Is there anyone here that has removed the exhaust flapper? I know there's not much gain in HP but i'm looking to get a louder sound out of it. I've got a 2012 CBR600RR. I'm also looking to see how involved it is.

 

well, its fully open when you are at wide open throttle and higher rpm. not much change going to come from removing it.

 

I had my flapper removed completely when I had my bike tuned. (They added block off plates, retune, flapper delete) Not much to be gained by just removing, I'd imagine.

 

ok, I'd like to change my answer please

Hahaha, sorry. I did a COMPLETE removal. The motor, the cables, all the stuff on the outside of the exhaust, and I even removed the valve and cut the shaft out, then plugged the holes.

Its not amazingly better, but its definitely a bit louder above 9k, and pulls harder up there too.

 

Then you're probably okay. You might be running a little rich down low though, since the ECU is expecting the recirculation system (Closed flap).

 

I'd suggest it will be leaner as its letting more air flow thru, for the same fuel maps.

Its pretty stinky tho, and no pops or other signs of lean.

Once I get the velocity stacks in, I plan on getting it dyno tuned.

 

Looks like you have your answer then. I didn't know much about velocity stacks on this bike, but I did find this while researching and wanted to share:

https://www.superstreetbike.com/hond...ack-mod#page-4

 

those are just modified/swapped around stock plastic pieces.

Venturi, TenKate and Factory Pro are all proven to make more power and allow the bike to make power right to redline.

Not huge numbers on stock bikes, but useful. And once you are not stock anymore, they keep on making more power.