Using an O2 Sensor to tune carbs?

I've been looking up O2 sensors and I want to try and use them as a tool to tune the carbs. I am NOT looking to permanently install the sensor but rather the way that I'd do it is that I'd remove the exhaust EXCEPT the headers. I would then take the actual sensor and insert it at the bottom of each of the exposed headers (where it connects to the collector), turn on the bike, and start adjusting. I would only use it for idle purposes NOT for going up and down the rpm power band although I'll most likely experiment.

My first question is, would removing the collector and the mufflers have an effect on the actual air/fuel ratio?

I know that there are for bung holes at the bottom of the header for when Yamaha use to be able to hook up their fancy machines but those holes are not big enough to fit an actual sensor and I don't really want to start drilling additional holes into my exhaust.

This is the product I'm planning on purchasing: https://www.ebay.com/itm/52mm-LED-D...798054?hash=item2644e7c866:g:5okAAOSwLSBfT0Ob

In theory it seems to work and I'm kind of excited but I don't know enough about the science of exhaust and air/fuel ratios and stuff like that. I'm also worried removing the muffler and collector would have an effect on the readings but again, I only want to adjust the carbs at IDLE so maybe removing the muffler and collector would not factor in as much.
Please don't suggest Colortunes. I know all about them thank you very much. Please just stay on this topic.

Looking forward to your thoughts and suggestions.

 

There are sniffer ports in the stock headers.
The use of a probe shoved up the headers comes with the problem of restricting backflow into the header so you don't get a false reading.

You should be able to make a sniffer-type probe from a few fittings and the appropriate size of copper tubing. The trick will be calibrating it to allow for the O2 sensor not being directly in the gas flow. You'll also need to use a heated O2 sensor.

 

http://www.scirocco.org/tech/misc/afgauge/af.html
if you reduce that to a simple test tool all you need is a heated wideband O2 and a volt meter and 12 volts

 

So that link you sent is WAAAAY more complicated then I can understand. I'm just looking for a plug in play simple tool.
How would I make the simple test tool and please, explain it like I'm a 10 year old.

 

So there in lies the question, how do you make a sniffer-type probe?

Also, I don't quite understand your first statement. How would I be restricting backflow exactly? I would not be covering up the headers with the sensor. There would still be an opening for the exhaust to escape. Are you saying just putting that little sensor in there could change things.

 

If it helps, here is a diagram of how I would use it. Please excuse my horrible illustration skills.

 

that's about it but the engine needs to be at running temp and the wires that are going up the header get hot too
mine gave wild swings, all over the place. but i was happy with how it was so i just put it in a box on the shelf
it was a shitz and giggles project

 

I'm confused. Did it work or not?

 

1. A sniffer probe has the sensor in a compartment that is held in the hand, and a length of metal tubing goes into the test port to get the sample.
This is the modern version of what Yamaha was using at the time (but wayyyy smaller). The handpiece illustrates the type of probe that is used with the XJ test ports.
bacharach-fyrite-intech-co-o2-gas-detector-248511.html

2. What you don't want is for the exhaust to exit entirely freely when testing at the exit of the pipes. The exhaust will be dilluted by the bit of air that is sucked back into the header after the exhaust stroke and cause a false reading. That's why onboard O2 sensors are placed well before the muffler.

 

When inserting that probe does it make an air tight seal?? It seems like that would be important but I could be wrong. Unfortunately, that thing is a little out of my price range. I paid less for one of my first bikes.

Being relatively new to bikes I also forgot about the whole 4 stroke thing and realized air would come right back up the header and mess up the readings.

 

The probe only needs a mostly-tight seal. Back in the olden days of car emissions tesing they used similar probes, and a rag to partially block off the exhaust pipe.

 

Good to know. Thanks

 

I might try a little experiment and find some "sacrificial" headers to make an O2 sensor out of them. The idea is to drill a hole into each header right at the first bend coming out of the engine. I would then install the O2 sensor into each header one at a time and be able to ride the bike and see what's happening as I ride it, tuning as I go along. The question is, would the location of the hole I would drill out be too close to the engine. Does that matter?

 

did you get a O2 sensor yet? there's all kinds but the ones i've seen are just too big to do that. the oem pipes are double wall, that won't make it easier.
you could get a digital tach and tune for max rpm and be done

 

I bought a digital cheap Chinese one off of ebay. I don't want to invest too much into this project. If it works, great. Why would the size of the sensor matter? Why does the double wall matter?

 

when i think O2 sensor, it's the size of one that goes in your chevy. i hope yours is way smaller than that. a oem pipe is double wall, so the real pipe is smaller than what you see, a chevy one would come out the other side of the pipe and block half of the pipe. the oem pipes have a bung in them for a yamaha tester but good luck finding one of those.
when it's all hooked up remember that the 14.7 they talk about isn't what you want to run at, needs to be richer or the engine just won't feel right
a link to the tester you have?

 

I see. Well, it was only $40. Here's the one I got: https://www.ebay.com/itm/52mm-LED-Digital-Racing-Air-Fuel-Ratio-Gauge-With-Narrowband-O2-Oxygen-Sensor/164364589569?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

For arguments sake, let's just say it does work. What reading should I have? Is placing it right at the top bend a good spot to drill the hole. Would placing just inside the tailpipe work?

 

i hope it does work out.

no idea but it should be richer than what they call perfect.
the top bend? i would think there might still be fire there, that might not matter but on cars it's farther back....?
maybe put the wires in a pipe (1/2 inch copper water pie) with the sensor attached to the end and push it in the muffler as far as it goes, then read it and pull it out and see how hot it got and go from there.
i seem to remember the heater in mine drew some current so keep a eye on battery voltage
i'm going to put some effort in finding mine.
maybe you want a analog meter that won't bounce as much....?

 

So this thread is a bit of a repeat - did @dkavanagh or @mlew get anywhere after this thread:

https://www.xjbikes.com/forums/threads/exhaust-gas-analyzer-for-tuning-mixture.125471/

 

I've been slacking. I'm waiting on parts for the carbs (have them fully apart this time) and will then need to move the O2 sensor idea along to see how it works.