I just put on a new FMF Gold series pipe and I notice a lack of power in the bottom end. I seem to have gained in the top end is this normal and what should I do to get my bottom end back ? I moved my needle but that is it ?
The Fatty doesn't really take low-end power away from the KX250, it just seems to because of the enhanced midrange pull. But it shouldn't have mushy throttle response either if it's jetted correctly for the pipe. Pay close attention to the pilot circuit. You should be able to get very crisp response down low with the correct pilot jet and air screw setting. The needle also plays an important role. When you whack the throttle open, you are going directly to the needle.
keip82, the FMF shorty is a silencer not a pipe. The Fatty, Gnarly, Factory Fatty, and SST are pipes. The Shorty, Powercore 2, Titanium 2, TurbineCore 2, The "Q", PowerCore, and TurbineCore are silencers.