CAUTION: O2 Sensor Advice

[sansnombre]

After putting on my Yosh exhaust system and following the advise to remove the O2 sensor, I simply wrapped it up in some extra thick plastic, rubber band it, and zip-tied it under the right side cover panel. Thought I was good to go, but I did notice that it seemed a smidge rich in sound and throttle response, but thought it couldn't be - there's no mechanism for it to get too rich, slightly richer, yes, but nothing more.
So a few rides later, I'm still thinking it actually does feel rich, esp after full warm-up, it seems a little sloppy on on/off throttle response. Not super bad, but disappointing. Because I was installing some other intake mods, I didn't really care as I was going to get rid of the problem anyway. Getting ready for the other mods, I was watching a Russian Rider vid, and saw that he [em]disconnected[/em] the O2 sensor at the electrical junction under the same panel, and it got me to thinking - I just removed the sensor but did not disconnect it. Which led to thoughts of how those sensors work, and if I'm not mistaken, a small current is run through a filament, yadda yadda yadda. So I checked the sensor, and the plastic had all melted!!
Essentially I left the sensor "on" by not disconnecting at the clip and who knows what kind of signal it was providing to the system? I was able to get the plastic of and it doesn't appear to be damaged. Needless to say, I disconnected the clip and removed the sensor completely from the bike.
I can't comment on the change in fuel mixture by disconnecting the sensor, as I added the EJK and a K&N filter at this same time. But with the new filter, removal of the snorkel, and adding the EJK, the bikes throttle response is great. No hang ups on returning to idle, very responsive to input, and the sound is perfect, as far as lean/rich sounds go.
I haven't taken it out for a good ride yet since installing the new parts, but will update as I do.
BOTTOM LINE: DISCONNECT THE O2 SENSOR, DON'T JUST REMOVE IT FROM THE PIPE.

[RobMoore]

uhhh, what did you screw in where the sensor was?

[aeisan]

Yo... That is NOT what the advice was intended to suggest you do. I hope no one ever told you to do that.  
 
You can do one of two things... Either leave the sensor in place and disconnect it at the electrical connector or remove and disconnect it then plug the sensor bung on the pipe with a cap. Never in a million years would I remove the sensor from the bung AND keep it connected. That's just bad news.
 
Also, same question as Rob... What did you do with the bung? Did you cap it or leave it open? Hope you capped it at least.

[xdr]

Does the Yosh have an o2 bung? My guess is that it does not, and that is the reason the o2 sensor was not installed.

[RobMoore]

it does

[sansnombre]

No, this just was bonehead move on my part. I had read a few times to "remove the sensor" and didn't give it any additional thought. After installing the pipe, I didn't reattach the O2 sensor, packaged it up and put it out of harms way. The video cued me to finally think about it, and once I did, I realized I F'd up and needed to take a look, and sure enough I made a mistake. The original port ("bung") in the pipe was sealed with a screw, an M12-1.25, if I recall correctly.

[Beemer]

My AK carbon pipe came with a plug and I took the 02 sensor out and installed it but next I had trouble disconnecting the wires. (I wanted to remove the whole sha-bang) I tried wrapping up the length of wire, the sensor and putting it all behind the side plate but it wouldn't fit so I called Dobeck and the gentleman I talked told me the trick to disconnecting the wire but went on to say that the EJK overrides the sensor at 1500 rpm so leaving the sensor in AND connected shouldn't affect the bikes performance. Just putting that out there in case anyone else starts to have an unnecessary delema.

[sansnombre]

Interesting about Dobeck - I've seen their posts that say the two components (O2 sensor and EJK) are basically each trying to push the flow to different levels, and since they're battling, it's best to remove the O2 sensor. In the end, perhaps the EJK wins, and it's ok to leave it attached, but it seems that to remove it is probably the best bet, esp if you are not using the EJK, as removing the O2 sensor tends to richen the flow a little at low throttle and idle.

[tuninghq]

I think I can provide some clarification to this situation.
 
The bike seems to run rich and plastic was melted to the O2 sensor
 
This is a mistake I have seen a few people make. They remove the O2 sensor, but do not disconnect it. This is basically putting your O2 sensor into open air. An O2 sensor measures how much air compared to fuel is in the exhaust gas. This provides an air/fuel ratio (AFR) reading to the ECU so it can maintain a emissions compliant AFR under low rpm and steady cruise conditions. Because the O2 was reading nothing but air and no fuel, it was getting an extremely lean reading and added fuel to compensate for it. That is why the bike seemed overly rich. The plastic melted because the O2 sensor has a heater circuit to get the O2 sensor up to operating temp before taking a reading.
We absolutely recommend plugging the bung if you remove the O2 sensor. This would be a major exhaust leak if it is not plugged up.
 
"EJK overrides the sensor at 1500 rpm so leaving the sensor in AND connected shouldn't affect the bikes performance."
Your stock O2 sensor controls the fueling below a certain rpm; When an O2 sensor is controlling the fueling based off of a O2 sensor reading, this is referred to as a closed loop system. If the fueling is a set amount of fuel not based off an O2 reading, then this is referred to as an open loop system. Most fuel controllers give your bike an open loop tune up as they are not using an O2 sensor to control the fuel.
 
