Cylinder was on a healty runing bottom end but way not enough powerfull for me, good compression, has the thick sleeve in it no port job done at all. I have been told port are more restrictive than oem ones so that's why it wasn't developping much. I am not trying to teach someone something about the thick sleeve in it, maybe folks here could tell more about it than I have been tol about. I have been told this sleeve could be bore until to get 310, cylinder is currently on a 68.5mm bore with the actual piston that is going with. I was equal with newest 450 and my setup with that cylinder so not enough poneys, so I change it for a CT350 +4 mx ported cylinder, I will have to buy a new +4 crank and bearings also, having cases honed for it too.