Topic: Project: O2 Sensor Motorcycle Exhaust Probe

[Simpson]

Couple weeks ago I purchased a used O2 Sensor/monitor and tried to fashion a attachment to my CB750/CL360 for carb adjustment. It failed horribly! Infact a small mushroom cloud came out of my garage that day. JK...

Today I got "Charlied" at a local motorcycle shop.
me - "Hey are you guys able to adjust my bike using your EGA?".
them - "Sure, give us 250.00 for turning your air screws."
me - "Can I see your EGA machine?"
them -"NO"
me - "Have a nice day"
It was obvious they care not for my business and it was flat out rude. It was that short.
He didn't even ask for details or look at me.

So today I found some pictures of a better concept to build a new one.
I'm pretty sure my O2 sensor and monitor still works (it will be tested).

-Ig/points are perfect by strobe light
-Jetting seems appropriate by intuition
-Cables and idle screws balanced by vacuum gauges

Goal: Adjust and balance air screws to same perfection
Why: Because I think this will make my bike smooth as glass

How can you expect to have a good running bike when you have diff A/F ratios in each cylinders?

This is the start of my thread to let others know of my results.
Here's what I will try to build....

[NickC]

It's going to be very hard using that setup. It will be a guessing game with the screws, because you are measuring the mixture of all 4 cyls. One can be very lean, the other very rich, but you are still getting a good a/f ratio at the muffler.

[Simpson]

I have a stock CB750 K0 exhaust 4 into 4. That picture is someone elses bike. The exchange at the end will be pluged.

[gtyler5]

whats with the vinyl tubing on the end? and what keeps it from melting?

[crazypj]

EGA is just an average unless you have bungs fitted to individual pipes.
 With that exhaust it probably isn't going to work, you need to sample from well inside pipe so you don't get outside air mixed in diluting sample, probe doesnt look long enough (you could get some stainless tube and go all the way into individual pipes from rear?)
O2 sensor is swapping volts from high to low, unless you have wideband sensor it either on or off to my understanding?
 Its about $2,500~$3,000 for a good EGA machine, any wonder they wouldn't let you borrow it?
 Got to recover cost somehow. ( I always gave outrageous quotes for bikes I didn't want to work on )
15~ 30 mins to adjust would be fair, $50~75 if they used a dyno  with EGA (its worth it)
 adjusting air screws isn't going to make it run any smoother if carb  sync is out though.

PJ

[Kframe]

On my Bonneville, I use the Innovate Motorsports LM-1 wideband controller and have the G5 gauge on my handlebars. 
This option allows for real-time monitoring the average AF reading while riding. 
(You can also go with the LM-2 which allows data logging and can hook up to a PC.)

The Bonneville has 2 into 2 pipes with a crossover pipe between the headers at a point about 20 inches from the head.  I have the Bosch 5-wire O2 sensor mounted in a bung in this crossover pipe. 

This costs about $250, which sure isn't cheap, but in the long run is much cheaper than paying a shop to do dyno's and EGA. 

Plus, it looks pretty sweet on the handlebars! 


I know a couple guys that have tried making an adapter for putting the sensor up the tailpipe, but both got really inconsistent readings.
-K

[Simpson]

Here's what I understand:
EGA samples exhaust from the tail pipe with a hose and calculates gas percentages.

See here:
http://www.etoolcart.com/gunson-gastester-portable-exhaust-gas-analyzer.aspx
http://www.automotivetools4less.com/store/index.php?main_page=product_info&products_id=3489&zenid=bbeaa64c916bfee562074aaef77f0a10

An O2 mounts on bungs on the exhaust preferably near headers to analzye O2 percentages based on Voltage pressure based on a chemical reaction.

I'm trying to adapt the O2 sensor for the end exhaust pipe.

See here:
http://www.nightrider.com/biketech/diy_exhaust_probe.htm
They remark it works well...  
 
A/F of 12:1 = (12/1) = 8.3% or 91.7% air
A/F of 15:1 = (12/1) = 6.6% or 93.4% air

This is a margin difference of 1.7% to hit the mark somewhat well.
What if you would like to make consistent 14:1 on each cylinder?

The air screws has a large impact on A/f ratio until you get past 1/3 throttle turn.
The slides open up and delute the percentage until it has near no impact.
95% of driving for me is below 1/3 throttle turn.
The idle screws adjust just that, slide position at idle for idle only.

The goal is to recreate and test this adapter from the other site and report results back here.
It's a community experiment.  

[Simpson]

I know a couple guys that have tried making an adapter for putting the sensor up the tailpipe, but both got really inconsistent readings.
-K

That's what I'm afriad of...But I'll give it a shot! 

[Hinz]

To give you some background, I used to build turbo AWD Eclipses and Talons professionally and I'm pretty familiar with these gauges.  I've used them in tuning race cars before and they're better known as "Widebands" rather than "EGAs".  I'm just saying so when you Google search you come up with more info....

