Really just a thought, but I was wondering if you could use the oxygen sensor from a fuel injected bike, to rig up a rear-time meter that would tell you if the mix was right?

I assume that these sensors are used to tell the fuel injection management system, how rich or lean the burn is.

So could you theoretically plumb one in around the header exhaust pipe area, and wire it to a display somewhere, that would tell you second by second, if the mix is right?

It could tell you if the bike's running rich at high revs, or needs to be leaned out all through the range, or at what altitude the bike's running best etc.

It would just be interesting to know accurately, what the bike's doing. Not necessarily for an overland adventure, but maybe to get the bike setup right before you leave, or to know how you need to jet when you climb mountains.

What do you think?

Hey Baron Bolt…on.

What a good idea, great for the perfectionist and great to make sure that your carburetor system is always in tune or be able to see what it is doing. Think its a great idea.

Me I think if I had any concerns with a carby bike I would rip in for a Dyno tune before I left for RTW and once the jets are chosen they are set then there is no need to be anything else but standard and usually unless your bike is used for racing.

Eg changing cams, exhausts, bore size, rod stroke ratio, increasing flow to carby’s. porting and polishing etc etc and generally putting your engine on the edge.

However just a thought changing jets in the carb may not be a lot of fun on a minute to minute basisin the cold and usually high altitude. where everything always seems twice as difficult and heavy.

As the valleys meet the mountains it’s up and down continually changing.

Unlike small aircraft which has a mixture adjustment that is controlled from the cockpit and is usually adjusted on start up and taking into consideration small aircraft usually fly at a nominated height and rarely vary that height from point A to point B

So considering the fitment of a sensor, consider also an adjustable main jet which was made a long time ago for the FJ Holden (1950s Aussie car) as part of a tune up kit Yeo….. brings back memories

Carbs have come a long way and the alternative was to design a fuel injection system so (an old mate of mine (Ivan Tighe… Tighe Engineering and Cam Grinding) designed the Amil carburetor back when Jack Brabin was winning Formula 1 (it was developed through REPCO along with the REPCO Brabham race engine: interesting and knowledgeable Fellow) everything could be perfect….. perhaps the other alternative would be to design an aftermarket fuel injection kit , they have them for cars and I looked into an aftermarket kit for bikes but couldn’t find one: it would be good if the electronics were perfectly sealed from dust and water.

Sub Note:- FJ Holdens Late 40S-50S Jack B about 60S was a spectator when Jack blew the REPCO….Red Hot bits were flying all over the place up the back strait of Sandown Melbourne…. tossed in 20 quid to assist with a rebuild (don’t have a pounds sign on my key board)

Go for it

Kind regards

Champ

Yes, this can be done. There are 2 types of o2 (aka lambda) probes, narrowband and wideband. As the name would suggest the narrowband will tell you if you are chemically correct or not whereas the wideband will tell you how far out you are. Wideband typically used for diesels, depends what you are aiming for. You'd need to get a boss welded into the pipes to fit it (can be found on ebay under 'lambda boss').

Some have more wires than others for a heater but basically they output a voltage to indicate mixture.

This voltage has very little current behind it so if you measure it with something that pulls even a small current (moving needle meter) it will pull the voltage down and ruin the measurement. You ideally need to pass it though a high impedance op-amp and then read the voltage somehow after this (multimeter or something).

If this all sounds doubledutch there are pages scattered on the net for how to do all this. You can also buy the complete thing again on ebay although they can be around £150.

N

__________________
Belfast to Kathmandu on a Diesel motorbike 2010/11 www.suckindiesel.com

There a lot of products for lambda-tuning, here is one:
Wideband Lambda Gauge | Stack | Demon Tweeks Motorsport, Motorcycle, Car Modifying, Parts and Accessories,Sparco, Arai

Or you could make your own:
D.I.Y. air/fuel ratio meter

Well that all sounds pretty positive. As I said it's really nothing more than a thought at the moment. But it sounds like it would be an interesting (educational more than anything else) project when I get home.

That demon tweeks thing looks suitably sexy, but not sure about the 230 quid price tag. I was thinking more along the lines of trying to get an old Lambda sensor from a FI bike at a scrap yard, and wiring in the leds as an indicator.

But what about this wideband narrowband difference?

The demon kit says it includes a wideband sensor, as does the DIY kit. What do they use in bike FI systems?

(Just had a read through some wikipedia articles, and it says:

"The original narrow band oxygen sensors became factory installed standard in the late 70's and early 80's. In recent years, a newer and much more accurate 'wide band' sensor, though more expensive, has become available.")

I was thinking of making up a short section of tube that would be clamped in between the existing header and silencer. This section would have the hole drilled and boss welded. This way it'd be removable, and hopefully easier to bolt on to a different bike. Plus no mods needed to the exhaust components that are on the bike at the moment.

Ebay.com has some stuff. I searched wide* lambda* and found 150 buck sensors, or kits for 200. hmmm