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Cat Delete...........

M

Moto-Kafe

I know some members will "blast me" for even thinking of doing this, but here goes anyway:
I ordered a used NC700X exhaust system (minus muffler) off Ebay for $45 shipped. Last night I started "dissecting" the Catalytic Converter "Pod" with a Dremel Cutting Disc and electric saw. It took some doing. I will post pics of the whole process from start to end, once I install it on the bike and see/feel/hear the results. Basically opening up one side of the Cat Pod, yanking out the Cat honeycomb "block" (which weighs 2lbs by itself), then having my neighbor weld the pod back up. Might look like "FrankenBike" on the outside of the pod, but it will be covered anyway by the plastic bellyshroud. I can see where the cat would restrict exhaust flow........tiny little holes for the gases to pass thru. There is a Cat-less header-pipe on Ebay for $235, but I wanted to go the cheap route. And if the outcome stinks, I'll put the stocker back on. The cat is held in place inside the pod by the (4) spot-welds on the outside......good size welds that require some coaxing to let go of the cat cylinder inside. I did not see any previous threads here on the forum about someone going "cat-less" (whether home-made or after-market), so if there are some, please post a link here.
NOTE: Alabama does not require vehicle inspections.

Flame away..........
Mark ("Moto-Kafe")
 
it's your bike, do what you want with it. I'm sure it pollutes less than a big cage , even without the cat. curious to see if performance improves. I have a can on mine, but it came that way.
 
Thanks Andy.........a replacement "Can" is on the list.........not for more NOISE, but less weight (and maybe some "bling"). I have an Akro Slip-On on my Vstrom650 and a Yoshi Full System on my decked-out little CB500X. I like the way the Akro sounds.....or should I say "does NOT sound". It's almost as quiet as the OEM muffler. The Yoshi sounds different, more like a Big Thumper Bike.....maybe due to the engine being a Parallel Twin vs a V-Twin (Vstrom)...??? I'm tempted to try one of the China-knock-off Akro Clones for $150 or so, instead of spending $500 for the real deal. Stay tuned........(no pun intended)
mark
 
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What is it that you are hoping to achieve in all this?

More mpg, more torque, more HP, increased seat-of-the-pants smile-factor, able to leap tall buildings in a single bound...........and chics dig it.
It's just an experiment, as I mentioned. Nothing ventured, not ever gained. Until someone shows me "hard data" (not just theories) that removing the Cat in a NC700X does NOT help engine power/mpg/etc, I will keep proceeding.
 
I'm sure it pollutes less than a big cage , even without the cat.


It is a myth that motorcycle emissions are less than cars or large SUVs...they are actually much, MUCH greater! In some cases up to 90x more emissions per mile!

Removing the cat is not only a federal crime, but also socially irresponsible.

I'm sure that the NC is on the low end of emissions since it is a new design, required to meet the newer EPA and Euro standards. But even so, it still has higher emissions (and more pollution) than a large SUV. Up to 300% more (!) per mile.
 
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It is a myth that motorcycle emissions are less than cars or large SUVs...they are actually much, MUCH greater! In some cases up to 90x more emissions per mile!

Removing the cat is not only a federal crime, but also socially irresponsible.

I'm sure that the NC is on the low end of emissions since it is a new design, required to meet the newer EPA and Euro standards. But even so, it still has higher emissions (and more pollution) than a large SUV. Up to 300% more (!) per mile.

I guess I'm not too sure. It's hard to believe, but possible for sure.
 
It is a myth that motorcycle emissions are less than cars or large SUVs...they are actually much, MUCH greater! In some cases up to 90x more emissions per mile!

Removing the cat is not only a federal crime, but also socially irresponsible.

I'm sure that the NC is on the low end of emissions since it is a new design, required to meet the newer EPA and Euro standards. But even so, it still has higher emissions (and more pollution) than a large SUV. Up to 300% more (!) per mile.
Can you explain that at all, because it seems very odd that engines using comparable materials, design and using the same fuel, so the much smaller engine creating 90X-300X the emissions of a engine that is 2X-4X the size (on the conservative side) with or without a catalytic converter sounds exaggerated.

How do catalytic converters work? - Explain that Stuff

All You Need To Know About Catalytic Converters Is They Shouldn't Exist

The second article is more biased sounding, but can anyone here point out any inaccuracies?
 
