Hello there! Its been a while since ive been on here.. but its been even longer since ive riden the bike. I started it up today and it ran pretty good. Died a few times while warming up, and smelled pig rich. So i decided to try out my wideband o2 sensor to see the afr. The problem is the AFR at the tail pipe on the left side was reading 26 AFR and on the right 32 AFR. This obviously cant be, probably just wideband placement in the exhaust pipe. What I am wondering is if anybody on here has tried tuning with a wideband as well and if you noticed the same results by placing the widband in the tailpipe.

I know tuning cars by placing in the tailpipe will yield approx results. But 26 and 32 sure as hell cant be Approx.

Thanks!

 

Well, unless fully warmed up and at part throttle, the two pipes will flow a lot differently, so with a few variations on placement thrown in I'm not to surprised at the difference... The good way to place it is with bung on the header pipe...

 

they make a mount for the wideband that inserts it far down the tail pipe. otherwise you'll get contamination from outside air/turbulence at the exhaust end (my understanding). the best is to mount a screw type bung adapter of course, but I believe the mounts work OK also. You could search in here for the end pipe mount

http://www.innovatemotorsports.com/products/lm2.php

exact link to exhaust mount:

http://www.innovatemotorsports.com/x...cat=271&page=1

 

Also until you either remove or disable the PAIR system you exhaust gas readings are useless.

 

Exactly, you need to disconnect and plug the vacuum line that goes to the pair valve under the airbox, right by the idle adjust, if it leaks, it will mess up the results, you can try to take off both hoses and plug them.
I guess that you have already done the free air calibration, right ??

 

I'm using a narrow band O2 sensor on my bike. I placed the sensor in the short piece where the two headpipes merge together. It takes a short bit to heat up before you get good readings, but overall it works well. I'd love to switch to a wideband but the hardware is too expensive to justify, even now that the prices have come down. I think I have less than $100 in my setup total.

 

I have posted this before.
http://14point7.com/Widebands/NAW_7S/NAW_7S.htm

 

Would anyone mind enlightening those of us who don't know what this application of the terms "wideband" and "narrowband" mean, or what "AFR" means, and what the purpose of all of this is?

 

AFR Air Fuel ratio you are trying to reach stoich which for gasoline engines is around 14.7 to 1
Wideband and narrow band will tell you where you are in relation to this perfect mix.

 

Wideband and narrowband refer to what? These are adjectives, what is the noun? Where I come from they are types of radios.

 

google is your friend
http://www.clubwrx.net/forums/cockpi...afr-gauge.html

 

EFI systems on cars use narrowband O2 sensors to monitor the presence of unburned O2 in the exhaust gas, during closed-loop operation. If O2 is present, it richens the mixture, if it is not, it leans the mixture. If it were to always run lean - with excess O2, the mileage would go up, but the catalytic converter would overheat. So the O2 sensor allows the EFI system to toggle back and forth between rich and lean mixtures.

During open-loop operation (e.g. wide-open throttle), feedback from the O2 sensor is ignored and the fuel map is used without alteration.

Maximum power comes from a slightly rich mixture (excess fuel), because it ensures that all available O2 is consumed. So to use a narrow band O2 sensor, you would find the point where the sensor swithces to lean, then fatten it up a bit. But it is a two-state device.

A wideband O2 sensor, outputs a varying voltage as the amount of O2 changes.

 

A clever setup would be two bungs for the two cylinders with two plugs when done, so you can tune both carbs independently.
Narrow band 13.5 to 15:5
Wideband 7 to 22 AFR

 

Thanks for the info. Based on the picture of the mount, how do you believe the wideband would sit in the exhaust stream? Kinda looks like it would just put it directly into the exhaust pipe correct?

Great info guys! I figured the readings that i was getting had something to do with the exhaust flow.
I have disable the Pair completely as well as the reed valves. Ill start her back up today and see what kind of readings I can get, but probably not going to be very accurate untill I can get a bung welded in her.

And i have free air calibrated her. Ill let you know what I find..

 

mmmmm... Thats a good idea!

 

I looked at my friends dyno and the way that they calculate AFR is a long copper tube down one exhaust to a venturi vacuum that has a O2 sensor attatched to it.