Tuning Carburetors using an Oxygen Sensor - The better way.
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- เผยแพร่เมื่อ 6 ส.ค. 2021
- I show how I tune the carbs on my motorcycle using a wide-band oxygen sensor. It works out great, too. To do this, you'll need a wide-band o2 sensor and you'll need oxygen sensor bungs on your exhaust. The latter will require welding. Video doesn't cover that but here's a good TH-cam video that does: • How to Install a Weld ...
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You have justified the fact that I may not be able to eat till next pay check, but I will feel so happy knowing I'm not melting my engine! I have an 81 CB650 with 4 carbs, that I recently "upgraded" to 2, Mikuni VM34's, that I also hace a double 2 to 1 exhaust, so I will be welding in 2 O2 sensors, and tuning per side!
Hardest part is putting the bungs into the header! Awsome video!! Gives me inspiration!!
Oh, my god, that´s really amazing. That sound is very fine after de adjustment
Robert - bugging you for some help, again sir. :) I picked up a MotionPro carb sync tool. Last weekend, had it all set up to calibrate but apparently my idle RPM was too high. Two second later, poof all the fluid was gone. So, they sent me some more. Got the tool rebuilt. Planned to do that today. Now... side note. I have one of the TrailTech Vapor gauges (752). My tach has never read correctly - typically sporadic, and too high. It's an inductive wire, they basically tell you to wrap it around a sparkplug lead and tape it. So that's how it was for five years. I emailed them the other day, to see if there was a more accurate option, since it would help to not run into the same issue with the manometer. Chatted with a tech, and showed him the wiring diagram from the forum. He suggested either the orange or grey wire, running from the ignition coil. So, I wrapped the tach wire around the orange wire spade terminal, and started the bike. Gauge went bananas - lights blinking all over, but it did start. Monkeyed with the idle a bit, got the manometer ready to go.
Then the bike wouldn't start. I hadn't had it hooked up to my trickle charger for a few days, however it had just turned over several times with no issue. Now it was making a quick turnover "click", then all the power cut out. I hooked up the trickle charger and went to bed. Went back out about an hour ago. Said it was charged, but same symptom. I tried connecting my DieHard AC charger and let it sit for a couple min. It said charged - turn the key on, the needle drops but the headlight looks fine. Until turning it over. I would think it's just a dead battery but the timing seems too coincidental. Also, today I noticed that as I try to start it, I see some wisps of smoke coming off of the battery area somewhere. The positive lead also feels hot to the touch (I don't know if that's normal).
Shot a quick video. You'll notice it did try to turn over once, but that's the only time that happened. I'm really not convinced it's the battery... I'm wondering if something shorted out. I checked the fuses, they're fine. Not really sure what else I can test.
th-cam.com/video/iWDH5m2sxig/w-d-xo.html
Thoughts? Thanks - and sorry for the lengthy description!
This is really cool. I've just gotten into messing with my klr650 and I'm constantly worried I'm running too rich or too lean. Thanks!
I need to get me one of those sensors, no more counting turns!
Perfect! My bike is a 350 single and the carb wasn't yamaha's finest work. I started wondering how easy this would be to do since I have the same gauge in my car for tuning. Looks like the hardest part will be welding in the bung.
Perfect. I am currently trying the same thing because this carb is not stock and it’s a little oversized so I’m trying to tune it. I’m honestly amazed I had it running at all. It was at 20:1 ratio. I pulled choke to make sure gauge was working and it went down to 12.6:1 and I was amazed it was that bad. Im about to rejet the whole thing and see what I get. Shop said small jets because it’s smaller displacement motor but that has been wrong for this style carb so far.
Whoa! 20:1 is crazy. Small jets, small bike thing doesn't make sense to me. Good luck with the rejet!
I have a spare aem wideband and also plan to do some tuning I have a GL1000 and an old Matchless 500 , that's got a bigger panther amal carb on it , I will be mounting it on the bike for a ride to check each part of the range .should be fun .
Very cool!
