I recently installed an Athena 290 kit on my 07 WR 250. Jetting is 40 pilot, OBEKR needle 5th groove from top, 172 main, 40 leak. Basically sea level to 100 ft, 50 degrees in NJ. Air box is opened up with a full GYTR exhaust system. Stock cams. ACV valve not bypassed, AIS is removed. Adjusted valves with new cam chain. The bike idles and accelerates great, with a couple short backfires on decel. Just between 1/8 and 1/4 throttle, it will cough slightly or hesitate, then run smooth all the way to full throttle. It gets better when hot. I can ride around it, but it would be nice to make it go away. I've tried a 42 and 38 pilot with no change, and tried an OBEKQ needle, which would only run in the bottom groove (full rich). Any ideas? OBEKP?? JD?