Probing question

[Huzo]

The probe thing on the headers of my V85..
How critical is the location with respect to distance from the exhaust port ?

[pat80flh]

Oxygen sensor?  I'd say it was fairly critical. On automotive systems, there is a sensor after the catalytic converter which is only  used to measure catalyst efficiency.   A threaded bung about 2 inches long would move the sensor away, reduce the amount of exhaust gas sampled, and fool the computer into believing the catalyst was ok.

[s1120]

Its important.... Too a point. There is a big fudge factor to work with though.  On cars it is pretty common to move sensors around with no ill effect at all. Ive moved them from right near the heads, to lower on header collectors, and Y pipes with no effect. [or at least in the range that the computer could make up for it.]  Those headpipes are really so short, I would not worry about moving it anywhere on them. What are your plans?

[Kev m]

O2 sensors need a certain temperature range to operate. They don't read useful data until they are heated sufficiently.

That was the original reason they were placed so close to exhaust ports.

These days they contain heater elements which help them come up to temperature faster. Now I'm not sure if the heater circuits remain on after warmup and/or if the sensor location helps maintain that temperature once warmed, but it could be important still.

[Xlratr]

I think anywhere on the header should be ok. But orientation is important. The outside part should point "upwards" somewhere between 10:00 and 02:00. Something to do with condensation or other stuff not falling on to the sensitive part of the sensor.
That's what I remember reading when I was messing around with wide band sensors on the Stelvio.

[Huzo]

What are your plans?

The bike has an Agostini Y pipe, the cat converter has been removed.
As you can see, I do not use the header guards and bash plate. The waisted section where the probe is looks crummy so he headers are leaving...
New mandrel bent stainless ones are coming to complement the Agostini pipe. I have to install the probe.
So I am clear on this, is that the O2 sensor, or does it measure all manner of gases ?

[Waterbottle]

Hi Huzo, I've been doing a bit of data logging on the track Griso using Innovate Motorsports equipment. this is an extract on advice mounting the O2 sensors . Cheers Ron
2 Air/Fuel Ratio Setup
2.1 Sensor Placement
Optimum bung placement will vary from application to application, but using
the guideline below will ensure the longest sensor life with the most accurate
readings. Using a bung is the preferred method for mounting the oxygen
sensor in all applications.
 Weld the bung at least 24 inches downstream of the exhaust port outlet
(after the collector), or 24 inches after the turbocharger if so equipped.
The bung should be welded before the X or H pipe if so equipped.
 Using a clock as reference, mount the bung between the 9:00 o’clock
and 3:00 o’clock position. Welding the bung in the lower section of the
exhaust pipe can result in sensor damage caused by condensation
making contact with the sensor’s internal heating element.
 A 1” bung (provided in the kit) will best protect the sensor. When fully
threaded, the sensor’s tip will sit flush with the exhaust pipe, this does
not adversely affect the readings.
 The bung should always be welded before the Catalytic Converter.
Welding the bung after the catalytic converter will skew the readings
toward lean. The skew in readings will vary with engine load and the
efficiency of the catalytic converter.

[Huzo]

Hi Huzo, I've been doing a bit of data logging on the track Griso using Innovate Motorsports equipment. this is an extract on advice mounting the O2 sensors . Cheers Ron
2 Air/Fuel Ratio Setup
2.1 Sensor Placement
Optimum bung placement will vary from application to application, but using
the guideline below will ensure the longest sensor life with the most accurate
readings. Using a bung is the preferred method for mounting the oxygen
sensor in all applications.
 Weld the bung at least 24 inches downstream of the exhaust port outlet
(after the collector), or 24 inches after the turbocharger if so equipped.
The bung should be welded before the X or H pipe if so equipped.
 Using a clock as reference, mount the bung between the 9:00 o’clock
and 3:00 o’clock position. Welding the bung in the lower section of the
exhaust pipe can result in sensor damage caused by condensation
making contact with the sensor’s internal heating element.
 A 1” bung (provided in the kit) will best protect the sensor. When fully
threaded, the sensor’s tip will sit flush with the exhaust pipe, this does
not adversely affect the readings.
 The bung should always be welded before the Catalytic Converter.
Welding the bung after the catalytic converter will skew the readings
toward lean. The skew in readings will vary with engine load and the
efficiency of the catalytic converter.

Thank you Waterbottle..
That is nice and definitive. Just a question so I’m up to speed a bit more.
The sensor is less than 24” from the exhaust port as standard, do you see that as problematic ?
Also.
With reference to the comment regarding orientation of the sensor, can I therefore mount my sensor(s) so they point inwards towards each other to some degree as long as they are not horizontal ? I would like to have them as difficult to see at a glance from side on, as I can achieve.

[Waterbottle]

Huzo,
I don't think you will have a problem mounting it closer than the 24 inches, the advice they have given is assuming you are mounting a sensor in a motor vehicle, where mounting upside-down could cause condensation problems. Also the amount of heat generated by 1 cylinder as opposed to an 8 cylinder or turbo charged engine is minimal. So long as it's not hanging down you should be fine. Horizontal ( In a car's exhaust under the vehicle ), is 9 o'clock  or 3 o'clock )

[Huzo]

Huzo,
I don't think you will have a problem mounting it closer than the 24 inches, the advice they have given is assuming you are mounting a sensor in a motor vehicle, where mounting upside-down could cause condensation problems. Also the amount of heat generated by 1 cylinder as opposed to an 8 cylinder or turbo charged engine is minimal. So long as it's not hanging down you should be fine. Horizontal ( In a car's exhaust under the vehicle ), is 9 o'clock  or 3 o'clock )

Thank you mate.
You should mount one on your roof to check the air quality re bushfires...

[Waterbottle]

Yeah the fires are getting tiresome
This is where i mounted them on the race bike, just in front of the gear lever.

[beetle]

What Ron (waterbottle) said.

Do not install the sensor closer than 6 inches to the exhaust port.
The sensor only senses oxygen.
The heaters in the sensors are active at all times the key is "on" on the CARC bikes, so assume the same for the V85.

[Kiwi_Roy]

A little background on how the Zirconia probe works.
https://www.sstsensing.com/zirconia-oxygen-sensor-function/

[Huzo]

What Ron (waterbottle) said.

Do not install the sensor closer than 6 inches to the exhaust port.
The sensor only senses oxygen.
The heaters in the sensors are active at all times the key is "on" on the CARC bikes, so assume the same for the V85.

Ok thank you .
That advice is locked in..

[lazlokovacs]

I asked PaulDaytona the exact same question a few years back

As I recall, he advised having the probe about exactly where your one currently is, maybe a bit further back but definitely no closer!

[Huzo]

I asked PaulDaytona the exact same question a few years back

As I recall, he advised having the probe about exactly where your one currently is, maybe a bit further back but definitely no closer!

Ok mate, thank you also.
That is welcome news.