O.K guy's what's the best all around jetting specs you have come up with that works great year around in or near the north Georgia area? I currently running #48 pilot #172 main jet and N3CJ jet needle. My air screw ranges 1 1/2 to 2 1/2 turns depending. I still have some more work to do from closed throttle to 1/2 throttle range but the bike is running pretty clean at this time. One question I have is has anyone changed the power jet? Stock is #50. Can't find any info stating when this power jet comes into play. Manual says this circuit is active under 8,500 and 1/2 to full throttle. I know there is a solenoid valve on the carb that controls this circuit. I know it must be determind by throttle poistion due to the carb having a TPS and the pick up coil providing rpm to cdi unit. I guess I would need a tach installed and see at what rpm and throttle postion am at while riding. Is the power jet for hard acceleration only? Is the power jet even worth messing with? Any reason why the 2007 and newer YZ250's have 2 sizes richer on the jet needle? What changed in the engine/pipe to need the richer jet needle. Thanks.