My buddy and I did the YZ timing conversion (finally got it right) on his WR250F and it really made quite a difference in my opinion. It is much more rev happy throughout the entire RPM range...SO I am going to do the conversion to my WR426F ASAP but this YZ NEEDLE thing is my real question. People have said this makes as much of a difference as changing the timing - any other opinions on that? If so, is the stock YZ needle the way to go? In the stock clip position? Is this an easy change? I've only replaced main/pilot jets before...the needle is in the top portion of the carb right? Any do's or don'ts to this or is it straight forward? Also I have the stock WR exhaust (baffle removed) right now but I am ordering a WB ProMeg ASAP....Will this mod along with the YZ timing change require a main/pilot jet change? Lot's of questions I know - I just want to get this right the first time because we are headed to the Hatfield/McCoy trails in WV for the LAbor Day weekend and I want to be able to roost my unsuspecting comrades who don't know I'm makeing these little mods - this is a covert operation...shhhhh!!