ive been noticing my 250 will misfire when revving, weird thing is it seems to pull through all the gears good, when I rev it with the clutch in it sounds like its got a limiter like a 4stroke 450. my jetting is 42 pilot,180 main with a pwk38.. shearer pipe, carls porting.. ive replaced the stator assembly and coil, this problem is hit or miss, sometimes it runs great does this sound like a cdi problem??

Most two strokes act rich at high RPM without a load on the engine.  It might be a little rich but you are close to having the correct main jet if it pulls through the lower gears without a high RPM miss-fire. 

If you install a main jet that runs clean at high RPM in neutral it will be too lean under a load.