Oh yeah… great video, thanks.
Nice work, do you have wiring how to link gauge 3p to oxygen sensor?
very good! Thank you for sharing wisdom
Of course. Glad you enjoy it!
I put a Wideband O2 sensor on my 77 kz1000, but just one bung in the 4-1 collector pipe. Now, I have a cylinder with good spark and compression that is down 200 degrees cooler than the other 3. Looks like I'll be welding in bungs in all 4 cylinders and working each carb individually. I tuned the carbs until I got my AFR gauge in the 12.5 to 14, depending on accel/decel/idle and was happy with it, until the temp gun showed me the huge difference in one cylinder. Damn. I have to careful with my $900 Kerker pipe, no room for error welding on these additional 4 bungs.
Good luck with the bungs. I've screwed up a couple headers by either cutting them off-center or putting them in the wrong location so they hit the frame. Are those headers stainless?
@@RobertAdairWorkshop roasted
Replace the pilot jets with all new pilot jets. Go buy new ones, throw the old ones away. Problem solved. It's the pilot jets which get tiny invisible chunks of grit in them, and they can't be cleaned properly, because cleaning the tiny almost micro holes, damages the metal and ruins the jetting. Just buy new ones.
Hey Robert.
Great video but I have a few questions mainly about the install.
Where do I get the bungs for my specific bike?
How are they installed? I'm assuming you take your bike in to a shop that can drill and weld them in place, if you have no welding tools/skills right?.
When they're not being used are they pluged with a regular bolt? does that come in a kit also? any gasket required?
Can't find any videos on this.
Thanks
I usually buy the bungs on eBay. They come with the round bung and a plug. The plug protects the threads and seals the hole when you're not using an O2 sensor. No gasket required, just anti-seize. Here's an eBay link for the ones I used (unaffiliated): www.ebay.com/itm/401630796546 . If you search eBay for "Oxygen Sensor Bung", you'll fund hundreds of them. I went with the low profile ones since I didn't have a ton of space around the exhaust.
They are installed by drilling a hole in the pipe and welding them in place. Here's a youtube video that shows how they are installed, with great detail. th-cam.com/video/thssdk7TtsY/w-d-xo.html
If you don't have the tools, you might be able to take it to your local motorcycle shop and have them do it. That or maybe a muffler shop?! You'll likely have to tell them what where to install it on the pipe. Someone who can weld should be able to do it but I'm not sure how you'd find that person. If you're in Denver, I'll do it for you.
Just a dumb question, but did you not totally destroy the exhaust headers by welding bungs on there? I have a ZZR600 and I'm nervous to weld anything onto the stock header pipes.
I didn't destroy them. I used a hole saw the right size and welded the bungs in. But my bike originally had painted headers. I should point out that I don't run the headers with the bungs anymore. I bought a pair of Deklevic stainless headers for the bike and install the old pipes with the bungs only when I need to check the a/f. That could be an option for you depending on how hard those ZZR600 headers are to swap.
Macam mana pasang
good job
Thank you, Lanc Mac.
What when you don't have these holes in the exhaust? How you can measure?
You won't be able to. You need a place to install the sensor.
Hi Rob. Great video. I’m in a similar situation. I have a CB750 with non stock carbs and this seems to be the most straight forward approach to measuring the AFR. Do you have a #pn for the aem gauge ? There seems to be a few similar. Cheers
it’s the UEGO 30-4110.
Well that's clever.
Please help me sir,
Is your afr sensor universal or the same thing people using for ECU bikes? or this afr sensor is made for carbureted bikes?
also gonna be use in carb bikes, do i just have turn it on and plug the o2 sensor in elbows|? thank you!
This is a universal wide-band oxygen sensor. It works with any type vehicle, carbureted or fuel injected. If you have the bung on your exhaust, you can screw it in and turn it on. But all it'll do is tell you the air/fuel ratio.
Robert, great video. Would love to see some numbers as you go down the road in midrange (to check needle position) and then wide open (to check main jetting). Otherwise, this is a great video for familiarity with this process!
