Question Which de-cat pipe

[Wedders]

I am considering a change in exhaust pipe to remove the ugly and restrictive cat. On eBay I can only see 2 a black widow and another one I can’t remember at the moment.
Has anyone gone through the same? and give me information on what you used and what you think is best.
Thanks

 

[670cc]

I am considering a change in exhaust pipe to remove the ugly and restrictive cat. On eBay I can only see 2 a black widow and another one I can’t remember at the moment.
Has anyone gone through the same? and give me information on what you used and what you think is best.
Thanks

Do we have data that indicates that the catalytic converter is too small? I don’t see why Honda would design the motorcycle with an undersized or restrictive catalytic converter. They did well designing the airbox, engine, throttle body, etc.

 

[Wedders]

Any restriction is too much. In the U.K. exhaust emissions are not tested so there is no need legally for a cat so why not get rid of it.
BTW I’ve just bought a Leo Vince full system off eBay for a good price.

 

[superchargedv6]

The days of super restrictive cats is pretty much over and ended in the 80s. I highly doubt you'd see much of any difference at all even on a dyno between an catted and uncatted bike. Leo Vince does/did sell an uncatted header pipe to eliminate it if you feel that strongly about it.

 

[Wedders]

I don’t feel that strongly about anything, I’m just a persistent messer around. At the moment my bike is complete so I’m looking for something to change. I have a Fuel can on at the moment which came with the bike and it’s ok but in my mind not a premium set up like the Leo Vince. Call me as much as you like it’s my hobby being stupid.

 

[mzflorida]

I don’t feel that strongly about anything, I’m just a persistent messer around. At the moment my bike is complete so I’m looking for something to change. I have a Fuel can on at the moment which came with the bike and it’s ok but in my mind not a premium set up like the Leo Vince. Call me as much as you like it’s my hobby being stupid.

Me too. Love to tinker. Made a crap ton of bad decisions doing so but enjoyed the entire process! You do you as they say and glad that you found something to fiddle with. It's kind of funny. When something needs repairing, or I decide to undertake a project, it's never a bad day in my book.

 

[hulkss]

....there is no need legally for a cat so why not get rid of it.....

Fuel injection operates open loop during transients and heavy throttle conditions. The narrow band O2 sensors are too slow for transients and can not read rich heavy throttle fuel ratios. The EFI is then dependent on volumetric efficiency tables to compute the mix of air and fuel. If you change the exhaust, the VE tables will no longer be accurate and the fuel mixture will most likely be leaner than intended if flow through the exhaust system is increased.

 

[670cc]

Any restriction is too much. In the U.K. exhaust emissions are not tested so there is no need legally for a cat so why not get rid of it.
BTW I’ve just bought a Leo Vince full system off eBay for a good price.

I’m just thinking out loud here. What if the catalytic converter is actually less restrictive than the exhaust pipe that follows it? What if we substituted a piece of pipe for the cat and it added restriction? Without measurements and data, we would just be making assumptions.

 

[mzflorida]

I’m just thinking out loud here. What if the catalytic converter is actually less restrictive than the exhaust pipe that follows it? What if we substituted a piece of pipe for the cat and it added restriction? Without measurements and data, we would just be making assumptions.

Excellent point.

 

[Wedders]

Fuel injection operates open loop during transients and heavy throttle conditions. The narrow band O2 sensors are too slow for transients and can not read rich heavy throttle fuel ratios. The EFI is then dependent on volumetric efficiency tables to compute the mix of air and fuel. If you change the exhaust, the VE tables will no longer be accurate and the fuel mixture will most likely be leaner than intended if flow through the exhaust system is increased.

I have a Rapid Bike Easy fitted which hopefully will cope with that.
I have also bought a Leo Vince full de-cat system which will have been properly developed.

 

[wjvh]

I’m intrigued to know how this mod goes, both subjectively (how you feel it goes) and objectively (eg if you get any data like mpg, top speed, temperature, etc).
I prefer the look of the black widow system as it’s just a straight stainless pipe , but as you say the LV is a full designed system.

 

[Wedders]

I’m intrigued to know how this mod goes, both subjectively (how you feel it goes) and objectively (eg if you get any data like mpg, top speed, temperature, etc).
I prefer the look of the black widow system as it’s just a straight stainless pipe , but as you say the LV is a full designed system.

I won’t be able to supply data like mpg as I haven’t used the bike much, I bought it at the start of the first lockdown. I have also changed things like the front sprocket and added the Rapid Bike Easy since I bought it, so I am really starting from scratch. BTW I’ve also changed the colour.

 

[Moto Rider]

I won’t be able to supply data like mpg as I haven’t used the bike much, I bought it at the start of the first lockdown. I have also changed things like the front sprocket and added the Rapid Bike Easy since I bought it, so I am really starting from scratch. BTW I’ve also changed the colour.

I am like you. I changed the front sprocket the rear sprocket , a washable high flow air filter , a speedhealer and a wideband O2 emulator . LOL. Also i use the decated pipe of Leovince.

 

[bigbird]

In my experience LeoVince makes good quality kit.

 

[NCKidx]

Amazon works great, much lighter. $105.00

 

[TacomaJD]

View attachment 47659
Amazon works great, much lighter. $105.00

Pretty sure you just have an aftermarket slip on can, not a full de-cat head pipe that is being discussed here.

 

[Rapturee]

I’ll toss my hat in this ring. I recently bought a de-cat pipe form a member here and have yet to install it. As is my habit, I will do an A-B test recording my losses or gains whichever they are and post them. I know how my 12’ X acted and seems to respond very well with every mod I did to it for mpg increases. I’m very interested in seeing what the results will be with my 15’ DCT. With the snow and -F temps it’ll be a couple of months wait for me to be out on it. The rest of you fair weather riders, thank you for allowing the rest of us to ride vicariously through you!!

 

[NCKidx]

Pretty sure you just have an aftermarket slip on can, not a full de-cat head pipe that is being discussed here.

I can tell u there is no reason for that stock silencer to weigh as much as it does if there’s not a catalyst in it.

 

[670cc]

I can tell u there is no reason for that stock silencer to weigh as much as it does if there’s not a catalyst in itView attachment 47676

The NC's stock catalytic converter is mounted just after the cylinder head exhaust outlet, not inside the stock muffler. Remove the forward lower cowl and have a look.

The below image is of the traveling show cutaway model of the NC700X engine. Obviously your CC won't have a hole in the side of the casing.

 

[NCKidx]

Now that is a great cut away picture, thank you for getting my mind on the right track. I wonder what is inside that silencer. Do you happen to have a picture of that? I’ll be looking for a new header now lol.