Catalytic Converter

[2LZ]

Hi all,

As I'm getting to know the RX3 better and it's now fully broke in, like most other CB's, I feel there's more gusto inside dying to come out.

To date, the biggest obstacle against this release of possible new ponies has been the catalytic converter, causing a major damming effect on the free flow of escaping exhaust gasses. From all the searches I've done here, the cat, like Q's cat, thankfully lives in the muffler and not the head pipe.

I knocked Q's cat out long ago and had a noticeable increase in performance. Has anyone here knocked their cat out and if so, how? Is it accessible? I need to do this.

[madsocial]

Good morning 2LZ ,
While I do not have an answer to your question, my husband has asked me this a few times. It is probably the least discussed thing on the forum.

He's even asked about aftermarket options. I just stare back with this look

I look forward to see what some folks have to say about this. Thanks for bringing it up.

[2LZ]

Originally Posted by madsocial

Good morning 2LZ ,
While I do not have an answer to your question, my husband has asked me this a few times. It is probably the least discussed thing on the forum.

He's even asked about aftermarket options. I just stare back with this look

I look forward to see what some folks have to say about this. Thanks for bringing it up.

I share your husbands frustration. I don't have a single bike in my rolling stock with a stock muffler, with the exception of the RX3...and every bike and the Rhino have experienced improved performance due to it.

One would think....with as many of these things are out there running the globe (or something with a like exhaust), there would be some options or this would be talked about much more often. I'm not to worried about sound to much. The thing puts out a pretty good note when your "on it" already. It only makes sense though, that since these are originally designed without a cat for the rest of everyone else on the planet, and only really need one for the states....this addition of an exhaust blockage is obviously hampering its original design effort, just to pass EPA ad CARB.

I have a major bike project starting this afternoon (TT250 tear down) but as soon as it's done in a week or two, I want to dive into this cat issue. My feeling is that with the increased flow of exhaust gasses (post removal), the O2 sensor in the head pipe will more than be able to make up for the newly found lean condition of a quicker exiting exhaust. Theoretically, it should make for faster revs, minor increases across the entire power curve......if not just more "crisp".

Hell, worst case scenario is I wreck the dang muffler and need to order a new one from CSC, right?

[katoranger]

As long as the cat is behind the O2 sensor it should not affect the EFI.

[rtking]

The catalytic converter is at the base of the muffler can. The problem is that the exhaust pipe is welded to the can. I you can cut off the exhaust pipe, you can likely knock out the catalytic converter and reweld the pipe back on. Or if you have a really long, sharp metal pole, you could poke a hole through the honeycomb and allow gasses to flow freely.

Alternatively, the mufflers for the Honda CBR250R might work. There is some fabrication needed to extend the mid-pipe and to fabricate a mounting bracket (a piece of 1"x3"x.125" aluminum stock works well.) I have an Akrapovic muffler made for the CBR250R and it fits and sounds great.

In terms of power... I don't think that the stock exhaust is very restrictive, but I think the aftermarket exhaust does sound better. I put my bike (with Akrapovic mid-pipe and muffler) on the dyno and my air/fuel ratios was still running a touch rich.



Now... breathing just isn't exhaling, it's inhaling as well. I'm just playing with external stuff (easier on the wallet and my time) but anyone notice anything different here?

[2LZ]

You rock rtking! Thanks for the good info.
This has also been a frustration of mine over the years. I think the "King of All Things Pipe" is hoarding all of the stainless 1.25, 1.5, etc...exhaust pipe! I'd love to pick up an 8' length (or hell, a couple feet for that matter) and be able to bend my own!

[rtking]

Originally Posted by 2LZ

I think the "King of All Things Pipe" is hoarding all of the stainless 1.25, 1.5, etc...exhaust pipe! I'd love to pick up an 8' length (or hell, a couple feet for that matter) and be able to bend my own!

Thanks 2LZ. I just like to tinker. I haven't had time for a shake down ride, but I'm anxious to see what the results might be. Maybe next weekend.

In terms of finding 1.25 - 1.5" stainless pipe... a lot of OEM automobile manufacturers use 1.25 and 1.5" stainless exhaust tubing. So if you don't mind pre-used piping, it can be found cheaply at the wrecking yard. The muffler shop used 8" of used automotive 1.5" stainless steel piping to extend the stock Akropovic mid pipe. I used header wrap to cover the extended section since it comes close to the Evap Cannister and the rear brake's master cylinder.

[madsocial]

Originally Posted by rtking

I just like to tinker.

rtking , you are the man! You came with charts and pics!

[willy dog]

that air cleaner looks like it would be easy too get at unlike stock one

[2LZ]

Originally Posted by willy dog

that air cleaner looks like it would be easy too get at unlike stock one

No kidding! rtking, can you provide a link to the air cleaner? I'm a big "K&N-type" of filter guy.

Also, as I recall, you didn't get a "before" dyno reading? I hope your butt-dyno tells the story. Like I said prior, I've never NOT had a performance improvement with freeing up the breathing in any bike or car I've had, even if not just crisping up throttle response. I can't imagine that would be different here unless the injection is set at such fixed parameters that "it is what it is" and that's it.

[2LZ]

A dyno run of 22.5 is probably almost 25 or so at the crank, relatively guessing on gearing, etc...which should mean that rtking came in over factory spec.

[2LZ]

43mm....got it! Awesome, thanks.

Well......In the interest of public service (gasp, choke),...in all honesty, I just couldn't wait, I ended up ordering a new muffler for the RX3 yesterday afternoon. I'm not going to say what I got yet...and it's going to be a crap shoot regarding mounting.....but it measures out correctly for can length/pipe, etc....so once the TT is done, I'll be chasing this next. Rest assured it's not a pricey one like the Akropovic or a Yoshi or anything....but it was worth the gamble in my book for a beta test.

rtking, I'm just so impressed with the throttle response and how your bike has seemed to come to life in your videos....especially with that super tall gearing you have....I had to do something. It's all your fault man!!! ;-)

[SeerAtlas]

no offense to either of you guys, but in my lifelong experience, unless something is incredibly restrictive from the get-go, increasing your front end breathing only helps at the point something is restrictive at the first place, i.e. at or near full throttle/revs. Hard to imagine that the stock setup is choking the engine at lesser flow rate settings.....we'd have heard about the design engineer's execution......

[2LZ]

Originally Posted by SeerAtlas

no offense to either of you guys, but in my lifelong experience, unless something is incredibly restrictive from the get-go, increasing your front end breathing only helps at the point something is restrictive at the first place, i.e. at or near full throttle/revs. Hard to imagine that the stock setup is choking the engine at lesser flow rate settings.....we'd have heard about the design engineer's execution......

No offense taken, SeerAtlas! :-) We all know you're an ornery ol' cuss! ;-)

Simply put, I like pod filters. Zero chance of obstruction, even breathing and easy to service....and if you notice, I like to service my rolling stock. It's how I "play". No other real reasons. If they help with the breathing over the stock box, bonus!