Hi I have installed a Hindle aftermarket pipe on my zx7, I went throught the process of rejetting. From what I understand in stock form bikes are set up lean and you normally have to richen up the mixture through main jets or shimming the needles ofter installing an afermarket pipe. When I installed the pipe it sounded as if it was very rich it would really pop out of the pipe on decceleration. I then leaned out the mixture and installed a Factory jet kit, it now pulls harder but still pops a bit on hard decceleration. Is it a buy product of free flowing pipes that they pop off throttle? Has anyone heard of this with hindle pipes on kawasaki's. Thanks for your input. I am new to this sight and must commend everyone invovlved it is a top notch sight.