Anyways....
Since our bikes have 4 independent cylinders, a wideband at the collector or the muffler isn't going to work right for tuning the carbs. You would effectively need 4 widebands, one for each down pipe...that's pretty pricey at $250 each.

When we used these widebands on racecars in the past, they worked ok in the tailpipe because the cylinder's intake is "balanced" by having only one throttle body or carb that feeds air & fuel to all the cylinders equally.  Meaning, if you adjust that single carb (or the ecu), the entire motor follows along with the changes you made...each cylinder will receive the same amount of fuel & air. 
Now, our bikes have individually adjustable carbs for each separate cylinder. Who's to say that one carb isn't falling behind while the other 3 are taking up the slack...everything seems kosher but meanwhile you're burning up that 1 lazy cylinder.  For your method to work, you would need to do a single carb conversion and I haven't seen them available for our bikes in years.
IMHO a better/cheaper way (however be it more "caveman") would be to get 4 EGT (Exhaust Gas Temperature) probes and install one probe in each down pipe coming out of the motor.
The temperature of the exhaust gas will give you a decent estimate of how rich/lean each cylinder is running...
hot cylinders=leaner
cooler cylinders=richer
however, there can be some variables....
Such as a really rich carb with bad ignition timing can make really hot EGTs since it's literally burning fuel IN the exhaust pipe.

All in all, I think all of this is a little over the top unless you're doing some serious mods to the motor or adding forced induction to your bike. If it's all basically stock....just bump up a jet size, balance the carbs with a manometer and call it a day.

[Simpson]

Anyways....
Since our bikes have 4 independent cylinders, a wideband at the collector or the muffler isn't going to work right for tuning the carbs. You would effectively need 4 widebands, one for each down pipe...that's pretty pricey at $250 each.

Hiinz,
You have some good experience here!
Question:
Why will the sensor not work in the muffler?
Is it because it is allowed to cool down?
Do you think the link showing the sensor mounted on the back is a fake (bullcrap)?

[Hinz]

Anyways....
Since our bikes have 4 independent cylinders, a wideband at the collector or the muffler isn't going to work right for tuning the carbs. You would effectively need 4 widebands, one for each down pipe...that's pretty pricey at $250 each.

Hiinz,
You have some good experience here!
Question:
Why will the sensor not work in the muffler?
Is it because it is allowed to cool down?
Do you think the link showing the sensor mounted on the back is a fake (bullcrap)?

Maybe I should rephrase my statement...The sensor will work and the gauge will light up with a reading, but on a 4 cylinder/4 carb bike, that reading won't be an accurate representation of what's actually going on in the motor.  As for the pics, I don't know what bike that is in the pic, but if it's a thumper (single cylinder bike like an SR500) it would work just fine since there's only 1 carb/1 cylinder/1 exhaust pipe.
As for the placement of the O2 sensor, companies like Innovate sell a Wideband sensor mount for testing cars on a dyno.  The mount samples the exhaust gas about a foot into the end of the tail pipe.  
Check it out.
http://www.innovatemotorsports.com/xcart/product.php?productid=16141&cat=271&page=1
This effectively puts the sensor, oh about 8-10 FEET from the cylinder head.  So, even where this guy has his sensor mounted, it's not nearly that far from the head as compared to a car.   As long as that sensor isn't just sitting in open air, it should work ok and it seems he built something similar to the Innovate unit to sample the exhaust gas.
 

[Hinz]

I did a little investigating and those pics are from a Harley site...
...shame on you...
j/k.

Anyways, that Wideband setup would work on a Harley since their motors have 2 cylinders fed by a single carb.  This is one time where the Hardleys have an advantage over us. 

[j squared]

This sounds pretty interesting, Id like to see how the tail pipe sensor works with your 4-4 exhaust.  All things considered it should work fine IMO and give you good enough readings to see any variance. 

I have considered welding O2 bungs into each of my 4 primary runners for wideband readings on the shop dyno, but thats way past the point Im at with my bike now   Maybe once I get it out of the garage...

[Inigo Montoya]

I would think that if a person still has the 4 -4 setup that this would work, provided you could keep the sensor hot enough. A typical narrow band needs to be about 600 degrees F to read right so getting in the tailpipe far enough might be tricky. Otherwise, With 4 carbs, I feel it should be fairly accurate. not perfect of course but you should be able to get a fair reading on each cylinder. Lets not confuse sync with a/f mixes here. That should be done first anyways.

[Simpson]

I'd like to continue but I've got to a point where I'm not comforable spending anymore money on it. The sensor I'm using is very suspect and a new setup will be couple hundred dollars.J ust bought two brake reservoirs for my Speed Triple so the budget is spent this month already.