Using oxygen sensor for carb adjustment.

This is just an idea.
Parts and tools:
o2 sensor nut (bung?) and plug ($5 from ebay)
o2 sensor Bosch 15511 (about $20)
wires
voltmeter (multitester)

1. Drill a hole and weld o2 sensor nut
2.Install o2 sensor, attach wires and voltmeter next to speedometer. 2 wires go to voltmeter, 2 wires to battery for sensor heater.
Any time you will see rich or lean condition. Below 0.45v is lean, over 0.45 is rich.
That would be probably useful for racers.
After you are done, remove sensor and install plug.
If you attach camera to your chest, you can have a video, showing speed, RPM and rich/lean condition

Loudvhx has done it on his 550 using an innovate lc-1. My camaro had an 02 sensor on it for 5 or 6 years too.

Autozone has a $20 simple gauge (narrow band) or the innovate is $120 of so.

Avoid narrow band oxygen sensors for tuning. Only a wideband O2 will give accurate, useful data. I have an AEM Uego gauge I use for tuning cars. I will be using this on my bike when I get it back together. Innovative Motorsports sells a tailpipe adapter that will let you temporarily mount the sensor to the exhaust. You can also get "no weld" bung clamps that make mounting a sensor easy.

I'm amazed that people are still trying to tune carbs by pulling plugs and using their butt dyno.

Narrow band is useless for adjusting carbs because we don't have a computer to change jetting in the carbs continuously which is what old narrow-band-equipped cars do. The lean/rich crossover is too lean for most of what we do on bikes, and is really only for adjusting idle and certain cruise conditions on older cars. The car's computer makes tiny adjustments to the fuel injection system to make the mixture oscillate rich to lean and back. It does this cycle continuously during idle and some cruising.

You need a wideband o2 system to get meaningful data.

By the way, a simple voltmeter does not suffice for any o2 sensor. You need a microcontroller to control the o2 sensor to get proper readings.

JaFlo wrote: ...
I'm amazed that people are still trying to tune carbs by pulling plugs and using their butt dyno.

If time is money, the butt dyno is a huge waste of money. :laugh:

Did that for years. It takes about 10 time longer than using a wideband, and it's never as precise. With a wideband you can really dial in for power AND fuel economy. They can go together nicely.

I got a Harley with Power commander. I adjusted map using O2 sensor and camera mounted on my chest. It took long time, but I did it! Idea was not to pay $400-500 to mechanic with dyno machine.

With the systems we're talking about you just ride around and look at the display, or some people data log it. I prefer seeing in real time, so I like the analog gauge because I don't have to look right at it to see what's happening (have to keep one eye on the road).

My brothers use to tune each carb to each cylinder .
If using a sensor after the merge then that not really tuning each carb.
I look at each plug and then riching or lean it accordingly . Then check temp at each cylinder.

You could mount a bung on each header tube to tune the carbs individually, but a good set of synchronized carbs should be very close in AFR at any given time. Reading plugs will never be as accurate as a wideband O2 reading, although there are some people who are damn good at it.

It should be noted that the secondary air system should be eliminated or temporarily blocked off before using an O2 sensor to tune.

spdygon wrote: My brothers use to tune each carb to each cylinder .
If using a sensor after the merge then that not really tuning each carb.
I look at each plug and then riching or lean it accordingly . Then check temp at each cylinder.

I guess you are talking about idle speed mix adjustment, right? It kind of makes sense to run engine at idle, then look at spark plugs. It is not that easy because you have to "unchoke" on time or plugs will get black just because you kept choke on longer than you should have. Or you can warm up motor, then clean plugs and run them at idle.
Please explain how you adjust carb checking spark plugs and temperature. Where do you read temperature? Close to spark plug?
Thanks. I like how you do it, it seems to be a smart way to adjust carbs.

Yes, if you are only using one sensor, you have to really be sure all cyclinders are same, and all carbs are the same. Generally, if there is a problem with one cylinder, the plugs will show it or a ifrared thermometer will show a significant temp diff on the header pipe. (You can get a no-touch infrared therm. for dirt cheap nowadays.)