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Hi all.
I have done a search of our archives and have found a few interesting posts on catalytic converters. My 312 has it's catalytic converter welded to the headers. From a previous post I think that's an indication that it's a "euro 3" spec bike. I can source the headers, no problem, but here is the issue you may be able to help me with.
There is a sensor that bolts into the link pipe just beyond the catalytic converter. I've attached some pictures.

I unplugged the sensor from the wiring loom and turned the ignition on. No worries. I then start the bike, warmed it up and it runs fine.
What is the sensor called and what is it sensing?
The reason I ask is that I'm going to remove the catalytic converter and replace it with a titanium link pipe. The titanium link pipe does not have provision for the sensor unless I have it altered. It's a round hole trying to get into a square peg.
Thanks,
Dave.
 

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Dave,

That's an O2 sensor which feeds the ECU info to regulate the A/F ratio. I don't know if it's required in your upgraded situation but if so the "bung" is threaded with an 18 mm hole and is a standard fitting readily available to be welded onto your Ti link pipe. Small potatoes this one.
 

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As Lee says it's a Lambda or O2 sensor, with the standard ECU it is needed (or at least a connector that offers a duplicate signal).

With the 'Race ECU' I believe it becomes redundant and may be able to be eliminated, however this is not a bad sensor to leave in (depending on the ECU programming), so if you can I'd suggest the replacement exhaust system also includes a Lambda probe hole.

Most bikes only utilise the Lambda probe below about 5000 rpm and at constant partial throttle settings (i.e. when cruising). At full throttle and when revving hard the systems will revert to a pure mapped ECU setting. I don't know exactly when the Lambda prope operates on the MV though.

Andrew...
 

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Of course, you know you can't just weld the steel bung to the titanium midpipe like you would to a steel midpipe.
 

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Sorry Caggie but oh yes you can. I have a guy who does my critical welding and he does it all the time with his Tig. He also works for Usair in the engine shop and does repair to Ti engine components.
 

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Uh, no you can't. When he is welding titanium, he uses more than just the argon from the torch.

Either he:

1) puts the piece in a sealed container so the complete atmosphere is argon, or
2) he has some sort of device rigged up that injects argon gas to the back of the area he is welding.

Feel free to correct me again if I'm wrong.

Do I sound smug? My wife says I sound smug. I don't mean to sound smug.
 

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You can't just plug in a resistor to trick the ECU with flat lambda signal either (that's why the DynoJet o2 eliminator won't work on Euro 3 Ducati and MV among others, so you can't use the PCIII).

The ECU looks for a varying signal (which is what it sees with proper working o2 sensor) and triggers a fault/fail safe mode if it doesn't see that. There are o2 sensor simulators available from the hot-rod tuners that send a sine wave signal to the ECU. I bought one to test, but got a race ECU before I got around to it. About $50.
 

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Feel free to correct me again if I'm wrong.

Do I sound smug? My wife says I sound smug. I don't mean to sound smug.
My wife and daughter do that all the time....

And yes, Caggimundo, you do sound smug. I'd be hesitant to challenge the old troll. He seems to know what he's talking about when it comes to arcane stuff like this......

after all, how does one challenge a guy that plays the bag pipes?
 

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I got ya bag pipe right here!

I think I'm right on this one. I have inside knowledge. (Remember, I learn from experience)
 

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You got zip my dear. The Tig blows Argon and the interior of the pipe is purged with a steady flow of Argon. Beautiful inside and out.

Don't mess with the naked Phantom.
 

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AH HAH! I was correct. Unlike ordinary steel welding where just the argon from the tip of the torch is enough to create a clean atmosphere, welding titanium requires argon on BOTH sides. Thus, your nuclear aircraft space age welder uses step #2 to weld titanium. Which means, and I qoute, "you can't just weld the steel bung to the titanium midpipe like you would to a steel midpipe."

CAG shoots, he scores!

It's CAG from Down town!
 

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Discussion Starter #15
I work with a guy called Bruce Barclay who used to be a mechanic for the 500cc Motogp Yamaha ridden by Gary McCoy. Among other things he would repair the titanium headers when the were fractured due to fatigue. I am not a welder but I do understand what's being said in the posts above......just. I'm going to ask Bruce for his opinion of the best method of making this round peg fit a square hole. I'll let you know what he thinks about this.
 

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Don't mess with the naked Phantom.
Lee...is this an admission that it is, in fact, you on the Tambo in your birthday suit as pictured elsewhere??? :jsm: :stickpoke:stir:
 

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Let's stop all the dick wigglin.....why not just buy a steel mid pipe? It can't weigh more than a few ounces more than titanium, right?
 

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Discussion Starter #19
Randy, alas the 312R mid pipe is welded to the headers. Can't just replace it with steel mid pipe.
I'm gonna keep wigglin' 'til I get some satisfaction.
 

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The main advantage of the titanium midpipe is not its weight savings over steel, it is that it looks sexy as hell.
 
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