Fin
That sounds reasonable as it would be more money but guarenteed to work and I dont have to invest time in building it which is major premium for me right now. I definatly would like to see your exh sniffer. I was thinking of makeing a pipe that I could stuff upt he exhast that may restrict it a little but still would be 5 or more times the stock exit hole.
Cheers, Jim

 

Measuring gas from the tailpipe on a single cylinder bike is a bit problematic.

A surprising amount of air is sucked into the end of the exhaust pipe during the negative surges. The way most bike exhausts are designed, it is not possible to insert the probe far enough into the pipe to get to the "clean" exhaust. The result is a dilution of the gas sample. In other words, the readings are mixed with air and appear much leaner than they really are.

BTW, I have been designing and manufacturing emission analyzers since the mid 90's. Here is a previous model:



Ron

 

That's very cool Ron! Just for my education, what kind of price are we talking about for five gas analyzer?

The dilution of exhaust gases with "backwash" of air is very true. Welded bung further upstream is the preferred method but not always practical. I'm using a venturi tube provided by Innovate that's specifically designed to take as clean sample as possible of the exhaust gases flowing out.
Singe cylinder engines are worst, the exhaust pulses are very strong and timed far apart. That really wants suck in air between the positive pressure waves.
For that reason with the KLX (FMF pipe on it) I had to go step further and put the venturi pipe inside an another pipe that sticks further into the muffler.
Most of the exhaust (and the backflow, I imagine) flows on the outside of my sniffer pipe and that seems to work.

Ron, how much exhaust gas analysis you've done with KLX? Any interesting findings you'd care to share?


And by the way, are you still using the stock snorkel on your bike?

--
Mikko

 

Ron
Good, easy to understand exhaust gas information on the web site:
http://planet-equipment.com/
Click on Exhaust Analysis.

But, no purchasing information.

Ride on
Brewster

 

Ron
Since you have been building them can I ask how the gasses are being analized & with your 5 gass analyzer do sensors need periodic replacement?
From my limited experiance in gas analisis here is how I understand the gasses I have been analyzing are actualy sensed

Oxygen- Fuel cell that generates voltage proportinate to the pressure of oxygen(Pressure can be converted to percentage at atmospheric but the cell actually reads pressure), Periodicly need new senseor cell.
Helium- Mesure of heat transfer charchteristics Not relevent to Exhaust. Does not go bad over time
C02- The system I worked on was for a diveing chamber and it ran gass thru a glass tube and some kind of IR or UV light thru the tube. CO2 changed the amount of light the light was pulsed by a wheal with a section cut out of it called a chopper. The chopper was not spinning and thats what I fixed. Do not go bad over time
CO- I dont kow what method is used but the sensors I have used are 4 wire so I assume there is an input and a readout but they do go bad over time so ther must be a chemical reaction that gets used up.

Cheers Jim

 

That analyzer is now discontinued because of component availability issues. It sold for $4000.00.

Backwash: I've got piece of silicone tubing about three feet long. I attach that to the back of the muffler tip and then insert the smaller probe through the center of that into the muffler. I'd like to see a picture of your setup.

My KLX has about 2% CO and 100ppm HC at idle. I haven't tested it under load.

It's kind of strange, I guess, since I've got a number of emission analyzers, but I do most of my jetting by driveability and feel for the low and mid range and top speed runs for the main jet.

And yes, still using the stock snorkel. It works better for me than the other options.

Ron

 

I'm familiar with that, Brewster. I wrote it.

As I mentioned to Mikko, that analyzer has been discontinued.

Ron

 

You are pretty close on most of it, Jim.

Electro-chemical cells are used for O2 and NOX, not pressure. A voltage is produced depending on how much O2 or NOX is available.

HC, CO, and CO2 are just as you said. An infrared light is aimed down a tube (sample chamber) with an infrared detector at the other end. When gas is introduced into the chamber, some of the i/r light is absorbed. That gets processed and displayed.

The chopper wheel is there to so that the circuitry can be switched between a zero reference of some kind and the chamber(s) with gas. Modern infrared analyzers no longer use chopper wheels. Now it's done electronically with multiplexers.

The electro-chemical O2 and NOX sensors start deteriorating right away. They usually have a service life of a couple of years.

The i/r detectors and light sources aren't really considered consumable items, although they do eventually wear out. They can last 10 to 20 years or more.

Ron

 

On this one I think I am correct in they read pressure of oxygen. more accuratly they read partial pressure of oxygen. Which at atmoshperic pressure is also %Oxygen

We use them in "Nitrox Analyzers" to determine the oxygen percentage in a divers supply tank. There the display is calibrated so the readout is .21 for air(21% Oxygen .79%Nitrogen aproximatly) & 1.00 for 100% oxygen. But we also use them for reading the partial pressure of oxygen in closed loop rebreathers. In that case the % ratio of oxygen in the mixture may stay the same but the pressure increases as you go deeper. For example at 100' the pressure is 4 times what it was at the surface so the cell will output 4 times the voltage which will cause the display to read .84 even if the % is still 21%. When tuneing a vehicle of course you really are concerned with what is happening at standard atmospheric pressure so I guess commen terminoligy is in %. I show my students that pressure affects the reading of the analyzers we use by blocking the exh flow a little and allwing the pressure on the cell membrane to increase a little(too much will damage the cell) this causes the reading to increase slightly. The reson for this demonstration is to demonstrate why it is more accurate to use a regulator and an oriface to give consistant flow rates and pressure on the cell for given tank pressures. The other option commenly used is an oriface held up to a scuba tank valve which will flow more or less depending on how much pressure is in the tank or how tightly you hold the oriface to the valve.
Sorry got on a ramble but just thought I would throw out some FYI where I actually have some experiance.

I think I may look for the analyzer flying fin has.


Do you guys think you could simulate load by sitting on the bike with front tire against a wall and slipping the clutch in gear? I think if you just did it a bit you should not ruin the clutch and it would give you an idea of work under load.

 

Pictures of the A/F meter I'm using.

Generic view of the setup on the KLX. It's all temporary wiring just there to get the jetting done.


The meter itself is temporarily mounted on what's normally the Ram mount for GPS.


This is one of the screen modes when meter is on. It's also possible to record RPM's and TPS reading. Here the engine is not running and meter reads A/F = 20.9


This is the venturi tube and the additional "sleeve tube" I'm using to sample the exhaust gasses. I've so far used welded on bungs on header or input side of the muffler, for the KLX I wanted to make it bit more portable and easier.
The venturi tube is the key for taking a sample from the end of the pipe without letting the backflow of air to dilute the gasses. It basically lets only gasses that flow, to the left in this picture, to get to the wide-band lambda sensor.


This is how it looks bungeed to the exhaust tip


Probably not perfect bu gets the work done.

--
Mikko