. 2. Check the fuel shutoff valve. It's near the gas tank and has 2 fuel lines and 1 vacuum hose. Check it for leaks, and make sure the vacuum hose isn't loose or cracked. 4. Replace the fuel filter if it's old. 5. Adjust the carburetor. Drill out the idle mixture screw cover. The idle speed (near throttle) and idle mixture should be the first things to adjust. 6. Check idle enricher. It's the electronic part of the carburetor. Remove it from the carb so you can see the needle on the end of it. With the enricher plugged in, turn the key on. It should take about 2 minutes for it to move. If it does nothing, test it further with a multimeter and replace if needed.
Hey Paul. I have typical GY6 Chinese Scooter 125 ccm (152QMI). And I have two problems. 1st: initial acceleration up to 20 kph (about 13 mph) is VERY slow, the scooter seems like it doesn't want to get to higher RPM, it's very hesitating. Once I reach about 20-25 kph (13-17 mph) the acceleration is good. I already replaced belt, variator and put aliexpress "dr. pulley" sliders. Could it be small pilot jet? The second problem is low maximum speed. Only 80 kph (50 mph). I had GY6 before and the acceleration was WAY better and the maximum speed was like like 90-92 kph (56-57 mph) and I don't know what to do. Really hoping to get an answer, I love your vids. Thanks.
World class pedagogy.
Very well done you explain perfectly just the video I was looking for
I hate carburetors..but I have one and I thank you for your teaching.
Best explanation I've ever seen. Thank you so much.
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: th-cam.com/video/iCGjVRyN6YU/w-d-xo.html it's for a 50cc, but the procedure is the same as the 150, and I explain things much better.
Thanks for posting this video! Any tips on how to install the air-fuel mixture device? I'd love to have that on my scooter as I keep tuning it.
Much appreciated!
www.jegs.com/i/AEM/017/35-4005/10002/-1
www.jegs.com/i/NGK-Spark-Plugs/739/22060/10002/-1
www.jegs.com/i/JEGS-Performance-Products/555/41417/10002/-1
The shopping is the easy part. The installation requires cutting open the muffler and welding in the O2 sensor bung. Then you have to figure out the wiring. The 4-wire O2 sensor has signal, ground, and 2 heater wires. The heater connects to the lights on the scooter, and makes the O2 sensor functional within 30 seconds. Otherwise, you would just have to hope it gets hot enough to work. The gauge is pretty simple, and comes with instructions. I would say it's a very difficult installation.
you was speeding through that school zone lol thanx ill have to watch it a couple times
Paul great video, I recently bought a used yamati 150 which the carb looks the same. It won't start unless use starter fluid even though I keep it in the garage at nights. It does fine 8 hours later when leaving for work. Where can I look to solve this issue?
This video helped me like no other! Thank you so much, liked and subbed.. make more!
Paul--I have seen a lot of videos and yours is outstanding!!! One question: where do you get all those nice little parts?! :-)
Great disassembly / reassembly talk and video and interesting data on road test. Thanks.
Super descriptive and knowledgeable! Thank you,great video
WoW! How in the H*** you put an O2 sensor on that bike with an gauge. You is the man.