That's the old 4 cylinder 250. Just so nobody thinks this one will sound like that. It never will.Also check this video out...
cbr250r exhaust before and after drilling - YouTube
His outlet pipe looks different than mine. It looks like he removed the outlet pipe that extends down halfway into the muffler and through a couple inner baffles and just left the back half of the can to open out the remaining hole?how do we get this sound??? any ideas people??
I think there will be performance gains from removing the cat material. Maybe not the full 1.5 horsepower that comes with a loud slip on because the stock baffling will still be much quieter/ restrictive, but it should improve due to less back pressure from the restriction of the cat.Back pressure won't be changed then?