Best $47.95 I ever spent. I recently installed this kit in my wife's 2015 CRF150F. From day 1, brand new, this bike never wanted to start and took FOREVER to warm up (revving it, having it die 500 times, turning up the idle just to turn it back down later....). It now doesn't even require the choke and idles almost instantly. I couldn't stop smiling! There is also a noticeable power increase, especially once she hits second. I read through all of the forums prior to install, here's what worked for me at Phoenix AZ conditions (elev 1170): 42 pilot, 115 main, power up needle clip installed 3 down from the blunt end. Removed the baffle from the stock exhaust, (left the spark arrestor in as we ride trails) removed the snorkel from the airbox. Again, this is what worked for me, others (forums) needed the fuel screw.
Just put this kit in my 2009 CRF 150F. Used 108/42 jets and new needle with clip on 4th setting. There was a small brass piece with new needle that I did not use on the 2009, not sure what is what is for. I did not adjust the fuel screw. Bike runs great now, with noticeable throttle response and more power. I also removed baffle, new air filter and opened up the air box. Thanks for a great product.