O2 Sensor Location?

[Paul Smith]

Is there a position on the exhaust that suits both wide and narrow band sensors? I'd like to be able to run around with a NB hooked up and then use the same bung for the WB.

[joshdiy]

As long as the bung is located between the cat and the engine you should be able to use the same location for both wide and narrow. The only thing to consider is the heat range of the sensor you are using. For example:

"The Bosch LSU4.2 wide-band O2 sensor (shipped as part of the LM-1 kit) is rated to operate at an exhaust gas temperature of < 1300 degrees (F), and a sensor housing temperature of < 900 degrees (measured at the bung) for maximum accuracy and control."

[Paul Smith]

Crikey. I don't know how I'm going to measure that. Can anyone hazard a guess at a distance from the dump pipe of the turbo? All of the NB sensors I've seen are mounted in the dump pipe. Would moving it further away down to the ideal spot for the WB be a problem?

[rs2000]

If the NB is a heated type, you can put it anywhere you like. If the NB is not heated then you need it to be at the correct temperature to work, so the position is very important.

IMHO its a bad idea to put any oxygen sensor after a join in the exhaust pipe as any leaks will mess with the readings.. I have mine in the base of the extractors

[Paul Smith]

Thanks for the help guys. My NB is the heated type so it should be ok. I will have to have them after a join though as the dump pump only has a 4" drop on it. I'll make sure the seal is good.

[triangles95]

I'm converting a Kawasaki Vulcan 500 (500cc parallel twin). The two locations I can put the O2 sensor is about 3 inches from where it comes out of the head, or underneath the motorcycle just behind the engine. My first choice would be 3 inches from the head, but I'm worried that the temps may be too high. Is it possible for the exhaust to be too hot? I believe flame exits the combustion chamber and goes 3-6 inches down the exhaust under normal operation.

[EWflyer]

I looked at a few pictures of the Vulcan 500 and I saw it's configured with a seperate exhaust for each of it's two cylinders. This presents a situation that goes beyond the "where to put the O2 sensor" question you asked. If you keep the bike's current exhaust system you'll only be able to put the O2 sensor on the exhaust gases from one cylinder, so your question is "where to put the O2 sensor, and which cylinder do I want the O2 sensor to analyze?"

I'm also working on a small (Kawasaki EX-250) parallel twin motorcycle engine. My bike's exhaust was configured just like your Vulcan's with one full exhaust per cylinder, and no mixing of gases between cylinders (yes, the exhaust had a "crossover" pipe connection between the two exhausts but this doesn't really mix the cylinder's exhaust gases to any real degree). I got rid of the "1-to-1" exhausts and installed a "2-into-1" exhaust. Then I welded the O2 sensor bung a couple of inches after the merge-point of the exhaust system, which put it just behind the engine (in the little space between the rear of the engine's oil pan and the bike's main suspension mounting point).

I'm sure there are others who have engines that present them with this "separated-exhaust system" problem. There are probably strategies for dealing with it, a compromise that you can make in deciding where to put the O2 sensor.

[triangles95]

I had intended to run an 02 on each cylinder, but it looks like you'd need megasquirt to do this as I only see one 02 input on microsquirt? As far as I know there are no aftermarket exhaust options for my cycle let alone one that was 2 into 1. where did you get yours? our engines are similar enuff that I may be able to shoe horn something on. I am exploring having an exhaust shop fab something up, but that may be too expensive.

[EWflyer]

where did you get yours? our engines are similar enuff that I may be able to shoe horn something on.

If you're interested in the possibility of making an aftermarket 2-into-1 exhaust fit your Vulcan I'd say you've got at least a chance of making it happen. Yes, your 500cc Kawasaki engine and my 250cc Kawasaki engine have very similar external dimensions, so it wouldn't be a big stretch to make an aftermarket exhaust from my bike fit onto yours. The big question with your Vulcan is: How much room do you have behind that big piece of frame that runs down in front of the engine? The EX-250 doesn't have that restriction. From the Vulcan pictures I've viewed on the web I'd say there's a substantial amount of room there between the engine and the frame piece but I can't quite tell if there's enough for an easy-swap installation of an aftermarket EX-250 exhaust. It might require having a "Vulcan 500 application specific" set of header tubes bent to get to the merge collector.

All you would have to do is determine if the geometry of an EX-250 aftermarket 2-into-1 exhaust will work with (or at least be close to) the geometry needed for your Vulcan. There's a bit of "wiggle" room in an aftermarket 2-into-1 system. They come in four separate parts: the headers (2), the mid-pipe merge collector, and the exhaust itself. When you're putting it all together you have a few degrees of rotation available at the connections. When you've got it all aligned like you want it, you put on the springs that hold it all together.

It could work for you "right out of the box" or it might require a little bit of geometric "tweaking" by someone who knows how to bend stainless steel piping. Once again, if it wasn't for the difference in the two bikes frames I'd say the EX-250 and your Vulcan are a pretty close match. You'd also have to find out what the exhaust port diameter is on the Vulcan 500 so you could compare/match that to the header-seat diameter of any exhaust you might be considering. I'm betting the attachment method and bolt pattern/spacing is "Kawasaki standard".

My bike's exhaust comes from Area-P in Anaheim, CA. Kerry Bryant, the guy who runs Area-P is a very nice person. I'm sure he would be willing to email or even talk on the phone with you about the possibility of making this work. You could get the measurements and angles (and any other pertinant numbers like header-seat diameter and bolt pattern/spacing) from him so you could mock up or otherwise simulate it's fit to your bike.

[triangles95]

WOW call me cheap but even if it would work $450 would blow my budget. My exhaust ports appear to be significantly farther apart than yours. in Kawasaki's engineering departments infinite wisdom they put the frame members almost directly in front of each exhaust port. I have both a 94 and a 06 vulcan 500. The 94 has even less space. The 94 is the guenna pig. If I get it working to my liking, I'll replicate things on the 06. I'll have to see if there is a way to use 2 O2 sensors with the mircrosquirt. Otherwise I suppose I can put a bung in each side and use one side at a time. switching sides to make sure both pistons are running ok.