Yeah that was one of the reasons I didn’t stick with the x-pipe. It definitely stank!

:-(

 

You've removed the bit that filters out most of the noxious fumes.
Carbon monoxide can kill you, so I wouldn't advise leaving it idling in an enclosed space.

 

It don't stink when riding, but running any motor in a garage will stink and no need to idle it for 10 minutes as the ECU will addap on the first ride.

Ashley

 

Funnily enough, my T100 stank when running it in the garage on first start up. That was following the winter lay up and the fuel was laced with stabiliser. It was so bad I considered putting the cat back on. But wait! After a decent ride the smell went away never to return. I have no idea ‘what or why’ but it’s a fact. Go ride your bike! ?

 

That's what I'm hoping Simon. I'm just going to wait to see if a clean tank of fuel will help. It's so bad just standing behind the bike stank up my clothes pretty bad. Not the end of the world - just different.

 

If in the current state of things you are all riding your bike in the garage I strongly recommend not starting the engine , just sit there and go brrrum brrrum . ? ???

 

My previous non cat equipped bikes did stink when run in a confined environment. Its not just CO the cat removes, it also converts hydrocarbons to water and CO2, most likely the gas stabiliser also contributed to the stink.

 

Actually, the cat converts hydrocarbons to NoX. A catalytic converter is only there to burn off any fuel not burned in the cylinders but CO2 will always be produced by burning hydrocarbons whether in the engine or further downstream.

 

Nitrogen oxide and nitrogen dioxide, which stink, are converted to nitrogen and oxygen.

 

So I guess people live with it for the performance gains and sound? I can’t imagine putting the cat back on at this point! [emoji3]


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Wouldn't the change in restriction affect the jetting?

 

There’s no jetting on computerized EFI bikes. Jsobell from OZ tested the effects of exhaust mods on power and air/fuel on a dyno. The bike was a Thruxton. Replacing the cat with a Meerkat crossover had little effect on the air/fuel and added some power. Adding slipons didn’t affect the air/fuel or power. The Meerkat sounded great on my T120.

 

When idling a vehicle in the garage its always good practice to have the garage door open or have an exhaust vent. When I did mine, I created an exhaust leak at the header gaskets. I smelt exhaust fumes intermittently while riding or while at a stop. Took me a little while to figure it out.

 

Oh for sure. I always have the garage door open if the bikes running. I could smell the exhaust when walking behind the bike. More so than it used to.

Last thing I need is running a vehicle in the garage with the doors closed. That’s one nap I don’t want to take any time soon.


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Aside from black streaks, you can use cigarette smoke to diagnose leaks.

 

Obviously been awhile since I was in chemistry as well. As a trainer for Sun engine analyzers it was oxides of nitrogen that were being produced by the cats.

 

look it up

 

Thanks @Dougl1000! Very easy to understand and I learned something.

 

Yes absolutely - removing your cat caused the exhaust gases to smell more. Combustion byproducts include nitrogen oxides - which include nitrogen dioxide which has a harsh unpleasant acrid smell. Your cat causes the nitrogen oxides to disassociate in nitrogen and oxygen which are odourless. It also converts Carbon Monoxide into carbon dioxide. CO is very dangerous.

Did the stabilizer make it smell even worse? Possibly - I don’t know what other byproducts are introduced by stabilizer that a cat would treat. But - regardless - removing the cat made the exhaust smell more and made it much more dangerous in a closed environment.


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Rip, as I said earlier, my experience was exactly the same on first start up. The problem went away somewhere during the first ride. How? Why? Damned if I know. I just know it did. The stink was so severe on first start up that I even considered putting the cat back on. Glad I didn’t.

 

Even if I still had a catalytic converter in any of my three bikes (I don’t), I wouldn’t be running ANY motorcycle in a garage for 10 minutes!

 

What about some modern cars with catalytic converters when behind them and they smell like rotten eggs.

 

Had the same experience immediately after decatting, a strong fuel smell after start up. Thought it was the result of decatting. Turned out one of the fuel manifold seals had gone bad. My dealer replaced them under warranty, and there's been no fuel smell since.

 

I've d-cat'd several bike of different brands, including my '19 Street Twin and have NEVER noticed any unusual odor. Of course I'm an old guy and my sense of smell ain't what it once was. Oh how I miss the fragrance of those sweet young maidens.

Paul

 

How long unto someone suggests that catalytic converters are a conspiracy ?! We are humans not mass spectrometers. Even if we cannot “smell” it, perhaps some consideration of the broader well being or pollution we cannot smell might be a consideration?

In any event, I swear removing the snorkel also has a detectable albeit minor improvement in feel... ( Asa conical Stone note I definitely cannot smell that change.) Curiously, I never see any threads about that. Anyone else done it and think it changes anything? It seems equally likely that my mind is playing tricks on me.

Happy parts removals!