Attn all gear heads !

any advice is greatly appreciated!!
so I recently bought a 21 cbr1000rr-rSp. I have done a few mods and it’s not performing great. Ran beautifully before any changes were made. Here’s a list of the mods and issues I’m having.

-Akropovic stainless headers
-sprint filter
-SC Project crt slip on carbon
-Diec183 H5 exhaust servo eliminator from Motomillion (removed exhaust servo)
-brentune stage 1 ecu flash

bike sputters badly between 4700-5700 rpm in all gears w stock map and brentune map

RPM idles at 2000 and pulses with brentune flash installed.
idles normal with stock map

One major discrepancy I see is The stock and akropovic headers have different o2 sensor locations

-stock headers have one o2 sensor located on two left down pipes and one o2 sensor on two right down pipes.
​​​​​​-akropovic headers have one o2 sensor on the two outer pipes and one sensor on the two inner down pipes.
my next step is too re-install the stock headers to see if this eliminates the sputtering.
I’m scratching my head on this one for sure!!

top pic is stock bottom is akropovic

 

So the issue was the Akropovic exhaust. Due to the o2 sensors locations being different than stock it screwed up the tune. With or without the ecu flash. Reinstalled the stock headers and all issues fixed.
so now the mods are sprint filter, oem headers ,sc project crt exhaust , servo eliminator and brentune stage 1 ecu flash.
This bike is insane fast. Faster than the 21 s1000rr I sold to get this.