Decat… in situ? With headers still attached?

[AdamMathew]

I need advice here because I don’t know if I’m being too precious about my bike or whether this is as stupid an idea as I think it is. Please give me your opinion.

I have an aftermarket slip on but I’ve decided I want to get rid of the ugly cat box so I’m currently shopping for full pipe systems. My bike instructor friend (who is pretty mechanically sound minded) suggested I follow suit as he did with his old s1000xr and cut the cost by getting a Dominator brand cat eliminating mid pipe from Poland that’s around £130 which means instead of replacing the whole system, I only need to cut the cat out.

The kicker here is that he thinks he can cut the cat off the bike for me using a 9 inch cutting blade… whilst the exhaust system is still attached to the bike, as he did with his. Basically saving me the hassle of removing the headers. He says there’s enough room to do this without the blade hitting the bike.

I think this is a f***ing stupid idea and have no idea how he managed it the first time other than sheer luck.

Please for the love of sanity give me your opinion on the matter.

[CaptainSkinnyArms]

Just recently changing out my stock exhaust for a full Black Widow system I personally wouldn't try and cut the pipe still on the bike.  The area where you need to cut is very close to the oil pan.  I'd just drop the stock exhaust and do it the right way.  It's not that bad of a job just takes a little time and patience.  Youtube tutorials are your friend.

[Antares]

Originally Posted by Kugangles

Just recently changing out my stock exhaust for a full Black Widow system I personally wouldn't try and cut the pipe still on the bike.  The area where you need to cut is very close to the oil pan.  I'd just drop the stock exhaust and do it the right way.  It's not that bad of a job just takes a little time and patience.  Youtube tutorials are your friend.

This, spare those 2 hours and save yourself the headache. I personally don't really like the idea of that dominator pipe anyway but if you're gonna cut your exhaust at least you can measure properly when it's off the bike.
I have a spare OE exhaust in case it goes tits up 

[Crosshairs]

I installed my Dominator DeCat pipe without removing the header. I cut through the pipe from the bottom up with a hack saw and was just extra careful when I got close to the oil pan.
 
I personally dont like taking parts off unless necessary,and removing the header was a chore I just didn't want to deal with.

[mjojom]

Originally Posted by Crosshairs

I installed my Dominator DeCat pipe without removing the header. I cut through the pipe from the bottom up with a hack saw and was just extra careful when I got close to the oil pan.
 
I personally dont like taking parts off unless necessary,and removing the header was a chore I just didn't want to deal with.

I did exactly the same, cut through with an angle grinder until safe, and finished off with a hacksaw blade. Just to be sure I've inserted a thin bit of ply in between the oil pan and the exhaust. Then I used and hole saw on the cordless to rid of the catalysator.
however, I like a short slip-on, and with the decat pipe whole thing is too loud, with a proper slip-on, not so much.
I've gutted the silencer, welded stainless pieces of pipe on the silencer of the same diameter as on the dominator pipe that will go over the standard downpipe and now I can swap in between. when I feel I want her loud I install the de-cat pipe and when on long travels through Europe, ill stick the silencer back on.     

[PARMERE2410]

I have a 2021 S1000XR TE.
I am thinking of de cat the exhaust and reading all about it, I would prefer to cut the pipe rather than replace the headers.
Looking at the operation I feel that this is easily achievable with a little patience and buy a mid link pipe in stainless (about £160) to fit.
Has anyone the drawing or can advise where to mark the pipe for the cut please?
Peter

[1Jumper10]

If you remove the catylitic convertor do you have to re-flash? Also the O2 sensors. Are they left in place?

[CaptainSkinnyArms]

 O2 sensors are before the cat so you'll keep those.  In terms of flashing the bike after cat delete.  The ECU can compensate a bit from the increased exhaust flow but there are a lot of people who wouldn't recommend it.  I'd recommend a flash.  Bike runs way better with one.  At least mine does.