Wow you are good teacher. Thanks. I am having issue on a ttr110 tried different jets to control bog at full throttle but now I have good ful throttle but no idle and when I change pilot I get full open bog I'm so confused can't get both to be right. I have a air screw and a welch plug do I have both air and fuel screw? I thought u said there is only either or.
As far as carb adjustments, this is definitely the best video ive watched so far. Also explaining how it works. Thanks a bunch. I feel way more comfortable going foward with my 1st attempt
Wow excellent Matthew, I have been mechanic on these for 55 years but some mixture screws didn't give me the proper response..you have taught me how to better decide the pilot jet configurations..Who says you cant teach an old dog new tricks..lol Oh by the way..the carbs are already synchronized before this video?..Yes? Liked and subscribed..thank you very much. Peter
I was a tech in a Yamaha dealership back in the eighties and Yamaha said we had to adjust all carbs while using an e-gas analyzer to spec, always too lean, and replace the plugs or they might void warranty. Honda wanted us to do idle drop adjusting which honestly worked much better and no expensive, delicate equipment needed
My bike doesn’t seem to have powerband or the full power it has it kind of feels like too much air or something but before it would bog and just cut off but the bike is a 2022 yz85 and I’m confused it went from fresh to not I cleaned the jets and I tried to mess with the floats and even then out with the top of the carb and cleaned the air filter and changed the spark plug if I don’t know what to do I’m sure it has to do with the carburetor
Why would the pilot screws have to be a 1/2-1 turns out? Both are the same and it just revs higher as I turn screw in, it doesn't bog down till I turn it out around 1/2-2+.. please help me when you can. Thanks!
@@Muchteba if no powerband try check your powervalve, it could be stuck with too much carbon buildup..after riding at wide open throttle for about 10-20 second, immediately stop the engine and remove the sparkplug to inspect the colour to see whether its too rich or lean..
You might have just saved my bike. Stay tuned! Thanks for taking the time. The most informative video on the subject that I've found. I can't wait to get home and try this.
I have a 1980 yamaha xs1100 special and I have been having issues with setting my idle after rebuilding the carbs. this whole video gave me sooooo much help in understanding how this system works, I thought I had an air screw, turns out its a fuel screw. I'm an automotive tech and never messed with bikes before now and I appreciate how in depth you got explaining this.
Watched tons of videos trying to figure out what i need to be looking for, for my carb and no one has explained it as clearly as you do. It all suddenly made sense.
Really want to thank you for all your very informative video's, I recently bought an 82 XS 650, and since then I have learned how to make noise out of money!
Very good and helpful information. The popping noise you spoke about, is ignition noise (picked up by camera's audio input), from the motorcycle when running.
Great video, very comprehensive. After removing the welch plugs on my '94 Kaw Voyager 1200, I discovered that two of the pilot screws were buried (zero turns out) and two were about 1.5 turns out. The plugs looked factory, so it's shocking that Kaw (or Keihin) would have messed up so badly. The guy I bought the bike from told me that it was originally sold in CA, so maybe that has something to do with it.
Thanks man, great explanation on how it all works. I recently resurrected an 86 vmax that had sat for 10 years, bad gas, rusted tank, frozen carbs, etc. Runs great at upper rpm but won’t idle without choke. I should have removed the factory set pilot screws before I soaked the carbs, as you mentioned, probably the issue. Going to do it now. My thinking, since only has 5k miles, was that factory setting probably correct. I might even see about getting larger main jets, but the thing is insanely fast the way it is.
I also use spark plug color as indicator, trying to aim to a brownish color. Starting from being too rich with carbon black spark plugs making adjustments down and always running the bike for at least 30 minutes, with highway parts and check again color until right. It can take several days but it seems the most precise method without the use of fancy tools, what do you think ?
Already liked that video last year when I found it, looking for info about carb and rebuild and tuning but want to say thanks again since I completely rebuild both of my 96 1100 Virago carbs and currently having some issue to tune it well. I looked and dozens of videos but this one, I I look at again, clarified everything. You are very clear and really take the time to visually explain how the carb works. Thanks man! really nice work!
I'm impressed with your knowledge and ability to teach. Taking the time to illustrate the theory is top notch stuff. I learned a lot, and really appreciate the time and effort you put into creating this video. I have an '86 Ninja ZX600R, purchased in '90, and it's always suffered from being too lean in the pilot circuit, and falling on it's face when the throttle is rolled on. I've had the carbs off and apart for cleaning, probably 3 times since purchase, (learning more as I go along in life) mostly due to leaving it sit unused for long enough that the fuel went bad in the carbs, but I didn't know about how jet sizing has an effect on mixture ratio, even though the pilot screw might be out enough that they idle is good. I've even synched them, and although there was a noticeable improvement, it's never be perfect. I'll be I could go a size or 2 up, and cure the issue, if any company is making jets still. Thanks again!