Hey, Donovan. That's a great idea. I don't think I've ever taken the setup out for a ride. I could hop on it, point the camera at the gauge and give it a shot.
@@RobertAdairWorkshop If your gauge has an analogue output, you can run a data-logger.
@@stuwy1237 I don't know if it does. I'll take a look. That's a really good idea.
do you have the purchase link to the specific model of the AEM o2 sensor kit?
The one I have is probably 15 years old. Here's a very similar one: www.summitracing.com/parts/avm-30-4110
Where did you buy everything from? And can I ask why aren’t you doing mains first? if you do mains after pilots you’re back to square one again ?
Everything from eBay, but years ago. Mains were already done a few years ago, and were spot on. This was after a disassembly and cleaning, to set the pilot screws after removing them for cleaning.
Big difference
Oh damn this is a Xj600 :D
I am ön tuningolt the carbs but the gunson plug isn't that great :/
What AFR you have at constant speed riding? I have a old R6 with carbs and it runs very rich in this condition. I think pilot jets are worn or floater height didn't fit anymore.
I've never done a run with it with the AFR attached. Mostly because the sensor hangs down. But I can get out on it and see where it sits at cruising speed and get back to you.
@@RobertAdairWorkshop would be nice to know. I have a AEm failsafe wideband - this can datalog and I won't have to look everytime on the display.
Is that 14 reading a universal goal for all bikes? I have a single cylinder 250cc 4 stroke dual spot I want to tune, but it's hard to find information on this topic at the moment.
Thanks for your help!
Yeah, its the same for any 4-stroke normal-burn engine. 14.1 is stoich.
@@RobertAdairWorkshop There's a lot of information I'm trying to take in here, and not a whole lot of resources that make a whole lot of sense to someone as newby as I am. But I'm starting to get the hang of it.
All this headache still is better than the idea of tuning it "by ear" and having to just more or less guess what's good and bad.
Robert, does it matter where I install the bung on my exhaust for the sensor to pick up a reading?
I have them about 14" pipe length from the cylinder head. I think I read somewhere that you needed the exhaust gasses a certain temperature but that could have been for non-heated sensors. I'd guess anywhere from 8 to 18" along the pipe from the head should work. Make sure that wherever you put it, that it only reads one cylinder.
@Robert Adair aaah okay. Can you please do me a favor and go to my TH-cam channel and see my 1994 Fatboy (10 November) and tell me what you think of the crossover pipe that's connects both cylinders (exhaust gas wise). Not sure if you would recommend the O2 sensor being before it or not. I can't thank you enough for helping me. I don't have anyone else that I can trust
it was litle beter if can se how connekt the sensor
Hey man new subscriber here, I know its been a while since you made this video. But I'm kinda curious how much does a 1/4 turn on the pilot screw affect the numbers on the Guage? Thanks
It's one of those "it depends" sort of things. On my bike, the total effective range of the screw is about 2 1/2 turns. That is, I can only turn the screw 2 1/2 turns and have it do anything. Any more than that and I have to swap jets. So in that case, 1/4 turn could make a big difference. But some carbs have screws with a large range and 1/4 turn isn't much. But back to my bike, 1/4 turn of the screws moves the A/F roughly 1-point. I.e, going from 12.1 to 13.1 or going from 15.1 to 16.1. Not a great answer but hope it helps a bit.
@@RobertAdairWorkshop thanks for the reply, that totally helps a lot. Im trying to get my bike a little lean for fuel efficiency since im only using it for work.
saw a video here on TH-cam that tried around 16:1 ratio and it actually did a little worse mpg compared to the ideal 14.7 afr, turns out you need to advance the spark timing in order to see positive results since a leaner afr burns slower.