Our EJK does not override the sensor at 1500 rpm, we simply start controlling the fueling at 1500 rpm as the fueling at idle is good. In this scenario, the O2 sensor is disconnected.
If the O2 sensor is connected and closed looping, then we cannot control the fueling as any fuel changes we make will be corrected and returned to emissions compliant fueling by the O2 sensor.
 
However, your stock O2 sensor does not control the fueling throughout the entire rpm range, only at low rpms and steady cruise as this is the area the EPA wants to control because this is the range where the majority of riding is done. Once you reach a certain rpm or load on the motor during hard acceleration, the O2 sensor switches off and the bike goes into an open loop fueling. If you have the O2 sensor connected and the EJK installed, we would be able to control the fueling once the bike switches to the open loop map.
 
We only recommend leaving your O2 sensor connected if you want to be street legal (especially in California) or if fuel economy is important to you. The stock O2 sensor targets a lean AFR of about 14.7 to meet emissions; leaner usually means better fuel economy, but less performance. If you leave the O2 sensor connected, you will still have good performance in the higher RPM range or under heavy load. I apologize if I did not make that clear.
 
We recommend disconnecting the O2 sensor (whether leaving it in the exhaust or removing it completely) as it seemed to help riders with the abrupt decel (upgrading the forks will also help cope with the abrupt decel as the stock suspension was left pretty basic). If you choose to disconnect the O2 sensor, but would still like to maintain some fuel economy, then we recommend reducing the setting in the green zone until you like the fuel economy.
The Green fuel zone correlates to low rpm and light load cruising conditions.
 
So in the end, with the O2 sensor connected the EJK does not win the battle under low rpm and light load cruising conditions. We can only start to control the fueling once the bike drops into the open loop fueling.
 
Let me know if there are any other questions concerning the O2 sensor and EJK.
 
-TuningHQ

[pattonme]

@tuninghq could you put similar verbiage in your vendor area where you describe your product? Maybe you have, but the above was very useful.

[00RAH]

Open question to anyone: is your o2 sensor connected? any noticeable difference when its disconnected?

Edited November 29, 2021 by 00RAH

[mjh937]

I have mine disconnected.  I had occasional “surging” and disconnecting it cured that.  I have a flashed ECU which I love.  I do not know if the flashing was responsible for the surging or not but I would not go back to the stock ECU program.  

[00RAH]

why did you put surging in commas the first time but not the second? i like that you love your ECU.

[mjh937]

18 minutes ago, 00RAH said:

why did you put surging in commas the first time but not the second? i like that you love your ECU.

I am not sure, I guess the quotation marks were not really necessary.  Also my fuel economy did not seem to be affected by disconnecting the O2 sensor but perhaps it would make a difference with a stock tune. 

[Taipan]

On 11/29/2021 at 10:50 AM, 00RAH said:

Open question to anyone: is your o2 sensor connected? any noticeable difference when its disconnected?

Do those electrical connector plugs actually do anything, or  are they just a sealing plug for the connector?

[00RAH]

i just found this on ebay. thats the back of the plug idk what it would do ...

[nozeitgeist1800]

On 11/29/2021 at 4:50 AM, 00RAH said:

Open question to anyone: is your o2 sensor connected? any noticeable difference when its disconnected?

are you talking only people with yoshis? i have an akra ti, with the o2 sensor plugged in (per 2wdw advice). no clue if there is a change if it is unplugged, though, too sissy to do things not in the instructions when it comes to this bike lol

[Taipan]

I installed one of those eBay o2 sensor eliminator and I did notice on small, or trilling. throttle openings it reach slightly higher revs, so I assumed was fattening up the closed loop in some way? But it also made a quite substantial drop in (imperial MPG) economy. The reward wasn't worth the cost for me, so it came back off again.

 

[klx678]

On 9/14/2015 at 5:25 PM, tuninghq said:

I think I can provide some clarification to this situation.
 
The bike seems to run rich and plastic was melted to the O2 sensor
 
This is a mistake I have seen a few people make. They remove the O2 sensor, but do not disconnect it. This is basically putting your O2 sensor into open air. An O2 sensor measures how much air compared to fuel is in the exhaust gas. This provides an air/fuel ratio (AFR) reading to the ECU so it can maintain a emissions compliant AFR under low rpm and steady cruise conditions. Because the O2 was reading nothing but air and no fuel, it was getting an extremely lean reading and added fuel to compensate for it. That is why the bike seemed overly rich. The plastic melted because the O2 sensor has a heater circuit to get the O2 sensor up to operating temp before taking a reading.
We absolutely recommend plugging the bung if you remove the O2 sensor. This would be a major exhaust leak if it is not plugged up.
 
