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How to Fit CAT Eliminator Mid Pipe

34K views 81 replies 21 participants last post by  scott52 
#1 ·
This is quite an easy project to remove the catalytic convertor and replace with a mid pipe.

It may be illegal to do this on your road registered motorcycle. It would be prudent to check your local regulations :study: before you take to your exhaust with cutting disc!

I did this to my track bike.

 
#4 ·
Great video.

The small replacement pipe is from MJS Performance (http://www.mjsperformance.com/). They also offer the whole headers done this way.

I will most likely be doing the small pipe to complete my 'full system'; I don't care much about more power however 1) I got a Bazzaz TC/QS unit that I would want to be tuned with a cleaner exhaust path, and 2) the cat is burning my track fairings a little with the heat.

I'll be gutting my EGCV while I'm in there too.
 
#6 ·
Very cool thanks for the video. But headers seem like the better option imo
 
#13 ·
Anyone explain why the O2 sensor was refitted (bit of a PITA by the look of it) instead of just fitting an O2 sensor eliminator? It'd seem easier rather than drilling a hole through the nice new mid pipe and having to weld a sensor mount onto the side.
 
#14 ·
Well for outside the US the cost is a bit of a dealbreaker. $130 for a link pipe, $50 shipping plus taxes and VAT...Then, personally, I would have to pay someone to fit it, since I have 0 experience & equipment with welding etc... The cost definitely adds up.

I would say in my opinion, the arrow headers would seem like a better solution. Helpful video nevertheless. Thanks for sharing
 
#15 ·
You don't need to weld it, that's the point I was making in my previous post. It's a straight fit if you remove the O2 sensor and install the eliminator which is plug 'n' play.

From what I can tell, removing the cat will add the need for a PCV or similar or else the bikes A/F ratio will be off. When adding a PCV to bikes fitted with the O2 sensor you need to eliminate the O2 sensor or it will override the power commanders map settings and force the ecu to adjust the fuelling back to whatever the O2 sensor tells it it should be (making the new map useless).

I'm guessing that the bike in the video above has either removed the cat without installing a PCV or similar (not advisable), OR, he's removed the cat, installed a PCV as he should, then reconnected the O2 sensor which will render the new PCV map useless as the O2 sensor will override the PCV and its settings.
 
#22 ·
How much can the headers be had for in Europe? I reckon even with tax the mid pipe will work out a fair bit cheaper. Plus, the install will be a lot easier (I see a lot of people in threads saying they're struggling to fit them).

Also, Isn't there an issue with the arrow headers making oil filter changes difficult too? Larger diameter pipes mean coolant tank has to be removed or something I think?

As my bike is street only I am giving serious consideration to the mid pipe.
 
#24 ·
Thanks guys, I think I'm straight on the different scenarios. Maybe the OP was using autotune or similar...

Either way, I'm confident that if I were to plump for the mid pipe I'd just eliminate the O2 sensor and not need to drill or weld the thing (which I could easily do, it's my job lol. Just wanted to try and understand the thinking behind retaining the sensor).
 
#27 ·
On my arrow headers the o2 bung is on the right hand side of the exhaust (other side of GConns picture, in same location). I have the pcv and did the servo buddy to eliminate the servo motor. My bike did not have an o2 sensor. I have looked at the autotune but have deemed it unpractical for a street bike. Also set up looks confusing and time consuming if I were to install it myself (aside from my lack of knowledge with fuel management tech).
 
#29 ·
I'm sorry, you are correct - I forgot Scott was Aus, watching the video the first time I immediately just thought he was using the identical looking Dynojet Autotune module.

Looking back at your initial post, yeah, I would have just eliminated the sensor and not bothered poking a hole into this link pipe as well, he may have had his own reasons for keeping it perhaps.
 
#81 · (Edited)
Sorry for the extremely late response on this. I was out of action early in the year with injuries from a track crash. I recovered then came off the dirt bike and fractured my left distal radius. I got over that and went to Sepang Malaysia for two intensive days training on a ZX6R hired bike and got poleaxed by a fellow Aussie and ended up sliding down the road just past where Simoncelli was killed. I dam near needed a skin graft on my left elbow and had a really badly sprained right foot/ankle. I got the medico's to patch up the elbow and strap the ankle and I was back into it ... only missed one session. I did 15 x 20 minute sessions in two days in 32C and 85% humidity.

So for most of this year I've been distracted recovering from injury.

I run the full Bazzaz ZFiTC with the self mapping feature. Remember this is my race/track bike. The reason I welded the bung into the pipe was to take the Bazzaz wide band O2 sensor. I have my own AFR map that serves me well. The standard system runs a closed loop so an O2 sensor is already fitted at the entrance to the CAT. The standard sensor isn't wide band ... meaning it's not as accurate ... so it can't be used with the Bazzaz.

I have my table of AFR's for RPM and TP and the wide band O2 sensor collects the actual AFR's and then you apply the adjustment to the Honda map to get your target AFR's.

I would re-tune my bike about three times per day when at the track.

Sepang ... 5.5km and 15 corners. An awesome place.



Here I am in turn 2. This was the second day after being sent down the road on day one. The hire ZX6R's from SBR Track Days are very well maintained and set up. They're stock standard road bikes but go well.

 
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