Oh, " and I also just made this number up" lol....regardless...I just took some of your advice! Very nicely done btw! I've ordered two Main jets size 125 , two Pilot jets size 42 and 2 shim for each Slide Needle for my 84 750 Shadow!
Thank you! This was very well explained and helped me to set up my carbs which wouldn’t idle after a rebuild (where another person said to set them at 2.5, but that wasn’t right for where I live / what the carbs are set like here)
I have Mikuni VM26SS carbs and they have both fuel and air screws Just thought I'd point that out to ya but great info u always give and keep up the good work 👍
I always ran lean because it gets great efficiency and economy. That extra power gain you get from running rich is not important unless I go to track. When I do track I retune it to slightly rich. Good video.
I’m pretty sure that I could have done the valves myself and got it running sweet but it was well worth the money spent for piece of mind that it was done right. In fact the guy that did the work rides a Radian also. He said he was jealous at how nice my bike ran. I guess I got a good one.
my 90 gs500e's stock spec is 3 turns out. When on the highway at speed, if I slowly roll of the throttle and then back on again (to go +/- highway speed) it pops as I turn the throttle. Doesn't pop anymore after the throttle is turned 1/8. These are set to run lean for sure, so my thinking is 3.5 turns out, which is what I had it at prior to resetting it. this video is awesome. greetings from Chicago!
I probably do. Maybe ill get some new jets. You should also mention in your video that most of these non-oem jet kits come with inferior brass jets. that was a problem I had with the rebuild kit I got from ebay. i ended up not using them all. but the float bowl gaskets were good!
on the Mikuni BST33's that the GS's come with, the thinking is 3.5 turns out is the most you can do anyway, so if this doesn't solve the problem, new jets will be the answer. Why am i throwing parts at a 29 year old bike?? Because it had 10,500 miles on it when I bought it.
My problem is I have new mikuni rs36-d8-k carbs on my yamaha xj1100 amd jetted for the engine and per directions it says to turn them out ⅛ to ½ turns out max but it doesn't say from a light seat, fron a turn out, or anything in the directions. A light seat is something that is hard to determine because it is seated against a oring and each carb has a different feel and look when you look at each pilot jet screw with the carbs off so I've ordered a colortune to see where thigs are at. Your video is a great watch for sure and explains things perfectly.
Thank you so much for this educational video. I have an 82 Maxim xj1100 and have been going crazy as to why it wasn't idling without a full choke. Can't wait to try this!!
This is a good video. I hope between both your videos and mine, maybe people might start to understand how to do this on their own. But still I think people don't want to spend the type testing, changing a setting, testing, and so forth.
Thanks. Tuning can be a PITA, however with this circuit the answer is in the screw setting. Don't even have to ride it to determine if it is lean/rich.
Right, but novices I think lack the analytical mind we may have. This video builds on our previous information around the topic. Too bad it can't be better centralized. I have tried to do that on my website, and I might embed your video there.
@@HTMR my vtx mixture screw was completely burned out and crudded up with rust and kept playing with the mixture not realizing till I dug deeper and once I cleaned it up it was much more responsive but now I’m dealing with slight hesitation during acceleration using barons set with 210 but they didn’t assign numeric value on pilot
Just stumbled on you channel oh boy you just have answered a annoying problem with my 1990 ZXR750H2 (uk) my idle is slow to return to normal I do have mods I'm running micron headers to a SP stubby can with K&N filter im running 130 main jets high speed running is spot on. I do sometimes have a problem with the bike cutting out when hot at traffic lights your explanation of the pilot jets which I have set at manufacturing setting one and three quarters turned out looks like I need to turn them out further looks like mine is running lean and the fuel is evaporating before its pulled into the engine . I have uploaded a video of my bike to my channel me revving it and you can plainly hear the rpm slowly returning back to normal idle. Great video your never to old to learn thankyou so much for this video. Happy New Year and I hope 2021 is a good one 😎👍 ps you have a new sub
thank you, this is the closest any video has gotten to providing any information that I can relate to the hitachi hsc32 carbs on the 1980 yamaha xj650 i recently acquired, in fact the carbs are out laying on my bed from me just getting through 2 hours ago putting them back together again for the 5th or 6th time. there is no information in the manual for the fuel adjusting screw it just says "preset (no datum given)" so now I have a guide line to work from, thank you again......
