01 YZ 426 with 07 450 carb- 165 Main 48 pilot 3rd clip needle Fuel screw 2 3/4 -3 turns out ..ish.. 2-4 thousand foot elevation I've been wrestling with this problem for awhile. I'm trying to get the best overall jetting performance out of this set up. I can no longer access the jetting sticky and I'm not sure if the stock 07 carb settings even apply here Half to full throttle is near perfect. There is a bit of hesitation from 1/8 to 1/4 throttle. The bike starts first kick hot or cold. Also, I think it's my lack of skill of setting the fuel screw correctly, but I also had an occasional irregular hot idle. Bike idles great without the choke while cold, but when fully warm it is sometimes irregular. It will start stumbling until it dies. I tried resetting the fuel screw today per the JD instructions I originally received with the fuel screw and ended up with 3 turns out approximately. Now from what I can tell I have alleviated the hot hiccup idle, but it is now very easy to kill the bike with a quick blip of the throttle on the stand when hot. I'd assume some amount of stumble without a load on the bike would be normal, but enough to actually kill the motor? Tips and pointers?