Can you explain that at all, because it seems very odd that engines using comparable materials, design and using the same fuel, so the much smaller engine creating 90X-300X the emissions of a engine that is 2X-4X the size (on the conservative side) with or without a catalytic converter sounds exaggerated.

It sound more than exaggerated...sounds impossible! ;-)

Every motorcycle engine built prior to about 2002 put out maybe 90 grams of poisons/mile. Cars and trucks were at about 4 or 5 grams/mile.

2015 and newer motorcycle engines over 270 ccs or so are rated at about 3.0/grams miles. Cars, light trucks and huge SUVS are around 1.0 or so. That would be a 300% increase in emissions while riding compared to taking a 3.5 liter twin turbo v6 and five friends ;-)

EPA doesn't require motorcycles to do better, but cars and light trucks are held to that much higher emissions standard.
 
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It sound more than exaggerated...sounds impossible! ;-)

Every motorcycle engine built prior to about 2002 put out maybe 90 grams of poisons/mile. Cars and trucks were at about 4 or 5 grams/mile.

2015 and newer motorcycle engines over 270 ccs or so are rated at about 3.0/grams miles. Cars, light trucks and huge SUVS are around 1.0 or so. That would be a 300% increase in emissions while riding compared to taking a 3.5 liter twin turbo v6 and five friends ;-)

EPA doesn't require motorcycles to do better, but cars and light trucks are held to that much higher emissions standard.
I can't find any statistics more recently then this

Table 4-43: Estimated National Average Vehicle Emissions Rates per Vehicle by Vehicle Type using Gasoline and Diesel | Bureau of Transportation Statistics

It shows motorcycles as the lowest polluter, in 1990 it was 2.75 Gram and declining.

Do you have a source for the information you've got?
 
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Myth Busters did a couple of shows on bike vs cars dealing with emissions and fuel efficiency. There were comparisons over three decades of production. The non catalyst bikes are extremely “dirty” as you might imagine. Early Emissions controls and reductions were focused on cars and light trucks and now present days all engines including lawn mowers, generators, two stroke blowers and chain saws are being looked at and regulated.

So modern FI catalyst bikes are cleaner now but no where close to modern cars. Example there are no NOX controls or misfire detection, no catalyst monitoring, Canada has no evap controls on bikes. The current NC is about 10-15 years behind the modern 2017 car as far emissions. The Large bikes like the Goldwing are about 5 years behind the cars. The Goldwing was about 5-7 years ahead of the EPA mandated motorcycle standards choosing to be much cleaner than the standards. Example .......In 2003 the Goldwing met the 2008 emissions requirements and was FI twin catalyst.

The aftershow video recaps several shows and has a discussion on methods and conclusions. You can draw your own conclusions.........freeze fame and look at the emissions. Go back and view the original shows for more details.

Bike vs. Car Aftershow 1 - MythBusters | Discovery
 
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So the question I always have for people that want to remove the cat, is why would they automatically assume the manufacturer put a catalytic converter on the machine that was too small and was restricting exhaust flow? Do they assume the intake and exhaust valves are the right size, the airbox and throttle body are adequate, but somehow the catalytic converter is undersized? In the case of the NC engine, it looks to me like the single intake/single outlet head design is your limitation to air flow.

Or, do we have some technical info on the NC700 catalytic converter being undersized?
 
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Yeah not really a high performance design.
I haven't done this but I've thought about it a couple of times.
I'm racking up miles on my NC and if my catalytic converter starts to plug up replacing it costs twice what a full exhaust system without one would.
I did try a cheap slip on and had a small flat spot as far as engine power, so I'm back to my stock exhaust.
It would be reassuring to see some dino numbers from multiple NC's with different exhaust set ups to get some conclusive numbers whether it's a gain or loss anyway.
 
Do you have a source for the information you've got?
I believe the most accurate information regarding how polluting motorcycles are would be from the EPA :

Are motorcycles a less-polluting alternative to cars
and SUVs?