I'm trying to achieve an afr close to 15.3 cause he found out that it's the leanest afr you can get without having to adjust the timing and have positive results
Anyways my pilot screw have more effective range, so im guessing a 1/4 turn could probably raise my afr by .5
Thanks again
Thank you
You're welcome
Good info
Thanks
AMAZING JOB!!! THANKS FOR SHARING!!!! I'm glad I stumbled upon this as I am an old school tuner and have recently been given some advice on tuning a Harley-Davidson. The vehicle doesn't have any accommodations for an 02 sensor so I'll probably have to have some installed. Is there a recommended placement location required for better accuracy? Since i have only one carb (and 2 cylinders) i gather id only need one bung installed on one of my pipes or would you recommend 2 even though they share one common carburetor?
Thank you
Hi, Kenneth. I've not owned a Harley. I'm not sure how they fuel. I think its one carb for both cylinders, right? If that's the case, you ought to be able to get away with one o2 bung. Does the rear cylinder run hot on those? If so, I'd put it on that pipe as it will be the one that runs more lean than the other and would give you a safer setting.
@Robert Adair yeah, one carb feeds both cylinders and yes the rear does get hotter so I'm going to try going with the rear one. Thanks for the response
@@RobertAdairWorkshop I saw somewhere that 6" downstream of the head is preferred for installation of a bung. What size bung is commonly used for this?
Why can’t you just… chuck the sensor up the tailpipe?
@@drewmanzara5731that's what I'm thinking
so you only do the test for idle? what if your main jet is way off at full throttle? do you let it warm up before taking the readings? many questions
There’s no reason you couldn’t take it out and do full throttle pulls and then set main jets accordingly. I just never got around to it. Do the tests with the engine warm and a fan blowing at the front of the engine to help keep it cool.
Should be doing mains first
so when you have to start with choke do you let it warm up then turn off the choke and then do the tuning?
You want it to be at operating temperature before you tune it. Fan in front of the engine to keep air flow. No choke.
@@RobertAdairWorkshop ok I got the idle jet tuned today.sits get stable at 13.6. thanks for the help
@@warrenpeas That’s good news.
I missed the explanation. Where are you inserting the sensor
The sensor threads into O2 bungs that I welded in each of the four pipes.
Great video! How's your AEM gauge working? I saw all the reviews on amazon saying that the sensor fails all the time. Is yours still working and is it a BOSCH sensor or just generic?
Thanks! Mine is still working as it should. I’m using the Bosch sensor that came with it. It doesn’t get a lot of use. Maybe only 10 hours or so since I got it so I’m not really sure about reliability. But I’ve had mine for 10 years or so.
@@RobertAdairWorkshop Thats good I think their quality is not as good as when you got it. A lot of people have been reporting getting generic non BOSCH sensors with the AEM kit that fail out of the box.
youve only tuned the idle so far I i would like to see you ride it down the road to see your afr at half throttle and wide open throttle
@@fatbob785 sound like a good idea for a follow up video once it warms up a bit outside.
@@RobertAdairWorkshop I plan to do the same on my little honda monkey bike, I've set the idle afr at 13.5 ,now want to take the bike for a run to see what the afr is throughout the rev range and wide open, but that will have to wait for a dry , salt free day lol
Would it be possible, & effective, to simply slide the sensor into each of the 4 exhausts through the 4 into 1 collector, with the muffler removed?
You’d have to get it in far enough that air didn’t circulate back in and mix with the exhaust. That would skew your readings. But should be doable if you can find a way to hold them in place..
@@RobertAdairWorkshop thanks
Hey Robert, I’ve got a O2 sensor & gauge on the way now, & after advice from that supplier I’m going for 4 separate bungs as you did.
Do you see any need to balance carbs after setting the mixtures?
Sorry, another query also……..re jet sizes……. I’m assuming that if you run out of adjustment at either end of the mixture screw, then you either need to downsize or increase your idle jets?? And if you increase your idle jets by say, 1 size, should you automatically increase the main jets too? Thanks 🙏🏻
@@murraydeeth7834 That's how I've always done it. On my XJ, which is the bike in the video, the screws vary from 1/4 turn out to 6 turns out. I've taken apart factory-set carbs with screws in this range. I'd think if you found a screw that was all the way in, or way-way out, changing pilot jet size would be the way to go.