@Animal Mother haha i brought it away for ultrasonic cleaning to an motorcycle shop and they cleaned it en adjusted it for 50 euro 😃 so I never did it 😑😁
BEST VIDEO ON RU-vid! QUESTIONS: I backed my idle screw all the way out on my vtwin 1100 vstar, and it still idles at around 800 RPM. When I lean it out idle goes down and when I richen it the idle goes up. But where it idles smooth and fast is too fast for the lowest idle screw setting. Also, note that when I close the AF screw all the way the bike still idles and will not stall even with the AF screw all the way in on the front cylinder. Also not that the rear cylinder AF screw has no real effect to any change I make to it, except the backfire pops, when I lean it out and less backfire pops when I richen it, but it does not have any real effect at idle. Only the front carb seems to affect idle. I bought this bike second hand. I think its time to ditch the carbs and buy another used set and start over?
Well. . .I have looked and looked and this is so helpful, beats everything I've seen, so very well done and much appreciated. I could use a few minutes of private tutoring, are you available?
Thank you for this video and explaining this in depth. I have a 08 kawasaki teryx with the 750 and I don’t think the carbs have ever been set right for the riding terrain here in Oregon. So again thank you for taking the time to help
Excellent tutorial, thank you! Currently working on tuning the carbs I just rebuilt on a 1994 Yamaha XJ600. My first time doing it, so it's a minor miracle that they don't leak. 🤣 Idles fine but acceleration is poor. I have a MotionPro sync tool I'll be using, and this method to work on the pilot screws. A wideband O2 sensor was a good method suggested, but pricey and involves welding. This looks much more doable for me. I stepped my OEM pilot jets up from #17 to #20. Main jets are stock. We'll see how it goes!
Hello! Thanks for the detailed explanation! We are also in the the process of the tuning the fuel screws. Two questions if someone knows to help out 🙏 1. Before starting the process, where should be the idle revs configured? High, low or manufacturer suggested? Or something else? 2. What happens if the screws are in a location where it is probably impossible to tune them while the engine is running. Any tips and tricks? P.S. The bike we are trying to tune is Honda Cbf 600, 2004. Thanks!
Hey man thanks a lot man I have Ben putting back a Yamaha 2006 r6 for 3 years now..it was throttling good and reving good..I had replace some head o rings n start the bike n it stop reving and a wile after it start to missing n he other thing as well the throttle body get tight..I take the plugs our clean them n free up the throttle body as well n check all wiers n all is good knick ..thanks a lot man n I'll try the 3 turns out n see what..keep what you do best by Charing your nalage..👍💯🔐
On a twin carbs bike, the pilots screw adjustment need to be the same or it can be different from carb # 1 to carb # 2 ? Like 2 turn out on the carb # 1 and 2.5 turn out on the # 2 ?
I did not read here where anyone talked about checking actual air flow on each carburetor. I used a device that had a rubber seal. Place the device on carburetor # 1. There was a ball that floated in a clear tube. Adjust it until the ball floats in marked center. The place the device on # 2 carb. If the ball was not centered, you got to adjust carburetor linkage to sync the carburetors. Same with the #3 carburetor. You need the exact air flow on all carburetors. Last adjust the mixture needles. The only way to get it done right.😅
I do have a suggestion. Since this is such a HUGE topic. I would make ONE video on just air screw adjustment and ONE video on fuel screw. Explain about the AFR for each and how to select pilot ideal turns out and max turns out before changing. It can be confusing when you think about one or the other. I think it would pay off in the long run. Since I am a tuber i know how that works.
After hearing it I can tell you that the popping on your audio is caused by rf interference from ignition system discharges effecting the electronics in your audio equipment.. Better audio curcuitry should have better shielding against it. Also possibly some form of suppression/filtering on your ignition system but I don't know if that can be done.
Hey Matthew! Great videos you are truly a professional. I have a problem with ground issues. When I start my bike with jumper cables and remove the ground clamp i get a really good set of sparks. I have pulled the stator. voltage regulator it all seem to check out. Is something wrong! Build bikes for everyone. Merrill
BTW... I am struggling with my 1400 '96 Intruder. I wanted to clean/rebuild the carbs and realized I need to swap out my sync cable and throttle cable because both were VERY warn! Well when I reassembled the carbs (I am very green at this) I must have made a mistake. But listening to this video I feel I have one carb (the rear) that is way too rich and the front carb WAY WAY too lean (the air box was even VERY hot after 7 minutes of running at idle)! Breaking down how the pilot circuit works is going to be SO helpful when I go back to double check the carbs. I also did not set the floats so that could be an issue as well. Learning as I go so thanks for taking the time to make this video. And it sounds like you are in the flight path at O'Hare. I live up in the NORTH NORTH burbs.
