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Author Topic: Remove 1200GS Catalytic Converter??  (Read 19253 times)

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Offline Far@way

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Re: Remove 1200GS Catalytic Converter??
« Reply #80 on: November 11, 2014, 12:55:11 pm »
i thought the lambda probe pre or post cat controls the fuelling on the scoot, wont decatting cause ireggular fuelling with possibility that motor will run too hot causing other kak
Hi, I have the same concern, if I do it myself? I spoke to Justin from Motorad Tech and he says you should dyno the bike after the cat was removed, so they can "tune" it better because apparently the BMW runs a bit "lean" to start with.
No worries...

Offline Geeser

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Re: Remove 1200GS Catalytic Converter??
« Reply #81 on: November 15, 2014, 11:28:26 pm »
So my 2 cents worth on this long debated topic...

Everything I read says don't remove the cat as fueling will need to be optimised aftewards. There are mixed reviews with regards additional noise/decibals and mixed opinions on performance gains - or not.

I have a 2009 1200 GSA and pondered over what route to follow. I fitted a "cut" sock silencer initially and it ran fine but quite a bit louder than stock.I could feel the bike ran lean and surged off idle and under constant light throttle low speed riding.

I then fitted a Bosson slip-on and my mid-range improved slightly, high rpm power from 6500 onward dropped off and I picked up an audible pinging at 5000rpm under certain throttle position. Noise levels were acceptable under constant cruise.

I was hesitant to decat as the fueling already seemed less than optimum. I fitted a thermocouple to fool the air temperature sensor and force enrichment but I experienced too much fuel enrichment and a drop in overall performance.

Finally I bit the bullet and bought a Power commander V, Autotuner and POD display. This setup let me create a target fuel map per cylinder, per gear. This took the performance and rideabilty to another level. Off idle low rpm pull away improved, mid range torque improved ... all round, the bike just ran significantly better.

So, back to decatting or not.. I eventually fitted my decatted header and the cut silencer, running on my current target air fuel ratio fuel map this week. I took the bike for it's test ride and once warmed up, pulled away hard in 2nd. The front wheel immediately picked up. It was not like this before. Mid range torque has definitely improved and the engine is a lot more responsive now.

I have since created a power biased fuel map for 1st, 2nd, 3rd and 4th gear and although it is still self teaching, the throttle response and midrange is fantastic.

The noise level has increased which doesn't bother me for in town riding. I have not yet done an open road ride so can't comment in this regard.

I think th e bottm line is that the bmsk cannot cope with major changes such as a decat. With an aftermarket fuel control module such as the PCV fitted, the bike most definitely bdnefits from exhast modifications including decatting.


Offline Copernicus

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Re: Remove 1200GS Catalytic Converter??
« Reply #82 on: December 03, 2014, 05:29:32 pm »
So on Tuesday I tackled my zorst myself, removed the bugger, and cut it open with a hacksaw at first then a grinder with a thin disk, then back to the Hacksaw when the disk started slipping  :o
I cut it on the wrong side as detailed in the pictures above so the cat removal was a little harder, but I just drilled and drilled into the offending blockage until it pretty much crumbled, I then used a grinding bit to clean out the left over bits.

Finally off to find a place to weld it up, Noise boys in Centurion doesnt do Stainless steel welding, carried on down the side street until I found a spot that does all kinds of welding, Turnweld Engineering. They charged me all of R200 to weld it up and they did a neat job, I will recommend them to anyone who needs welding done in Centurion, I will definitely use them again,  :thumleft:

The verdict, its a little louder, more of a growl, and hell it goes, the revs seem to climb a lot quicker than before. Very happy with this mod, and total cost was R200  :ricky:

I read through most of this thread and somewhere somebody said you lose about 15kg when you decat.  If I look at the pictures I cannot believe that the cat can weigh in at anything more than about 1kg.  I will not do it for the weight loss.

What is the life span of the cat?  If it becomes obsolete after x amount of years you can just as well remove it if it makes the bike go better.  Environmentally it then serves no purpose to keep it.

I don't think it will make much difference to fuel management either.  If there are no sensors at, or after, the cat, there can be no feedback to the system on whether it is there or not.
« Last Edit: January 27, 2015, 11:15:42 pm by Copernicus »
I started biking as an under achiever and it went downhill from there...

Offline Mikie

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Re: Remove 1200GS Catalytic Converter??
« Reply #83 on: December 04, 2014, 07:52:39 am »
definitely not 15kg , butif I rememeber correctly it is more than 1 Kg
Hardly noticeable either way with a weight reduction


Offline punisher

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Re: Remove 1200GS Catalytic Converter??
« Reply #84 on: December 04, 2014, 10:00:26 am »
Mine is being done by justine as we speak :D
just wanna have fun , and ride ... and ....... ride


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Re: Remove 1200GS Catalytic Converter??
« Reply #85 on: December 04, 2014, 01:24:14 pm »
Did mine myself last weekend.  Quite a messy job getting the cat out, but quick from there on.  Used the opportunity to polish the pipe, so to speak...  >:D