No. In fact, motorcycles produce more harmful emissions per mile than a
car, or even a large SUV. The current federal motorcycle standard for
hydrocarbon emissions is about 90 times the hydrocarbon standard for
today’s passenger cars. Although many of today’s motorcycles will
actually meet the current California standards, the California hydrocarbon
standard is still 18 to 24 times the current federal passenger car
limit, depending on the displacement of the motorcycle engine.
Beginning in 2004, all passenger cars, light trucks, and SUVs will be
required to meet even more stringent standards. When these standards
become effective, new SUVs will be meeting hydrocarbon standards
about 95 percent cleaner than today’s typical motorcycle.



Link: https://nepis.epa.gov/Exe/ZyPDF.cgi/P1002K2B.PDF?Dockey=P1002K2B.PDF

Starting around 2015 motorcycle engines were required to meet even tougher standards than in the 2002 publication I quoted above, but, even these new standards are far, far below the standards for large SUVs, passenger cars, and light trucks. All of which pollute much less than a NC700 (!).

There is no question that motorcycle are the greatest polluters per mile of just about any method of human transportation except for <maybe> traveling by commercial jet airliner.
 
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Thanks for testing this OP, i'd like to see forward to a video of the gutted cat and the sound of it.

I myself am planning on getting a decat, not because of performance, but because of the "oh so loud pipes saves lifes" gimmick.

Mpg and emissions doesn't interest me as much as safety does (rev bombing the shit out of the bike has helped me countless times), and the NC is, offcource, a very, very quiet bike with the stock can and pipe.

I can already hear the rage comments :')
 
I believe the most accurate information regarding how polluting motorcycles are would be from the EPA :

Are motorcycles a less-polluting alternative to cars
and SUVs?

No. In fact, motorcycles produce more harmful emissions per mile than a
car, or even a large SUV. The current federal motorcycle standard for
hydrocarbon emissions is about 90 times the hydrocarbon standard for
today’s passenger cars. Although many of today’s motorcycles will
actually meet the current California standards, the California hydrocarbon
standard is still 18 to 24 times the current federal passenger car
limit, depending on the displacement of the motorcycle engine.
Beginning in 2004, all passenger cars, light trucks, and SUVs will be
required to meet even more stringent standards. When these standards
become effective, new SUVs will be meeting hydrocarbon standards
about 95 percent cleaner than today’s typical motorcycle.



Link: https://nepis.epa.gov/Exe/ZyPDF.cgi/P1002K2B.PDF?Dockey=P1002K2B.PDF

Starting around 2015 motorcycle engines were required to meet even tougher standards than in the 2002 publication I quoted above, but, even these new standards are far, far below the standards for large SUVs, passenger cars, and light trucks. All of which pollute much less than a NC700 (!).

There is no question that motorcycle are the greatest polluters per mile of just about any method of human transportation except for <maybe> traveling by commercial jet airliner.
WTH? The EPA statement is in direct contradiction to the United States Department of Transportation. The link I posted is a little more current (both articles are a bit out dated) but USDT had data going back to 1990 and says the opposite, so WTH? Also did you notice in the EPA article you put the link to (at that time) catalytic converters weren't mandatory on motorcycle.
I also question how bad of a polluter the NC700X is sense they haven't made a single change to it mechanically sense its release in 2012 (in the U.S. At least) and it still meets requirements to be sold?
P.S. I live in CA, we've got "special" gas and we do have the evap canister
 
It would be reassuring to see some dino numbers from multiple NC's with different exhaust set ups to get some conclusive numbers whether it's a gain or loss anyway.

There were ( are) multiple prior posts on the forum with dino numbers with charts for exhaust and attempts with tuning the FI. The trick is going back 4-6 years to find them.
 
WTH? The EPA statement is in direct contradiction to the United States Department of Transportation.

But they both agree on one thing....

Motorcycle pollute a LOT more than light trucks and cars. If you look at the table from the US DOT that you linked, you can see that motorcycles are almost 2x the pollution machines compared to light trucks and cars are.

10 grams/mile (light trucks, cars)
18 grams/mile (motorcycles)

Since 2010 (date of US DOT table) the differences are even greater, closer to 3x the pollution.

It isn't that motorcycles aren't being emission regulated, they are. But light trucks and cars are even MORE stringent when it comes to those same emissions.

I know, it doesn't make sense but the simple fact is this: That Chevy Suburban, Ford F150, and Challenger Hellcat that just passed you like you were standing still <combined> have less emissions than your motorcycle!
 
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