This video (and the one five years ago) are great for newbies like me to understand how to find the sweet spot for the pilot circuit, but i still have some questions in mind. 1. I have a DRZ400SM, which has a pilot fuel screw on the carb, I installed a jet kit and sized up the pilot jet from 22.5(stock) to 25. I followed your video and found that 1 turn out from closed would be the best setting for it to idle. But my another question would be, how to determine what size of pilot jet to put on the carb? As you have mentioned in the video at 13:30, the AFR would be the same at idle if you can find the correct number of turns on fuel screw, but the AFR at cruise would be different upon changes on pilot jet. So how do I know which pilot jet should be used? 2. Apart from the pilot jet, i have also changed the needle (now its 4th clip from top) and the main jet (sized up from 150 to 160), it seems to be a bit rich as i have tried to take off the side panel of my airbox (in order to increase the air intake) to test and it runs fine with no exhaust popping at deceleration or backfire (sorry this is the only way i know to determine its too lean). So i may try to move up the clip position and go down on the main jet. My question would be, is there any ways to determine which clip position, and size of main jet is the best setting? Besides, how to know if i am running rich on needle and main jet apart from what i have done to increase the air intake to test? I heard there is a tool called Colortune, but i am not sure if it could help to find out the best setting. Sorry for my long questions! As i just installed the jet kit and hope to get the most of it. Thank you!
Do you have a FCR carb on that bike? The pilot fuel screw should be 2-2.5 on an FCR carb, or 2-3 on other carbs. You should install a leaner pilot jet so that you can go from 1 turn out to say 2-3. For needle clip, just experiment with clip positions and your butt dyno with throttle in 1/2 - 3/4 positions.
@@HTMR Mine is a stock Mikuni BSR36 carb. Surly will go back to the stock pilot jet. Like what you said, it will lower the AFR at cruise, but what would be the problem if i stick with the current richer pilot jet? Yup, i understand that the needle affects the 1/2 to 3/4 throttle position while main jet affects from 3/4 to full throttle, are there any signs telling me i am too lean or too rich? Thanks!
@@boblkc You will just consume more fuel. Maybe won't be as crisp? Do some main jet plug chops: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-6b9dMhgZT-c.html
Great video, clears my concept, I need help, sir. I have a 1986 Yamaha YX600 Radian. I am cleaning my bike's carb and I messed up with the pilot screw turns. Initially, before opening my carb I adjusted the screw which operates the throttle position. Now when I adjust the pilot screw how to combine the tuning with the throttle position screw? how does it work together? and which one should I adjust/tune first? Pilot Screw or throttle position screw?
I think that 3 turns out may only apply for CV carbs. The Amal and Mikuni need to be about 1.5 turns. I got an old GP Amal that has the air screw on that engine side. One side effect of running too lean a mixture is that the exhaust pipes can colour up, as happened with my Royal Enfield.
Hay, HOW-TO. You made mentioned the popping sound in your audio. I know what it is. Someplace on that bike, the spark is jumping to the ground. Check the wires and boots.
hi my bike is running rich .plugs are very suity at 3.5 turns out .this sets the fastest idle.would I go down one size with the pilot jet and main jet so it runs a little leaner 🤔
Hi you mention on the fuel screw, pilot jet, if it’s under one turn or maybe under two turns it’s too rich, but that doesn’t make sense as if it’s a fuel pilot screw, the more you turn it out the more fuel your adding, therefore surely if you turn it out for less than one turn, it’s too lean, and not too rich, it will only become richer the more you turn it out.
Hey HTMR, I’m struggling to get a TTR 125 to run with a VM24 swap from Sudco as the original carb was missing from the bike. Currently has 17.5 pilot, 105 main on 3rd needle clip- it will run/idle with choke on only, and when I de-choke it it will rev sharply and then die. I’m trying to get it going for daughter as she has outgrown her KLX110 and I’ve never had this kind of struggle getting a carb to run. I watched your video regarding pilot circuit clogs and the circuit is clear and brand new jet that’s also clear.
@@HTMR Thanks so much for getting back to me and really quickly. I haven’t changed the air screw settings, but I will ensure that it’s set properly before swapping any jets. It will run with the throttle 3/8-full so I’m thinking I need to richen the pilot much like the choke is doing. I merely put in the jets that were recommended on thumper talk thread outlining this swap.
@@HTMR thank you so much. I found the air screw was 5.5 turns out so reset it, fattened up the pilot jet and main, then followed your video on tuning via the air screw instructions and now it has idle without choke, good throttle response. Will continue to fine tune it! At least it will now idle and I can tune it from this point. Hard to do when it wouldn’t even run!
excellent vid great help.could gauges I guess to get the fastest idle,on my old tiumph trident I went from 17 to 19 pilot jets and was surprised on the performance gain as I always thought pilots only really did anything at tiny throttle openings it also got rid off the tiny stumbles it had in traffic,this vid is more applicable to a gs1000g I may be buying but great stuff well done
hello!great work!i have a suzuki freewing xf 650 no exhust (im planninig to install)but open airbox..for sure going faster accelaration and sound but donst work perfecly..i was thinking for some jet kits tuning...please i need your help...thank you in advance 🙂