"EJK overrides the sensor at 1500 rpm so leaving the sensor in AND connected shouldn't affect the bikes performance."
Your stock O2 sensor controls the fueling below a certain rpm; When an O2 sensor is controlling the fueling based off of a O2 sensor reading, this is referred to as a closed loop system. If the fueling is a set amount of fuel not based off an O2 reading, then this is referred to as an open loop system. Most fuel controllers give your bike an open loop tune up as they are not using an O2 sensor to control the fuel.
 
Our EJK does not override the sensor at 1500 rpm, we simply start controlling the fueling at 1500 rpm as the fueling at idle is good. In this scenario, the O2 sensor is disconnected.
If the O2 sensor is connected and closed looping, then we cannot control the fueling as any fuel changes we make will be corrected and returned to emissions compliant fueling by the O2 sensor.
 
However, your stock O2 sensor does not control the fueling throughout the entire rpm range, only at low rpms and steady cruise as this is the area the EPA wants to control because this is the range where the majority of riding is done. Once you reach a certain rpm or load on the motor during hard acceleration, the O2 sensor switches off and the bike goes into an open loop fueling. If you have the O2 sensor connected and the EJK installed, we would be able to control the fueling once the bike switches to the open loop map.
 
We only recommend leaving your O2 sensor connected if you want to be street legal (especially in California) or if fuel economy is important to you. The stock O2 sensor targets a lean AFR of about 14.7 to meet emissions; leaner usually means better fuel economy, but less performance. If you leave the O2 sensor connected, you will still have good performance in the higher RPM range or under heavy load. I apologize if I did not make that clear.
 
We recommend disconnecting the O2 sensor (whether leaving it in the exhaust or removing it completely) as it seemed to help riders with the abrupt decel (upgrading the forks will also help cope with the abrupt decel as the stock suspension was left pretty basic). If you choose to disconnect the O2 sensor, but would still like to maintain some fuel economy, then we recommend reducing the setting in the green zone until you like the fuel economy.
The Green fuel zone correlates to low rpm and light load cruising conditions.
 
So in the end, with the O2 sensor connected the EJK does not win the battle under low rpm and light load cruising conditions. We can only start to control the fueling once the bike drops into the open loop fueling.
 
Let me know if there are any other questions concerning the O2 sensor and EJK.
 
-TuningHQ

Curious, what would happen if a rider put in a switch to "remove" the O2 sensor electrically, still having it there for inspection purposes, since in some areas it is illegal to take it off.   Is splicing in a switch in the O2 sensor wiring a possibility?

[tuninghq]

Hello,

Technically, yes, someone could install a switch, but it is definitely not recommended. The risks outweigh the rewards. If they must leave the O2 Sensor connected, then leave it in the pipe, and do not add any fuel in the Green Mode.

[klx678]

Thanks, I was curious about it.

[midlifedelinquent]

On 2/14/2022 at 9:51 PM, klx678 said:

Curious, what would happen if a rider put in a switch to "remove" the O2 sensor electrically, still having it there for inspection purposes, since in some areas it is illegal to take it off.   Is splicing in a switch in the O2 sensor wiring a possibility?

I'm not saying don't break the law, but try to be informed when you do.

Technically, it is illegal to remove emission control devices, and since motorcycles in the US don't have annual inspections, it is commonly ignored.

"section 203(a)(3)(A) of the Clean Air Act prohibits any person from knowingly removing or rendering inoperative (i.e., “tampering”) any such emissions control device or element of design. EPA regulations establish the same prohibitions on tampering and defeat devices for nonroad vehicles, engines, and equipment. 40 C.F.R. §§ 1068.101(b)"

[klx678]

@midlifedelinquent like putting on a different muffler.   I'm fortunate enough to live in a place where there aren't any sort of checks required.   I will say I didn't do anything more than swap out exhausts for a nicer tone.  The stock bike was plenty of performance.  I spent the money on suspension and other things that make the bike feel/handle and look better to me.  I kind of figure if I wanted more power I should get a bigger engine.  But I'm happy the way it works on the public roadways the way it is.

Edited April 10, 2022 by klx678

[midlifedelinquent]

11 hours ago, klx678 said:

like putting on a different muffler.   I'm fortunate enough to live in a place where there aren't any sort of checks required.

Exactly my point! AFAIK, there are no US states that have safety/emissions checks on motorcycles (and I live in CA), so why go through the trouble of leaving a disconnected O2 sensor on the bike? If you're pulled over and the officer wants to give you a hard time, they would go after the fact you removed the catalytic converter.

Like I wrote earlier, it is common to ignore the law on emission tampering/removal

[klx678]

Yes, it is.  Funny part is no one would even pay attention to motorcycles in that area if it wasn't for the most noticeable pollution from too many bikes - noise pollution.    I have checked my exhaust note and it is right around 94 dB at around 5000 rpm, around 86 dB idling.  Not enough to bother anyone as I ride through town.   But then there are those who think everyone should "hear the thunder".  They get noticed and reflect on the rest of us.  

I don't know if my XSR had a cat convertor being a 2018, but it does still have the O2 sensor on it and working.   As I said I just wanted mellower sound without high volume.  Heck the exhaust might meet emissions, I don't know.