How do you test the main jet circuit?
You can use the same gauge for the main circuit. You'll need to be moving so you'll have to take the bike out for a ride. Main jets, I think, are 3/4 to full throttle. Run wide open for a few seconds and watch the gauge to see how it performs. Main jet adjustment would need to be done by replacing jets.
@@RobertAdairWorkshop perfect thank you for your reply
@@RobertAdairWorkshop would you be looking for ~ 14-1 range across the board on all throttle inputs ?
Can you share the brand/model so I can search for it? Your video seems very useful to tune carbs by myself, where I live all garages say they tune carbs "by ear" (since I live in Spain this is the literal translation of "de oído", don't know the correspondence in English) and that is not a very scientific method, I prefer yours.
Hey, Manuel. It’s an AEM UEGO wideband model 30-4110.
www.aemelectronics.com/products/gauges/wideband-uego-air-fuel-gauges/digital-wideband-uego-afr-gauge/digital-wideband-uego-afr-gauge
@@RobertAdairWorkshop Found it at 229$/€, it's expensive for me although it should worth the price. Also found a lot of cheaper (and unbranded) options along the internet...
Why did you choose this model?
Would it be possible to find some cheaper alternative?
Maybe buying a spare Bosch LSU sensor and a compatible gauge?
@@gallegoenlaluna I bought it 12 years ago, I think. Not a lot of unbranded options available then as the technology was pretty new. If I were getting one today, I'd go with a cheap one.
@@RobertAdairWorkshop I have realized that my bike has four M5 threads, one at the bottom of every manifold, that I think were used to connect EGT sensors for measuring exhaust gas temperature :( Maybe Yamaha used to tune the bikes that way but I don't know if that is a good alternative to the AFR sensor.
I'd like to find a reference temperature value so I would buy some EGT sensor and try to tune the bike this way, but I don't know where to ask/find it. Doesn't it seem the kind of data that can only be found at a Yamaha factory?
@@gallegoenlaluna That's a really good idea. I wasn't able to find a number in any of the factory manuals I have, either. I thought about trying to calculate it and then realized that the temperature is measured quite far from the head. Maybe test each of the four, set them to an average and see how it runs, then go from there and try to dial in an ideal EGT?
this is so fucking great to bad you did not show it how was done. But the tune part so great.
Can you just stick the sensor into the exhaust pipe? Do you need the bung?
If you have a single cylinder engine, that should work. Multiple cylinders, and you won't know how the tuning affects each specific cylinder, just the engine as a whole.
@@RobertAdairWorkshop I have a V twin with separate headers where I can put it in each one and see ?
@@TheHavoc09 Should work. Put it in about 12" if you can. The further into the pipe, the better. If too close to the end of the pipe, it'll report leaner than it really is.
Perfect! Thanks for the video and the help! 😊
Can i tuning my motorcycle with a narrow band sensor?
I tried that several years ago and it worked, almost, at-leas for setting at idle. The problem was that you had to be really close to stoich or the meter would peg, one side.
@@RobertAdairWorkshop I just need to know my engine don't working too lean or too rich & combined with the color of the spark plugs, thank you!
Narrow band is not recommended and is mostly used for an ecu to pass/fail check. Wide band tells you what ratio you are running, which is much better for any sort of tuning.
Your lambda sensor is installed wrong, it has to be 10 degs min from horizontal,otherwise it will soon get contaminated with condensation,making all measurements superfluas. Also,surely you can have the sensor mounted after the collector,so you dont have to move the lambder sensor everytime.
It wasn't a problem. It's heated. No way any condensation would remain on it. If I mounted it after the collector, I wouldn't get individual carburetor readings. I'd have to try and tune one carb based on the A/F ratio of two. Remember, it's a motorcycle with four carburetors, one per cylinder. If I'd installed it in the collector, it'd been mute and I'd have been just as well off as if I hadn't used the A/F gauge at all.